back to indexStephen Wolfram: Complexity and the Fabric of Reality | Lex Fridman Podcast #234
link |
The following is a conversation with Stephen Wolfram, his third time on the podcast.
link |
He's a computer scientist, mathematician, theoretical physicist, and the founder of
link |
Wolfram Research, a company behind Mathematica, Wolfram Alpha, Wolfram Language,
link |
and the new Wolfram Physics Project. This conversation is a wild, technical roller coaster
link |
ride through topics of complexity, mathematics, physics, computing, and consciousness. I think
link |
this is what this podcast is becoming, a wild ride. Some episodes are about physics, some about
link |
robots, some are about war and power, some are about the human condition and our search for meaning,
link |
and some are just what the comedian Tim Dillon calls fun. This is the Lex Friedman podcast.
link |
To support it, please check out the sponsors in the description. And now here's my conversation
link |
with Stephen Wolfram. Almost 20 years ago, you published a new kind of science,
link |
where you presented a study of complexity and an approach for modeling of complex systems.
link |
So let us return again to the core idea of complexity. What is complexity?
link |
I don't know. I think that's not the most interesting question. It's like,
link |
if you ask a biologist, what is life? That's not the question they care the most about.
link |
What I was interested in is how does something that we would usually identify as complexity
link |
arise in nature? And I got interested in that question 50 years ago, which is really embarrassingly
link |
a long time ago. How does snowflakes get to have complicated forms? How do galaxies get to have
link |
complicated shapes? How do living systems get produced? Things like that. And the question is,
link |
what's the underlying scientific basis for those kinds of things? And the thing that I was at first
link |
very surprised by, because I've been doing physics and particle physics and fancy mathematical
link |
physics and so on, and it's like, I know all this fancy stuff. I should be able to solve this basic
link |
science question. And I couldn't. This was like early maybe 1980ish time frame. And it's like, okay,
link |
what can one do to understand the sort of basic secret that nature seems to have? Because it
link |
seems like nature, you look around in the natural world, it's full of incredibly complicated forms.
link |
You look at sort of most engineered kinds of things. For instance, they tend to be, you know,
link |
we've got sort of circles and lines and things like this. And the question is, what secret does
link |
nature have that lets it make all this complexity that we in doing engineering, for example,
link |
don't naturally seem to have? And so that was the kind of the thing that I got interested in.
link |
And then the question was, could I understand that with things like mathematical physics? Well,
link |
it didn't work very well. So then I got to thinking about, okay, is there some other way to try to
link |
understand this? And then the question was, if you're going to look at some system in nature,
link |
how do you make a model for that system, for what that system does? So a model is some abstract
link |
representation of the system, some formal representation of the system. What is the
link |
raw material that you can make that model out of? And so what I realized was, well, actually,
link |
programs are really good source of raw material for making models of things. And, you know,
link |
in terms of my personal history, to me, that seemed really obvious. And the reason it seemed
link |
really obvious is because I just spent several years building this big piece of software that
link |
was sort of a predecessor to mathematical and morphine language, then called SMP, symbolic
link |
manipulation program, which was something that had this idea of starting from just these computational
link |
primitives and building up everything one had to build up. And so kind of the notion of, well,
link |
let's just try and make models by starting from computational primitives and seeing what we can
link |
build up. That seemed like a totally obvious thing to do. In retrospect, it might not have been
link |
externally quite so obvious, but it was obvious to me at the time, given the path that I happened
link |
to have been on. So, you know, so that got me into this question of, let's use programs to model
link |
what happens in nature. And the question then is, well, what kind of programs? And, you know,
link |
we're used to programs that you write for some particular purpose, and it's a big long piece
link |
of code, and it does some specific thing. But what I got interested in was, okay, if you just go out
link |
into the sort of computational universe of possible programs, you say, take the simplest
link |
program you can imagine, what does it do? And so I started studying these things called cellular
link |
automata. Actually, I didn't know at first they were called cellular automata, but I found that out
link |
subsequently. But it's just a line of cells, you know, each one is black or white. And it's just
link |
some rule that says the color of the cell is determined by the color that it had on the previous
link |
step. And it's two neighbors on the previous step. And I had initially thought that's, you know,
link |
sufficiently simple setup is not going to do anything interesting. It's always going to be
link |
simple, no complexity, simple rule, simple behavior. Okay, but then I actually ran the
link |
computer experiment, which is pretty easy to do. I mean, it probably took a few hours
link |
originally. And the results were not what I'd expected at all. Now, needless to say,
link |
in the way that science actually works, the results that I got a lot of unexpected things,
link |
which I thought were really interesting, but the really strongest result, which was already right
link |
there in the printouts I made, I didn't really understand for a couple more years. So it was,
link |
it was not, you know, the compressed version of the story is you run the experiment and you
link |
immediately see what's going on. But I wasn't smart enough to do that, so to speak. But the big,
link |
the big thing is, even with very simple rules of that type, sort of the minimal, tiniest program,
link |
sort of the, the one line program or something, it's possible to get very complicated behavior.
link |
My, my favorite example is the single rule 30, which is a particular cellular automaton rule,
link |
you just started off in one black cell, and it makes this really complicated pattern.
link |
And so that, for me, was sort of a critical discovery that then kind of said, playing back
link |
onto, you know, how does nature make complexity? I sort of realized that might be how it does it.
link |
That might be kind of the secret that it's using is that in this kind of computational
link |
universe of possible programs, it's actually pretty easy to get programs where even though
link |
the program is simple, the behavior when you run the program is not simple at all. And that was,
link |
so for me, that was the, the kind of the, the story of kind of how that, that was sort of the,
link |
the indication that one had got an idea of what the sort of secret that nature uses
link |
to make complexity and the complexity, how complexity can be made in other places.
link |
Now, if you say, what is complexity, you know, it's, it's complexity is, it's not easy to tell
link |
what's going on. That's the informal version of what is complexity.
link |
But there is something going on, but there's a rule to know what, right?
link |
Well, no, the rules can generate just randomness, right?
link |
Well, that's not obvious. In other words, that's not obvious at all.
link |
And it wasn't what I expected. It's not what people's intuition had been and has been for,
link |
you know, for a long time. That is one might think you have a rule, you can tell there's a
link |
rule behind it. I mean, it's just like, you know, the early, you know, robots in science fiction
link |
movies, right? You can tell it's a robot cause it does simple things, right? Turns out that isn't
link |
actually the right story. But it's not obvious that isn't the right story, because people assume
link |
simple rules, simple behavior. And that the sort of the key discovery about the computational
link |
universe is that isn't true. And that discovery goes very deep and relates to all kinds of things
link |
that I've spent years and years studying. But, you know, that in the end, the sort of the,
link |
the what is complexity is, well, you can't easily tell what it's going to do. You could just run the
link |
rule and see what happens. But you can't just say, Oh, you know, show me the rule. Great.
link |
And now I know what's going to happen. And, you know, the key phenomenon around that is this thing
link |
I call computational irreducibility, this fact that in something like rule 30, you might say,
link |
well, what's it going to do after a million steps? Well, you can run it for a million steps and just
link |
do what it does to find out. But you can't compress that you can't reduce that and say,
link |
I'm going to be able to jump ahead and say, this is what it's going to do after a million steps,
link |
but I don't have to go through anything like that computational effort.
link |
By the way, has anybody succeeded at that? You had a challenge, a competition.
link |
For predicting the middle column of rule 30.
link |
A number of people have sent things in and sort of people are picking away at it, but it's hard.
link |
I mean, it's, I've been, I've been actually even proving that the center column of rule 30
link |
doesn't repeat. That's something I think might be doable. Okay.
link |
Mathematically proving.
link |
Yes. And so that's analogous to a similar kind of things like the digits of Pi,
link |
which are also generated in this very deterministic way. And so a question is how random are the
link |
digits of Pi? For example, does every, first of all, does the digits of Pi ever repeat?
link |
Well, we know they don't because it was proved in the 1800s that Pi is not a rational number.
link |
So that means only rational numbers have digit sequences that repeat.
link |
So we know the digits of Pi don't repeat. So now the question is, does,
link |
you know, zero, one, two, three or whatever do all the digits base 10 or base two, or however
link |
you work it out, do they all occur with equal frequency? Nobody knows. That's far away from
link |
what can be understood mathematically at this point. And that's, that's kind of, but I'm even
link |
looking for step one, which is prove that the center column doesn't repeat, and then prove
link |
other things about it like equally distribution of equal numbers of zeros and ones. And those are
link |
things which I, you know, I kind of set up this little prize thing, because I thought those were
link |
not too out of range. Those are things which are within, you know, a modest amount of time,
link |
it's conceivable that those could be done. They're not, they're not far away from what
link |
current mathematics might allow. They'll require a bunch of cleverness and hopefully
link |
some interesting new ideas that, you know, will be useful other places.
link |
But you started in 1980 with this idea, before I think you realized, you know, this idea of
link |
programs, you thought that there might be some kind of thermodynamic like randomness, and then
link |
complexity comes from a clever filter that you kind of like, I don't know, spaghetti or something.
link |
You filter the randomness and outcomes complexity, which is an interesting intuition. I mean,
link |
how do we know that's not actually what's happening? So just because you were then able to develop,
link |
look, you don't need this like incredible randomness, you can just have very simple,
link |
predictable initial conditions and predictable rules. And then from that emerged complexity,
link |
still, there might be some systems where it's filtering randomness on the inputs.
link |
Well, the point is, when you have quotes randomness in the input, that means there's all kinds of
link |
information in the input. And in a sense, what you get out will be maybe just something close
link |
to what you put in. Like people are very in dynamical systems theory, sort of big area of
link |
mathematics that developed from the early 1900s and really got big in the 1980s. You know,
link |
an example of what people study there a lot. And it's popular version is chaos theory.
link |
An example of what people study a lot is the shift map, which is basically taking
link |
2x mod 1 to the fractional part of 2x, which is basically just taking digits in binary
link |
and shifting them to the left. So at every step, you get to see if you say, how big is this number
link |
that I got out? Well, the most important digit in that number is whatever ended up at the left
link |
hand end. But now if you start off from an arbitrary random number, which is quotes randomly
link |
chosen, so all its digits are random, then when you run that sort of chaos theory shift map,
link |
all that you get out is just whatever you put in, you just get to see what you what it's not
link |
obvious that you would excavate all of those digits. And if you're, for example, making a theory,
link |
I don't know, fluid mechanics, for example, if there was that phenomenon and fluid mechanics,
link |
then the equations of fluid mechanics can't be right. Because what that would be saying is
link |
the equations of that, that it matters to the fluid, what happens in the fluid at the level of
link |
the, you know, millionth digit of the initial conditions, which is far below the points at
link |
which you're hitting kind of sizes of molecules and things like that. So it's kind of almost
link |
explaining if that phenomenon is an important thing, it's kind of telling you that the fluid
link |
dynamics which describes fluids as continuous media and so on isn't really right. But so,
link |
you know, so this idea that, you know, there's a, it's a tricky thing, because as soon as you put
link |
randomness in, you have to know, you know, what, how much of what's coming out is what you put in
link |
versus how much is actually something that's being generated. And what's really nice about
link |
these systems where you just have very simple initial conditions, and where you get random stuff
link |
out or seemingly random stuff out, is you don't have that issue, you don't have to argue about
link |
was there something complicated put in, because plainly obvious there wasn't. Now,
link |
as a practical matter in doing experiments, the big thing is, if the thing you see is complex
link |
and reproducible, then it didn't come from just filtering some quotes randomness from the outside
link |
world. It has to be something that is intrinsically made, because it wouldn't otherwise be, I mean,
link |
you know, the, the, the, it could be the case that you set things up, and it's always the same each
link |
time. And you say, well, it's kind of the same, but it's not then it's not random each time,
link |
because kind of the definition of it being random is it was kind of picked, picked at random each
link |
time, so to speak. So is it possible to for sure know that our universe does not at the
link |
fundamental level have randomness? Is it possible to conclusively say there's no randomness at the
link |
bottom? Well, it's an interesting question. I mean, you know, science, natural science is an
link |
inductive business, right? You observe a bunch of things and you say, can we fit these together?
link |
What is our hypothesis for what's going on? The thing that I think I can say fairly definitively
link |
is at this point, we understand enough about fundamental physics that there is if there was
link |
sort of an extra dice being thrown, it's something that doesn't need to be there. We can get what
link |
we see without that. Now, you know, could you add that in as an extra little featureoid?
link |
You know, without breaking the universe? Probably. But in fact, almost certainly yes.
link |
But is it necessary for understanding the universe? No. And I think actually from a more
link |
fundamental point of view, it's, I think I might be able to argue. So one of the things that I've
link |
been interested in and been pretty surprised that I've had anything sentient to say about
link |
is the question of why does the universe exist? I didn't think that was a question that I would,
link |
you know, I thought that was a far out there metaphysical kind of thing. Even the philosophers
link |
have stayed away from that question for the most part. It's so such a kind of, you know, difficult
link |
to address question. But I actually think to my great surprise that from our physics project and
link |
so on, that it is possible to actually address that question and explain why the universe exists.
link |
And I kind of have a suspicion. I've not thought it through. I kind of have a suspicion that that
link |
explanation will eventually show you that in no meaningful sense, can there be randomness
link |
underneath the universe? That is that if there is, it's something that is necessarily irrelevant
link |
to our perception of the universe. That is that it could be there, but it doesn't matter. Because
link |
in a sense, we've already, you know, whatever it would do, whatever extra thing it would add,
link |
is not relevant to our perception of what's going on.
link |
So why does the universe exist? How does the irrelevance of randomness connect to
link |
the big why question of the universe? So, okay. So, I mean, why does the universe exist? Well,
link |
let's see. And is this the only universe we got? It's the only one. About that, I'm pretty sure.
link |
So you may be, which one, which of these topics is better to enter first? Why does the universe
link |
exist? And why you think it's the only one that exists?
link |
Well, I think they're very closely related. Okay. So, I mean, the first thing,
link |
let's see. I mean, this, why does the universe exist question is built on top of all these things
link |
that we've been figuring out about fundamental physics. Because if you want to know why the
link |
universe exists, you kind of have to know what the universe is made of. And I think the, well,
link |
let me, let me describe a little bit about the why does the universe exist question. So
link |
the main issue is, let's say you have a model for the universe. And you say, I've got this,
link |
this program or something, and you run it and you make the universe. Now you say, well, how do
link |
you act? Why is that program actually running? And people say, you've got this program that
link |
makes the universe, what computer is it running on? Right? What, what does it mean? What actualizes
link |
something, you know, two plus two equals four. But that's different from saying there's two,
link |
a pile of two rocks and another pile of two rocks and so many moves them together and makes four,
link |
so to speak. And so what is it that kind of turns it from being just this formal thing
link |
to being something that is actualized? Okay, so there we have to start thinking about, well,
link |
well, what do we actually know about what's going on in the universe? Well, we are
link |
observers of this universe. But confusingly enough, we're part of this universe. So in a sense,
link |
we, what, what, what, if we say, what do we, what do we know about what's going on in the
link |
universe? Well, what we know is what sort of our consciousness records about what's going on in
link |
the universe. And consciousness is part of the fabric of the universe. So we're in it.
link |
Yes, we're in it. And maybe I should, maybe I should start off by saying something about
link |
the consciousness story. Because that that's, maybe we should begin even before that at the
link |
very base layer of the Wolfram physics project. Maybe you can give a broad overview once again,
link |
really quick about this hypergraph model. Yes. And also, what is it a year and a half ago,
link |
since you've brought this project to the world, what is the status update? Where what are all the
link |
beautiful ideas you have come across? What are the interesting things you can mention?
link |
It's, I mean, it's a, it's a frigging Cambrian explosion. I mean, it's, it's crazy. I mean,
link |
there are all these things which I've kind of wondered about for years. And suddenly,
link |
there's actually a way to think about them. And I really did not see, I mean, the real strength
link |
of what's happened, I absolutely did not see coming. And the real strength of it is, we've
link |
got this model for physics, but it turns out it's a foundational kind of model that's a different
link |
kind of computation like model that I'm kind of calling the sort of multi computational model.
link |
And that, that kind of model is applicable not only to physics, but also to lots of other
link |
kinds of things. And one reason that's extremely powerful is because physics has been very successful.
link |
So we know a lot based on what we figured out in physics. And if we know that the same model
link |
governs physics and governs, I don't know, economics, linguistics, immunology, whatever,
link |
we know that the same kind of model governs those things. We can start using things that we've
link |
successfully discovered in physics and applying those intuitions in all these other areas. And
link |
that's, that's pretty exciting. And, and, and very surprising to me. And in fact, it's kind of like
link |
in the original story of sort of you go and you explain why is there complexity in the natural
link |
world, then you realize, well, there's all this complexity, there's all this computational
link |
irreducibility, you know, there's a lot we can't know about what's going to happen. It's kind of
link |
it's kind of a very confusing thing for people who say, you know, science has nailed everything
link |
down, we're going to, you know, based on science, we can know everything. Well, actually, there's
link |
this computational irreducibility thing, right in the middle of that, thrown up by science, so to
link |
speak. And then the question is, well, given computational irreducibility, how can we actually
link |
figure out anything about what happens in the world? Why aren't we, why are we able to predict
link |
anything? Why are we able to sort of operate in the world? And the answer is that we sort of live
link |
in these slices of computational reusability that exists in this kind of ocean of computational
link |
irreducibility. And it turns out that seems that it's a very fundamental feature of the kind of
link |
model that seems to operate in physics, and perhaps in the bottom of these other areas,
link |
that there are these particular slices of computational reusability that are relevant
link |
to us. And those are the things that both allow us to operate in the world, and not just have
link |
and not just have everything be completely unpredictable. But there are also things that
link |
potentially give us what amount to sort of physics like laws in all these other areas. So
link |
that's been sort of an exciting thing. But I would say that in general, for our project,
link |
it's been going spectacularly well. I mean, it's very, honestly, it wasn't something I expected
link |
to happen in my lifetime. I mean, it's something where it's, and in fact, one of the things about
link |
it, some of the things that we've discovered are things where I was pretty sure that wasn't how
link |
things worked. And turns out I'm wrong. And, you know, in a major area in mathematics, I'd be
link |
realizing that I've something I've long believed, we can talk about it later, that just really
link |
isn't right. But I think that the thing that, so what's happened with the physics project,
link |
I mean, you know, it's a can explain a little bit about how the how the model works. But basically,
link |
we can maybe ask you the following question. So it's easy through words describe how cellular
link |
automata works. You've explained this. And it's the fundamental mechanism by which you in your
link |
book, and you kind of science explored the idea of complexity and how to do science in this world
link |
of island reducible islands and irreducible generally irreducibility. Okay, so how does
link |
the model of hypergraphs differ from cellular automata? And how does the idea of multi computation
link |
differ? Like maybe that's a way to describe it. Right. We're, we're, you know, right. This is a,
link |
you know, my life is like all of our lives, something of a story of computational irreducibility.
link |
Yes. And, you know, it's been going for a few years now. So it's always a challenge to kind of
link |
find these appropriate pockets of reducibility. But let me see what I can do. So, so I mean,
link |
first of all, let's, let's talk about physics. First of all, and, you know, a key observation
link |
that one of the starting point of our physics project is things about what is space? What is
link |
the universe made of? And, you know, ever since Euclid, people just sort of say space is just this
link |
thing where you can put things at any position you want. And they're just points and they're just
link |
geometrical things that you can just arbitrarily put at different, different coordinate positions.
link |
So the first thing in our physics project is the idea that space is made of something,
link |
just like water is made of molecules, space is made of kind of atoms of space. And the only
link |
thing we can say about these atoms of space is they have some identity. There's a, there's a,
link |
there is, it's this atom as opposed to this atom. And, you know, you could give them, if you were a
link |
computer person, you give them UUIDs or something. But that's all there is to say about them,
link |
so to speak. And then all we know about these atoms of space is how they relate to each other.
link |
So we say these three atoms of space are associated with each other in some relation. So you can
link |
think about that as, you know, what atom of space is friends with what other atom of space?
link |
You can build this essentially friend network of the atoms of space. And the sort of starting
link |
point of our physics project is that's what our universe is. It's a giant friend network of the
link |
atoms of space. And so how can that possibly represent our universe? Well, it's like in
link |
something like water, you know, there are molecules bouncing around, but on a large scale,
link |
that, you know, that produces fluid flow and we have fluid vortices and we have all of these
link |
phenomena that are sort of the emergent phenomena from that underlying kind of collection of
link |
molecules bouncing around. And by the way, it's important that that collection of molecules
link |
bouncing around have this phenomenon of computational irreducibility. That's actually what
link |
leads to the second law of thermodynamics, among other things. And that leads to the sort of randomness
link |
of the underlying behavior, which is what gives you something which on a large scale seems like
link |
it's a smooth continuous type of thing. And so, okay, so first thing is space is made of something,
link |
it's made of all these atoms of space connected together in this network. And then everything
link |
that we experience is sort of features of the of that structure of space. So, you know, when we
link |
have an electron or something or a photon, it's some kind of tangle in the structure of space,
link |
much like kind of a vortex and a fluid would be just this thing that is, you know, it can actually
link |
the vortex can move around, it can involve different molecules in the fluid, but the vortex
link |
still stays there. And if you zoom out enough, the vortex looks like an atom itself, like a basic
link |
element. So there's the levels of abstraction. If you squint and kind of blur things out,
link |
it looks like at every level of abstraction, you can define what is a basic individual entity.
link |
Yes, but you know, in this model, there's a bottom level, you know, there's an elementary
link |
length, maybe 10 to the minus 100 meters, let's say, which is really small, you know,
link |
proton is 10 to the minus 15 meters, the smallest we've ever been able to sort of
link |
see with the particle accelerators around 10 to the minus 21 meters. So, you know, if we don't
link |
know precisely what the correct scale is, but it's perhaps over the order of 10 to the minus 100
link |
meters, so it's pretty small. And but that's the end, that's what things are made of.
link |
What's your intuition where the 10 to the minus 100 comes from? What's your intuition about this
link |
scale? Well, okay, so there's a calculation which I consider to be somewhat rickety, okay,
link |
which has to do with comparing. So, so there are various fundamental constants, there's the speed
link |
of light, the speed of light, once you know the elementary time, the speed of light is tells you
link |
the conversion from the elementary time to the elementary length. Then there's the question of
link |
how do you convert to the elementary energy? And how do you convert to between other things? And
link |
the various constants we know, we know the speed of light, we know the gravitational constant,
link |
we know Planck's constant and quantum mechanics, those are the three important ones.
link |
And we actually know some other things, we know things like the size of the universe,
link |
the Hubble constant, things like that. And essentially, this calculation of the elementary
link |
length comes from looking at these sort of combination of those, okay, so the most obvious
link |
thing, people have sort of assumed that quantum gravity happens at this thing, the Planck scale,
link |
10 to the minus 34 meters, which is the sort of the combination of Planck's constant and the
link |
gravitational constant and the speed of light that gives you that kind of length.
link |
Turns out in our model, there is an additional parameter, which is essentially the number of
link |
simultaneous threads of execution of the universe, which is essentially the number of sort of independent
link |
quantum processes that are going on. And that number, let's see if I remember that number,
link |
that number is 10 to the 170, I think, and so it's a big number. But that number then connects,
link |
you know, sort of modifies what you might think from all these Planck units to give you the
link |
things we're giving. And there's been sort of a mystery, actually, in the more technical physics
link |
thing, that the Planck mass, the Planck energy, Planck energy is actually surprisingly big.
link |
The Planck length is tiny, 10 to the minus 34 meters, that Planck time 10 to the minus
link |
43 meters, I think, seconds, I think. But the Planck energy is like the energy of a
link |
lightning strike, which is pretty weird. In our models, the actual elementary energy is that
link |
divided by the number of sort of simultaneous quantum threads, and it ends up being really small,
link |
too. And that sort of explains that mystery that's been around for a while about how Planck units
link |
work. But whether that precise estimate is right, we don't know yet. I mean, that's one of the things
link |
that's sort of been a thing we've been pretty interested in, is how do you see through, you
link |
know, how do you make a gravitational microscope that can kind of see through to the atoms of
link |
space? You know, how do you get in fluid flow, for example, if you go to hypersonic flow or
link |
something, you know, you've got a Mach 20, you know, space plane or something, it really matters
link |
that there are individual molecules hitting the space plane, not a continuous fluid. The question
link |
is, what is the analogous kind of, what is the analog of hypersonic flow for our, for things about
link |
the structure of spacetime? And it looks like a rapidly rotating black hole right at the sort of
link |
critical rotation rate is, it looks as if that's a case where essentially, the structure of spacetime
link |
is just about to fall apart. And you may be able to kind of see the evidence of sort of discrete
link |
elements, you know, you may be able to kind of see there, the sort of gravitational microscope
link |
of actually seeing these discrete elements of space. And there may be some effect in, for example,
link |
gravitational waves produced by rapidly rotating black hole, that in which one could actually see
link |
some phenomenon where one can say, yes, these don't come out the way one would expect,
link |
based on having a continuous structure of spacetime, that it is something where you can kind of see
link |
through to the discrete structure. We don't know that yet. So can you maybe elaborate a little
link |
bit deeper how a microscope that can see to 10 to the minus 100, how rotating black holes and
link |
presumably the detailed accurate detection of gravitational waves from black holes can
link |
reveal the discreetness of space? Okay, first thing is, what is a black hole? Actually, we need
link |
to go a little bit further in the story of what spacetime is, because I explained a little bit
link |
about what space is, but I didn't talk about what time is. And that's sort of important in
link |
understanding spacetime, so to speak. And your sense is both space and time in the story are
link |
discrete? Absolutely. Absolutely. But it's a complicated story and needless to say.
link |
Well, it's simple at the bottom. It's very simple at the bottom. It's very, in the end,
link |
it's simple but deeply abstract. And something that is simple in conception,
link |
but kind of wrapping one's head around what's going on is pretty hard.
link |
But so first of all, we have this, so I've described these kind of atoms of space and
link |
their connections. You can think about these things as a hypergraph. A graph is just,
link |
you connect nodes to nodes, but a hypergraph, you can have sort of not just friends,
link |
individual friends to friends, but you can have these triplets of friends or whatever else.
link |
And so we're just saying, and that's just the relations between atoms of space
link |
are the hyper edges of the hypergraph. And so we got some big collection of these atoms of
link |
space, maybe 10 to the 400 or something in our universe. And that's the structure of space.
link |
That's an every feature of what we experience in the world is a feature of that hypergraph,
link |
that spatial hypergraph. So then the question is, well, what does that spatial hypergraph do?
link |
Well, the idea is that there are rules that update that spatial hypergraph. And in a cellular
link |
automaton, you've just got this line of cells, and you just say at every step, at every time step,
link |
you've got fixed time steps, fixed array of cells. At every step, every cell gets updated
link |
according to a certain rule. And that's kind of the way it works. Now, in this hypergraph,
link |
it's sort of vaguely the same kind of thing. We say every time you see a little piece of
link |
hypergraph that looks like this, update it to one that looks like this. So it's just keep
link |
rewriting this hypergraph. Every time you see something that looks like that, anywhere in the
link |
universe, it gets rewritten. Now, one thing that's tricky about that, which we'll come to is this
link |
multi computational idea, which has to do with, you're not saying, in some kind of lock step way,
link |
do this one, then this one, then this one, it's just whenever you see one you can do,
link |
you can go ahead and do it. And that leads one not to have a single thread of time in the universe.
link |
Because if you knew which one to do, you would just say, okay, we do this one,
link |
then we do this one, then we do this one. But if you say just do whichever one you feel like,
link |
you end up with these multiple threads of time, these kind of multiple histories of the universe,
link |
depending on which order you happen to do the things you could do in.
link |
So it's fundamentally asynchronous and parallel?
link |
Yes. Yes. Which is very uncomfortable for the human brain that seeks for things to be sequential
link |
and synchronous. Right. Well, I think that this is part of the story of consciousness,
link |
is I think the key aspect of consciousness that is important for sort of parsing the universe
link |
is this point that we have a single thread of experience. We have a memory of what happened
link |
in the past, we can say something, predict something about the future, but there's a
link |
single thread of experience. And it's not obvious it should work that way. I mean, we've got 100
link |
billion neurons in our brains, and they're all firing in all kinds of different ways. But yet,
link |
our experience is that there is the single thread of time that goes along. And I think that,
link |
one of the things I've kind of realized with a lot more clarity in the last year,
link |
is the fact that we conclude that the universe has the laws it has is a consequence of the fact
link |
that we have consciousness the way we have consciousness. And so the fact, so I mean,
link |
just to go on with kind of the basic setup, it's, so we got this spatial hypergraph,
link |
it's got all these atoms of space, they're getting these little clumps of atoms of space
link |
are getting turned into other clumps of atoms of space, and that's happening everywhere in the
link |
universe all the time. And so one thing that's a little bit weird is there's nothing permanent
link |
in the universe. The universe is getting rewritten everywhere all the time. And if it wasn't getting
link |
rewritten, space wouldn't be knitted together. That is, space would just fall apart. There wouldn't
link |
be any way in which we could say this part of space is next to this part of space. One of the
link |
things that people were confused about back in antiquity, the ancient Greek philosophers and
link |
so on is how does motion work? How can it be the case that you can take a thing that we can walk
link |
around? And it's still us when we walked a foot forward, so to speak. And in a sense with our
link |
models, that's again, a question, because it's a different set of atoms of space when we, you know,
link |
when I move my hand, it's moving into a different set of atoms of space. It's having to be recreated,
link |
it's not the thing itself is not there, it's being continuously recreated all the time. Now,
link |
it's a little bit like waves in an ocean, you know, vortices and fluid, which again, the actual
link |
molecules that exist in those are not what define the identity of the thing. And but it's a little
link |
bit, you know, this idea that there can be pure motion, that it can, that it is even possible
link |
for an object to just move around in the universe and not change. It's not self evident that such
link |
a thing should be possible. And that is part of our perception of the universe is that we
link |
parse those aspects of the universe where things like pure motion are possible. Now, pure motion,
link |
even in general relativity, the theory of gravity, pure motion is a little bit of a complicated thing.
link |
I mean, if you imagine your average, you know, teacup or something approaching a black hole,
link |
it is deformed and distorted by the structure of space time. And to say, you know, is it really
link |
pure motion? Is it that same teacup that's the same shape? Well, it's a bit of a complicated story.
link |
And this is a more extreme version of that. So, so anyway, the thing that that's happening is
link |
we got space, we've got this notion of time. So time is this kind of this rewriting of the
link |
hypergraph. And one of the things that's important about that time is this sort of computational
link |
irreducible process. There's something, you know, time is not something where it's kind of the
link |
mathematical view of time tends to be time is just a coordinate, we can, you know, slide a slider,
link |
turn a knob, and we'll change the time that we've got in this equation. But in this picture of time,
link |
that's not how it works at all. Time is this inexorable, irreducible kind of set of computations
link |
that go on that go from where we are now to the future. But so so the thing, and one of the things
link |
that is again, something one sort of has to break out of is your average trained physicist like me
link |
says, you know, space and time are the same kind of thing. They're related by, you know, the prank
link |
array group and Lawrence transformations and relativity and all these kinds of things. And,
link |
you know, space and time, you know, there are all these kind of sort of folk stories you can tell
link |
about why space and time are the same kind of thing. In this model, they're fundamentally not
link |
the same kind of thing. Space is this kind of sort of connections between these atoms of space.
link |
Time is this computational process. So the thing that the first sort of surprising thing
link |
is, well, it turns out you get relativity anyway. And the reason that happens that a few bits and
link |
pieces here, which one has to understand, but but the fundamental point is, if you are an observer
link |
embedded in the system, that a part of this whole story of things getting updated in this way and
link |
that, there are there's sort of a limit to what you can tell about what's going on. And really,
link |
in the end, the only thing you can tell is what are the causal relationships between events. So an
link |
event in this sort of an elementary event is a little piece of hypergraph got rewritten. And
link |
that means a few hyper edges of the hypergraph were consumed by the event. And you produce some
link |
other hyper edges. And that's an elementary event. And so then the question is, what we can tell
link |
is kind of what the network of causal relationships between elementary events is.
link |
That's the ultimate thing, the causal graph of the universe. And it turns out that, well, there's
link |
this property of causal invariance that is true of a bunch of these models. And I think is inevitably
link |
true for a variety of reasons. That makes it be the case that it doesn't matter kind of if you are
link |
sort of saying, well, I've got this hypergraph, and I can rewrite this piece here and this piece
link |
here. And I do them all in different orders. When you construct the causal graph for each of those
link |
orders, that you choose to do things in, you'll end up with the same causal graph. And so that's
link |
essentially why, well, that's in the end, why relativity works. It's why our perception of
link |
space and time is as having this kind of connection that relativity says they should have. And that's
link |
kind of how that works. I think I'm missing a little piece. If we can go there again, you said
link |
the fact that the observer is embedded in this hypergraph, what's missing? What is the observer
link |
not able to state about this universe of space and time? If you look from the outside, you can say,
link |
oh, I see this particular place was updated, and then this one was updated, and I'm seeing
link |
which order things were updated in. But the observer embedded in the universe doesn't know
link |
which order things were updated in, because until they've been updated, they have no idea what else
link |
happened. So the only thing they know is the set of causal relationships. Let me give an extreme
link |
example. Let's imagine that the universe is a Turing machine. Turing machines have just this one
link |
update head, which does something, and otherwise the Turing machine just does nothing. And the
link |
Turing machine works by having this head move around and do its updating just where the head
link |
happens to be. The question is, could the universe be a Turing machine? Could the universe just have
link |
a single updating head that's just zipping around all over the place? You say, that's crazy, because
link |
I'm talking to you, you seem to be updating, I'm updating, etc. But the thing is, there's no way
link |
to know that, because if there was just this head moving around, it's like, okay, it updates me,
link |
but you're completely frozen at that point. Until the head has come over and updated you,
link |
you have no idea what happened to me. And so if you unravel that argument, you realize the only
link |
thing we actually can tell is what the network of causal relationships between the things that
link |
happened were. We don't get to know from some sort of outside sort of God's eye view of the thing.
link |
We don't get to know what sort of from the outside what happened. We only get to know
link |
sort of what the set of relationships between the things that happened actually were.
link |
Yeah, but if I somehow record like a trace of this, I guess we'll be called multi computation.
link |
Can't I then look back? When you record the trace some you place throughout the universe,
link |
like throughout, like a log that records in my own pocket of in this hypergraph, can't I
link |
like realizing that I'm getting an outdated picture? Can't I record?
link |
See, the problem is, and this is where things start getting very entangled in terms of what
link |
one understands. The problem is that any such recording device is itself part of the universe.
link |
So you don't get to say, you never get to say, let's go outside the universe and go do this.
link |
And that's why, I mean, lots of the features of this model and the way things work end up
link |
being a result of that. So, but what I guess from on a human level, what is
link |
the cost you're paying? What are you missing from not getting an updated picture all the time?
link |
Okay, I got, I understand what you're just saying. Yeah, yeah, right.
link |
But like what, like how does consciousness emerge from that? Like how, like, what are the
link |
limitations of that observer? I understand you're getting a delay. Well, there's a, okay,
link |
there's, there's, there's a bunch of limitations of the observer, I think. Maybe just explain
link |
something about quantum mechanics, because that maybe is a, is an extreme version of some of
link |
these issues, which helps to kind of motivate why one should sort of think things through a little
link |
bit more carefully. So one feature of the, of this, okay, so in standard physics, like high
link |
school physics, you learn, you know, the equations of motion for a ball. And the, the, you know,
link |
it says, you throw the ball this angle, this velocity, things will move in this way. And
link |
there's a definite answer, right? The story, the key story of quantum mechanics is there
link |
aren't definite answers to where does the ball go? There's kind of this whole sort of bundle of
link |
possible paths. And all we say we know from quantum mechanics is certain probabilities
link |
for where the ball will end up. Okay. So that's kind of the, the core idea of quantum mechanics.
link |
So in our models, you, quantum mechanics is not some kind of plug in add on type thing.
link |
You absolutely cannot get away from quantum mechanics, because as you think about updating
link |
this hypergraph, there isn't just one sequence of things, one definite sequence of things that
link |
can happen. There are all these different possible update sequences that can occur. You could do
link |
this, you know, piece of the hypergraph now, and then this one later, and et cetera, et cetera,
link |
et cetera. All those different paths of history correspond to these quantum, quantum paths and
link |
quantum mechanics, these different possible quantum histories. And one of the things that's
link |
kind of surprising about it is they, they branch, you know, there can be a certain state of the
link |
universe, and it could do this or it could do that, but they can also merge. There can be two
link |
states of the universe, which their next state, the next state they produce is the same for both
link |
of them. And that process of branching and merging is kind of critical. And the idea that they can
link |
be merging is critical and somewhat nontrivial for these hypergraphs, because there's a whole
link |
graph isomorphism story, and there's a whole very elaborate set of mathematics.
link |
That's where the causal invariance comes in.
link |
Yes, among other things. Right. Yes. But so then what happens is that what one's seeing,
link |
okay, so we've got this thing, it's branching, it's merging, et cetera, et cetera, et cetera.
link |
Okay, so now the question is, how do we perceive that? What, you know, how do we,
link |
do we, why don't we notice that the universe is branching and merging? Why, you know, why is it
link |
the case that we just think a definite set of things happen? Well, the answer is we are embedded
link |
in that universe, and our brains are branching and merging too. And so what quantum mechanics
link |
becomes a story of is how does a branching brain perceive a branching universe? And the key thing
link |
is, as soon as you say, I think definite things happen in the universe, that means you are essentially
link |
conflating lots of different parts of history. You're saying, actually, as far as I'm concerned,
link |
because I'm convinced that definite things happen in the universe, all these parts of history must
link |
be equivalent. Now, it's not obvious that that would be a consistent thing to do. It might be,
link |
you say, all these parts of history are equivalent, but by golly, moments later, that would be a
link |
completely inconsistent point of view. Everything would have, you know, gone to hell in different
link |
ways. The fact that that doesn't happen is, well, that's a consequence of this causal
link |
invariance thing. But that's, and the fact that that does happen a little bit is what causes little
link |
quantum effects. And that if that didn't happen at all, there wouldn't be anything that sort of
link |
is like quantum mechanics. It would be quantum mechanics is kind of like in this,
link |
in this kind of this bundle of paths. It's a little bit like what happens in statistical
link |
mechanics and fluid mechanics, whatever, that most of the time, you just see this continuous fluid,
link |
you just see the world just progressing in this kind of way that's like this continuous fluid.
link |
But every so often, if you look at the exact right experiment, you can start seeing, well,
link |
actually, it's made of these molecules where they might go that way, or they might go this way.
link |
And that's kind of quantum effects. And so that's so the this kind of idea of where we're sort of
link |
embedded in the universe, this branching brain is perceiving this branching universe. And that ends
link |
up being sort of a story of quantum mechanics. That's, that's part of the whole picture of
link |
what's going on. But I think, I mean, to come back to sort of where does conscious, what is,
link |
what is the story of consciousness? So in the universe, we've got, you know, whatever it is,
link |
10 to the 400 atoms of space, they're all doing these complicated things. It's all a big, complicated,
link |
irreducible computation. The question is, what do we perceive from all of that? And the answer is that
link |
we are, we are parsing the universe in a particular way. Let me again, go back to the gas molecules
link |
analogy. You know, in the gas in this room, there are molecules bouncing around all kinds of complicated
link |
patterns. But we don't care. All we notice is there's, you know, the gas laws are satisfied.
link |
Maybe there's some fluid dynamics. These are kind of features of that assembly of molecules that we
link |
notice. And then lots of details we don't notice. When you say we, do you mean the tools of physics,
link |
or do you mean literally the human brain and its perception system?
link |
Well, okay. So the human brain is where it starts, but we built a bunch of instruments to do a bit
link |
better than the human brain. But they still have many of the same kinds of ideas, you know, their
link |
cameras and their pressure sensors and these kinds of things. They're not, you know, at this point,
link |
we don't know how to make fundamentally qualitatively different sensory devices.
link |
Right. So it's always just an extension of the conscious experience or our sensory experience.
link |
Sensory experience, but sensory experience that's somehow intricately tied to consciousness.
link |
Right. Well, so, so one question is when we are looking at all these molecules in the gas,
link |
and there might be 10 to 20 molecules in some little, little box or something, it's like,
link |
what, what do we notice about those molecules? So one thing that we can say is we don't notice
link |
that much. We are, you know, we are computationally bounded observers. We can't go in and say,
link |
okay, I'm the 10 to 20th molecules, and I know that I can sort of decrypt their motions and I
link |
can figure out this and that. It's like, I'm just going to say what's the average density of molecules.
link |
And so one key feature of us is that we are computationally bounded. And that when you
link |
are looking at a universe, which is full of computation and doing huge amounts of computation,
link |
but we are computationally bounded, there's only certain things about that universe that
link |
we're going to be sensitive to. We're not going to be, you know, figuring out what all the atoms
link |
of space are doing, because we're just computationally bounded observers, and we are only sampling
link |
these, these small set of features. So I think the two defining features of consciousness that,
link |
and I, you know, I would say that the sort of the preamble to this is for years, you know,
link |
because I've talked about sort of computation and fundamental features of physics and science,
link |
people ask me, so what about consciousness? And I, for years, I've said, I have nothing to say
link |
about consciousness. And, you know, I've kind of told this story, you know, you talk about
link |
intelligence, you talk about life. These are both features where you say, what's the abstract
link |
definition of life, we don't really know the abstract definition, we know the one for life on
link |
earth, it's got RNA, it's got cell membranes, it's got all this kind of stuff. Similarly,
link |
for intelligence, we know the human definition of intelligence, but what is intelligence abstractly,
link |
we don't really know. And so what I've long believed is that sort of the abstract definition
link |
of intelligence is just computational sophistication. That is, that as soon as you can be computationally
link |
sophisticated, that's kind of the abstract version, the generalized version of intelligence.
link |
So then the question is, what about consciousness? And what I sort of realized is that consciousness
link |
is actually a step down from intelligence. That is, that you might think, oh, you know,
link |
consciousness is the top of the pile. But actually, I don't think it is. I think that there's this
link |
notion of kind of computational sophistication, which is the generalized intelligence. But
link |
consciousness has two limitations, I think. One of them is computational boundedness. That is,
link |
that we're only perceiving a sort of computationally bounded view of the universe. And the other is
link |
this idea of a single thread of time. That is, that we, and in fact, we know neurophysiologically,
link |
our brains go to some trouble to give us this one thread of attention, so to speak. And it
link |
isn't the case that, you know, in all the neurons in our brains, that, that in at least in our conscious,
link |
note the, you know, the correspondence of language in our conscious experience,
link |
we just have the single thread of attention, single thread of, of perception. And, you know,
link |
maybe there's something unconscious that's bubbling around. That's the kind of almost the quantum
link |
version of what's happening in our brain, so to speak. We've got the, the classical flow of what
link |
we are mostly thinking about, so to speak. But there's this kind of bubbling around of other
link |
paths that is all those other neurons that didn't make it to be part of our sort of conscious stream
link |
of experience. So in that sense, intelligence as computational sophistication is much broader
link |
than, than the, the computational constraints, which consciousness operates under and also
link |
the sequential, like the sequential thing, like the notion of time. That's, that's kind of interesting.
link |
But then the, the follow up question is like, okay, starting to get a sense of what is intelligence
link |
and how does that connect to our human brain? Because you're saying
link |
intelligence is almost like a fabric, like what we like plug into it or something. Like,
link |
yeah, I think, you know, people, our consciousness plugs into it.
link |
Yeah. I mean, the intelligence, I think the core, I mean, you know, intelligence at some
link |
level is just a word, but we're asking, you know, what is the, the notion of intelligence
link |
as we generalize it beyond the bounds of humans, beyond the bounds of even the AIs that we humans
link |
have built and so on, you know, what, what is intelligence? You know, is the weather, you know,
link |
people say the weather has a mind of its own. What does that mean? You know, can the weather be
link |
intelligent? Yeah. What does agency have to do with intelligence here? So is intelligence just
link |
like your conception of computation? Just intelligence is a, is the capacity to perform
link |
computation in the sea of? Yeah, I think so. I mean, I think that's right. And I think that,
link |
you know, this question of, of, is it for a purpose? Okay. That quickly degenerates into
link |
a horrible philosophical mess. Because, you know, whenever you say, did the weather do that for a
link |
purpose? Yeah. Right? Well, yes, it did. It was trying to move a bunch of hot air from the equator
link |
to the poles or something. That's its purpose. But why? Because I seem to be equally as dumb
link |
today as I was yesterday. So there's some persistence, like a consistency over time
link |
that the intelligence I plugged into. So like, what's, it seems like there's a hard constraint.
link |
Well, that's not. Between the amount of computation I can perform in my consciousness.
link |
Like they seem to be really closely connected somehow. Well, I think the point is that the
link |
thing that gives you kind of the ability to have kind of conscious intelligence,
link |
you can have kind of this. Okay. So, so one thing is we don't know intelligence is other
link |
than the ones that are very much like us. Yes. Right. And the ones that are very much like us,
link |
I think have this feature of single thread of time bounded, you know, computationally bounded.
link |
Now, that, but you also need computational sophistication. Having a single thread of
link |
time and being computationally bounded, you could just be a clock going tick tock, you know,
link |
that would satisfy those conditions. But the fact that we have this sort of irreducible,
link |
you know, computational ability, that's, that's an important feature. That's, that's the sort of
link |
the bedrock on which we can construct the things we construct. Now, the fact that we have this
link |
experience of the world that has the single thread of time and computational boundedness,
link |
the thing that I sort of realized is it's that that causes us to deduce from this irreducible
link |
mess of what's going on in the physical world, the laws of physics that we think exist. So,
link |
in other words, if we say, why do we believe that there is, you know, a continuous space,
link |
let's say, why do we believe that gravity works the way it does? Well, in principle,
link |
we could be kind of parsing details of the universe that were, you know, that, okay,
link |
the analogy is, again, with the statistical mechanics and molecules in a box, we could be
link |
sensitive to every little detail of the swirling around of those molecules. And we could say,
link |
what really matters is the, you know, the wiggle effect. Yes. That is, you know, that is something
link |
that we humans just never notice because it's some weird thing that happens when there are 15
link |
collisions of air molecules and this happens and that happens. We just see the pure motion of a
link |
ball moving about. Right. Why do we see that? Right. And the point is that, that what seems
link |
to be the case is that the things that if we say, given this sort of hypergraph that's updating and
link |
all the details about all the sort of, sort of atoms of space and what they do, and we say,
link |
how do we slice that to what we can be sensitive to? What seems to be the case is that as soon as
link |
we assume, you know, computational boundedness, single thread of time, that leads us to general
link |
relativity. In other words, we can't avoid that. That that's the way that we, we will parse the
link |
universe. Given those constraints, we parse the universe according to those particular,
link |
in such a way that we say the aggregate reducible, sort of, pocket of computational
link |
reducibility that we slice out of this kind of whole computationally irreducible ocean of behavior
link |
is just this one that corresponds to general relativity. Yeah, but we don't perceive general
link |
relativity. Well, we do if we do fancy experiments. So you're saying, so perceive really does mean
link |
the fault. We drop something. That's a great example of general relativity in action. No,
link |
but like, what's the difference between that and Newtonian mechanics? I mean,
link |
Oh, it doesn't. This is, when I say general relativity, that's even gravity, the Uber theory,
link |
so to speak. I mean, Newtonian gravity is just the approximation that we can make,
link |
you know, on the earth and things like that. So, so this is, you know, the phenomenon of gravity
link |
is one that is a consequence of, you know, we would perceive something very different from
link |
gravity. So, so the way to understand that is when we think about, okay, so we make up reference
link |
frames with which we parse what's happening in space and time. So in other words, one of the,
link |
one of the things that we do is we say, as time progresses, everywhere in space is something
link |
happens at a particular time. And then we go to the next time, and we say, this is what space is
link |
like at the next time, this is what space is like at the next time. That's, it's the reason we are
link |
used to doing that is because, you know, when we look around, we might see, you know, 10, 100 meters
link |
away. The time it takes light to travel that distance is really short compared to the time it
link |
takes our brains to know what happened. So as far as our brains are concerned, we are parsing the
link |
universe in this, there is a moment in time, it's all of space, there's a moment in time, it's all
link |
of space. You know, if we were the size of planets or something, we would have a different perception
link |
because the speed of light would be much more important to us. We wouldn't have this perception
link |
that things happen progressively in time, everywhere in space. And so that's an important
link |
kind of constraint. And the reason that we kind of parse the universe in the way that causes us to
link |
say gravity works the way it does, is because we're doing things like deciding that we can say the
link |
universe exists, space has a definite structure. There is a moment in time, space has this definite
link |
structure, we move to the next moment in time, space has another structure. That kind of setup
link |
is what lets us kind of deduce kind of what to parse the universe in such a way that we say
link |
gravity works the way it does. So that kind of reference frame is that the illusion of that
link |
is that you're saying that somehow useful for consciousness. That's what consciousness does,
link |
because in a sense, what consciousness is doing is it's insisting that the universe is kind of
link |
sequentialized. That is, and it is not allowing the possibility that, oh, there are these multiple
link |
threads of time, and they're all flowing differently. It's like saying, no, everything is happening in
link |
this one thread of experience that we have. And that illusion of that one thread of experience
link |
cannot happen at the planetary scale. Are you saying typical human? Are you saying we are at a
link |
human level special here for consciousness? Well, for our kind of consciousness, if we existed at
link |
a scale close to the elementary length, for example, then our perception of the universe
link |
will be absurdly different. But this makes consciousness seem like a weird side effect
link |
to this particular scale. And so who cares? I mean, the consciousness is not that special.
link |
I think that a very interesting question is, which I've certainly thought a little bit about,
link |
is what can you imagine? What is a sort of factoring of something? What are some other
link |
possible ways you could exist, so to speak? And if you were a photon, if you were some kind of
link |
thing that was kind of intelligence represented in terms of photons. For example, the photons we
link |
receive in the cosmic microwave background, those photons, as far as their concern, the universe
link |
just started. They were emitted 100,000 years after the beginning of the universe. They've
link |
been traveling at the speed of light. Time stayed still for them. And then they just arrived and we
link |
just detected them. So for them, the universe just started. And that's a different perception of
link |
that has implications for a very different perception of time. They don't have that
link |
single thread that seems to be really important for being able to tell a heck of a good story.
link |
So we humans tell a story. We can tell a story. Right. We can tell a story. What other kinds of
link |
stories can you tell? So a photon is a really boring story. Yeah. I mean, so that's a, I don't
link |
know if they're a boring story, but I think it's, I've been wondering about this and I've been
link |
asking friends of mine who have science fiction writers and things, have you written stuff about
link |
this? And I've got one example, great, great collection of books from my friend Rudy Rucker,
link |
which were, which I have to say, the, their books about, that are very informed by a bunch of science
link |
that I've done. And the thing that I really loved about them is, you know, in the first
link |
chapter of the book, the earth is consumed by these things called nants, which are nano,
link |
nanobot type things. Nice. So, you know, so the earth is gone in the first, but then it comes back.
link |
But, but, but then spoiler alert. Yeah, right. That was a, that was only a micro spoiler. It's
link |
only chapter one. Okay. It's, it's the, but, but the thing that is, is not a real spoiler alert
link |
because it's such a complicated concept. But, but in the end, in the end, the, the earth is saved
link |
by this thing called the principle of computational equivalence, which is a kind of a core scientific
link |
idea of mine. And I was just like, like thrilled. I don't read fiction books very often. And I was
link |
just thrilled. I get to the end of this. And it's like, Oh my gosh, you know, everything is saved
link |
by this sort of deep scientific principle. Can you, can you maybe elaborate how the principle
link |
of computational equivalence can save a planet? That would, that would be a terrible spoiler for
link |
me. That would be a spoiler. Okay. But, but, but no, but let me say what the principle of
link |
computational equivalence is. So the question is, you are, you have a system, you have some rule,
link |
you can think of its behavior as corresponding to a computation. The question is, how sophisticated
link |
is that computation? The statement of the principle of computational equivalence is,
link |
as soon as it's, it's not obviously simple, it will be as sophisticated as anything. And so
link |
that has the implication that, you know, rule 30, you know, our brains, other things in physics,
link |
they're all ultimately equivalent in the computations they can do. And that's what leads to
link |
this computational irreducibility idea, because the reason we don't get to jump ahead, you know,
link |
and outthink rule 30, is because we're just computationally equivalent to rule 30. So we're
link |
kind of just both just running computations that are the same sort of raw, the same level of
link |
computation, so to speak. So that's kind of the, the idea there. And the question, I mean, it's,
link |
it's like, the, you know, in, in the science fiction version would be, okay, somebody says,
link |
we just need more servers, get us more servers. The way to get even more servers is, turn the whole
link |
planet into a bunch of microservers. And that that's, that's where it starts. And so the question of,
link |
you know, computational equivalence principle of computational equivalence is, well, actually,
link |
you don't need to build those custom servers. Actually, you can, you can just use natural
link |
computation to compute things, so to speak, you can use nature to compute, you don't need to have
link |
done all that engineering. And it's kind of the, it's kind of feels a little disappointing that
link |
you say, we're going to build all these servers, we're going to do all these things, we're going
link |
to make, you know, maybe we're going to have human consciousness uploaded into, you know,
link |
some elaborate digital environment. And then you look at that thing, and you say it's got electrons
link |
moving around, just like in a rock. And then you say, well, what's the difference? And the principle
link |
of computational equivalence says, there isn't, at some level, a fundamental, you know, you can't
link |
say mathematically, there's a fundamental difference between the rock that is the future of human
link |
consciousness, and the rock that's just a rock. Now, what I've sort of realized with this kind of
link |
consciousness thing is, there is, there is an aspect of this that seems to be more special,
link |
that isn't, and for example, something I haven't really teased apart properly, is when it comes to
link |
something like the weather and the weather having a mind of its own or whatever, or your average,
link |
you know, pulsar magnetosphere acting like a sort of intelligent thing. How does that relate to,
link |
you know, how, how does, how is that, that entity related to the kind of consciousness that we have
link |
and sort of what would the world look like, you know, to the weather? If we think about the weather
link |
as a mind, what will it perceive? What will it laws, its laws of physics be? I don't really know.
link |
Because it's very parallel. It's very parallel, among other things. And it, it, it's not obvious.
link |
I mean, this is a really kind of mind bending thing, because we've got to try and imagine
link |
where, you know, we've got to try and imagine a parsing of the universe different from the one
link |
we have. And by the way, when we think about extraterrestrial intelligence and so on,
link |
I think that's kind of the key thing is, you know, we've always assumed, I've always assumed,
link |
okay, the extraterrestrials, at least they have the same physics, we all live in the same universe,
link |
they've got the same physics. But actually, that's not really right, because the extraterrestrials
link |
could have a completely different way of parsing that the universe. So it's as if, you know,
link |
there could be for all we know, right here in this room, you know, in the, in the details of the
link |
motion of these gas molecules, there could be an amazing intelligence that we were like, but we
link |
have no way of we're not parsing the universe in the same way. If only we could parse the
link |
universe in the right way, you know, immediately this amazing thing that's going on and this,
link |
you know, huge culture that's developed and all that kind of thing would be obvious to us, but
link |
it's not because we have our particular way of parsing the universe.
link |
Would that thing also have us agency? I don't know the right word to use, but something like
link |
consciousness, but a different kind of consciousness?
link |
I think it's a question of just what you mean by the word, because I think that the, you know,
link |
this notion of consciousness and the, okay, so some people think of consciousness as sort of a key
link |
aspect of it is that we feel that the sort of a feeling of, that we exist in some way, that we
link |
have this intrinsic feeling about ourselves. You know, I suspect that any of these things would
link |
also have an intrinsic feeling about themselves. I've been sort of trying to think recently
link |
about constructing an experiment about what if you were just a piece of a cellular automaton,
link |
let's say, you know, what would your feeling about yourself actually be? And, you know,
link |
can we put ourselves in the, in the shoes, in the cells of the cellular automaton, so to speak?
link |
Can we, can we get ourselves close enough to that, that we could have a sense of what the world
link |
would be like if you were operating in that way? And it's a little difficult because, you know,
link |
you have to not only think about what are you perceiving, but also what's actually going on
link |
in your brain. And our brains do what they actually do. And they don't, it's, you know,
link |
I think there might be some experiments that are possible with, with, you know, neural nets and so
link |
on, where you can have something where you can at least see in detail what's happening inside the
link |
system. And I've been sort of one of the, one of my projects to think about is, is there a way of
link |
kind of, kind of getting a sense, kind of from inside the system about what its view of the world
link |
is and how it, how it, you know, can, can we make a bridge? See, the main issue is this,
link |
what, where, you know, it's a, it's a sort of philosophically difficult thing because
link |
it's like, we do what we do, we understand ourselves, at least to some extent.
link |
We humans understand ourselves.
link |
That's correct. And, but yet, okay, so what are we trying to do? For example, when we are trying
link |
to make a model of physics, what are we actually trying to do? Because, you know, you say, well,
link |
can we work out what the universe does? Well, of course, we can, we just watch the universe,
link |
the universe does what it does. But what we're trying to do when we make a model of physics
link |
is we're trying to get to the point where we can tell a story to ourselves that we understand
link |
that is also a representation of what the universe does. So it's this kind of, you know,
link |
can we make a bridge between what we humans can understand in our minds and what the universe
link |
does. And in a sense, you know, a large part of my kind of life efforts have been devoted to
link |
making computational language, which kind of is a bridge between what is possible in the
link |
computational universe, and what we humans can conceptualize and think about in a sense what,
link |
you know, when I built Wolfman language and our whole sort of computational language story,
link |
it's all about how do you take sort of raw computation and this ocean of computational
link |
possibility, and how do we sort of represent pieces of it in a way that we humans can understand
link |
and that map on to things that we care about doing. And in a sense, when you add physics,
link |
you're adding this other piece where we can, you know, mediated by computer,
link |
can we get physics to the point where we humans can understand something about what's
link |
happening in it. And when we talk about an alien intelligence, it's kind of the same story. It's
link |
like, is there a way of mapping what's happening there onto something that we humans can understand?
link |
And, you know, physics, in some sense, is like our exhibit one of the story of alien intelligence.
link |
It's a, you know, it's an alien intelligence in some sense. And what we're doing in making a
link |
model of physics is mapping that onto something that we understand. And I think, you know, a lot
link |
of these other things that have I've recently been kind of studying, whether it's molecular
link |
biology, other kinds of things, which we can talk about a bit. Those are other cases where we're,
link |
in a sense, trying to, again, make that bridge between what we humans understand
link |
and sort of the natural language of that sort of alien intelligence in some sense.
link |
When you're talking about just to backtrack a little bit about cellular automata,
link |
being able to, what's it like to be a cellular automata in the way that's equivalent to what
link |
is it like to be a conscious human being? How do you approach that? So is it looking at some
link |
subset of the cellular automata, asking questions of that subset, like how the world is perceived,
link |
how you, as that subset, like for that local pocket of computation, what are you able to say
link |
about the broader cellular type? And that somehow then can give you a sense of how to step outside
link |
of that cellular automata. Right. But the tricky part is that that little subset, it's what it's
link |
doing is it has a view of itself. And the question is, how do you get inside it? It's like, you know,
link |
when we, with humans, right, it's like, we can't get inside each other's consciousness.
link |
That doesn't really, you know, that doesn't really even make sense. It's like, there is an
link |
experience that somebody is having, but you can perceive things from the outside, but sort of
link |
getting inside it, it doesn't quite make sense. And for me, these sort of philosophical issues,
link |
and this one I have not untangled. So let's be, for me, the thing that has been really
link |
interesting in thinking through some of these things is, you know, when it comes to questions
link |
about consciousness or whatever else, it's like, when I can run a program and actually
link |
see pictures and, you know, make things concrete, I have a much better chance to understand what's
link |
going on than when I'm just trying to reason about things in a very abstract way.
link |
Yeah, but there may be a way to map the program to your conscious experience. So for example,
link |
when you play a video game, you do a first person shooter, you walk around inside this entity.
link |
It's a very different thing than watching this entity. So if you can somehow connect,
link |
more and more connect this, this full conscious experience to the subset of the cellular automata.
link |
Yeah, it's something like that. But the difference in the first person shooter thing is there's
link |
still your brain and your memory is still remembering, you know, you, you still have,
link |
it's hard to, I mean, again, what one's going to get, one is not going to actually be able to
link |
be the cellular automaton. One's going to be able to watch what the cellular automaton does.
link |
But this is the frustrating thing that I'm trying to understand, you know, how to,
link |
how to think about being it, so to speak.
link |
Okay, so like in virtual reality, there's a concept of immersion, like with anything,
link |
with video game, with books, there's a concept of immersion. It feels like over time,
link |
if the virtual reality experience is well done, and maybe in the future it'll be extremely well
link |
done, the immersion leads you to feel like you mentioned memories, you forget that you even
link |
ever existed outside that experience. It's so immersive. I mean, you could argue sort of mathematically
link |
that you can never truly become immersed, but maybe you can. I mean, why can't you merge with
link |
the cellular automaton? I mean, aren't you just part of the same fabric? Why can't you just like...
link |
Well, that's a good question. I mean, so let's imagine the following scenario, let's imagine...
link |
Then can you return?
link |
But then can you return back?
link |
Well, yeah, right. I mean, it's like, let's imagine you've uploaded, you know, your brain
link |
is scanned, you've got every synapse, you know, mapped out, you upload everything about you,
link |
the brain simulator, you upload the brain simulator, and the brain simulator is basically,
link |
you know, some glorified cellular automaton. And then you say, well, now we've got an answer to
link |
what does it feel like to be a cellular automaton? It feels just like it felt to be ordinary you,
link |
because they're both computational systems, and they're both, you know, operating in the same way.
link |
So in a sense, but I think there's somehow more to it, because in that sense, when you're just
link |
making a brain simulator, it's just, you know, we're just saying there's another version of our
link |
consciousness. The question that we're asking is, if we tease away from our consciousness,
link |
and get to something that is different, how do we make a bridge to understanding what's going on
link |
there? And, you know, there's a way of thinking about this. Okay, so this is coming on to sort
link |
of questions about the existence of the universe and so on. But one of the things is there's this
link |
notion that we have of rural space. So we have this idea of this physical space, which is, you
link |
know, something you can move around in that's associated with the actual, the extent of the
link |
spatial hypergraph, then there's what we call branchial space, the space of quantum branches.
link |
So in this thing we call the multiway graph of all of this sort of branching histories,
link |
there's this idea of a kind of space where instead of moving around in physical space,
link |
you're moving from history to history, so to speak, from one possible history to another
link |
possible history. And that's kind of a different kind of space that is the space in which quantum
link |
mechanics plays out. Quantum mechanics, like for example, oh, something like, I think we're slowly
link |
understanding things like destructive interference in quantum mechanics, that what's happening is
link |
branchial space is associated with phase and quantum mechanics. And what's happening is the
link |
two photons that are supposed to be interfering and destructively interfering are winding up
link |
at different ends of branchial space. And so us as these poor observers that are trying to,
link |
that have branching brains that are trying to conflate together these different threads of history
link |
and say, we've really got a consistent story that we're telling here, we're really knitting
link |
together these threads of history by the time the two photons wound up at opposite ends of
link |
branchial space, we just can't knit them together to tell a consistent story. So for us, that's
link |
sort of the analog of destructive interference. Got it. And then there's rural space too,
link |
which is the space of rules. Yes. Well, that's another level up. So there's the question.
link |
Actually, I do want to mention one thing, because it's something I've realized in recent times,
link |
and it's, I think it's really, really kind of cool, which is about time dilation and
link |
relativity. And it kind of helps to understand, it's something that kind of helps in understanding
link |
what's going on. So according to relativity, if you have a clock, it's taking at a certain rate,
link |
you send it in a spacecraft that's going at some significant fraction of the speed of light,
link |
to you as an observer at rest, that clock that's in the spacecraft will seem to be ticking much
link |
more slowly. And so in other words, it's kind of like the twin who goes off to Alpha Centauri
link |
and goes very fast will age much less than the twin who's on Earth that is just hanging out
link |
where they're hanging out. Okay, why does that happen? Okay, so it has to do with what motion is. So
link |
in in our models of physics, what is motion? Well, when you move from somewhere to somewhere,
link |
it's you're having to sort of recreate yourself at a different place in space. When you exist at
link |
a particular place, and you just evolve with time, you're again, you're updating yourself,
link |
you're you're following these rules to update what happens. Well, so the question is when you
link |
have a certain amount of computation in you, so to speak, when there's a certain amount,
link |
you know, you're computing the universe is computing at a certain rate, you can either use
link |
that computation to work out sitting still where you are, what's going to happen successfully in
link |
time, or you can use that computation to recreate yourself as you move around the universe. And so
link |
time dilation ends up being, it's really cool, actually, that this is explainable in a in a way
link |
that isn't just imagine the mathematics of relativity. But that time dilation is a story
link |
of the fact that as you kind of are recreating yourself as you move, you are using up some
link |
of your computation. And so you don't have as much computation left over to actually work out what
link |
happens progressively with time. So that means that time is running more slowly for you, because
link |
it is you're you're using up your computation, your clock can't tick as quickly, because every
link |
tick of the clock is using up some computation, but you already use that computation up on moving at,
link |
you know, half the speed of light or something. And so that's that's why time dilation happens.
link |
And so you can you can start so it's kind of interesting that one can sort of get an intuition
link |
about something like that, because it has seemed like just a mathematical fact about the mathematics
link |
of special relativity and so on. Well, for me, it's a little bit confusing what the you in that
link |
picture is, because you're using up computation. Okay, so so we're simply saying the entity is
link |
updating itself according to the way that the universe updates itself. And the question is,
link |
you're, you know, those updates, let's imagine the you as a clock. Okay. And the clock is, you
link |
know, there's all these little updates, the hypergraph and a sequence of updates cause the
link |
pendulum to swing back the other way, and then swing back, swinging back and forth. Okay. And
link |
all of the all of those updates are contributing to the motion of, you know, the pendulum going
link |
back and forth or the little oscillator moving, whatever it is. Okay. But but then the alternative
link |
is that sort of situation one, where the thing is at rest, situation two, where it's kind of moving
link |
the the what's happening is, it is having to recreate itself at every, at every moment,
link |
the thing is going to have to do the computations to be able to sort of recreate itself at a
link |
different position in space. And that's kind of the intuition behind. So it's either going to
link |
spend its computation, recreating itself at a different position in space, or it's going to
link |
spend its computation doing the sort of doing the updating of the, you know, of the ticking of the
link |
clock, so to speak. So the more updating is doing the less the ticking of the clock updates doing.
link |
That's right. The more it has having to update because of motion, yeah, the less it can update
link |
the clock. So that that's, I mean, obviously, there's a there's a sort of mathematical version
link |
of it that relates to how it actually works in relativity. But that's kind of, to me, that
link |
was sort of exciting to me that it's possible to have a really mechanically explainable story there
link |
that that isn't, and it's similarly in quantum mechanics, this notion of branching brains,
link |
perceiving branching universes. To me, that's getting towards a sort of mechanically explainable
link |
version of what happens in quantum mechanics, even though it's a little bit mind bending,
link |
to see, you know, these things about under what circumstances can you successfully knit together
link |
those different threads of history, and when do things sort of escape, and those kinds of things.
link |
But the, you know, the thing about this physical space and physical space, the the main sort of
link |
big theory is general relativity, the theory of gravity. And that tells you how things move in
link |
physical space. In branching space, the big theory is the Feynman path integral, which,
link |
it turns out, tells you essentially how things move in quantum, in the space of quantum phases.
link |
So it's kind of like motion in branching space. And it's kind of a fun thing to start thinking
link |
about what, oh, you know, all these things that we know in physical space, like event horizons
link |
and black holes and so on, what are the analogous things in branching space, for example, the speed
link |
of light, what's the analog of the speed of light in branching space, it's the maximum speed of
link |
quantum entanglement. So the speed of light is a flash bulb goes off here, what's the maximum
link |
rate at which the effect of that flash bulb is detectable moving away in space. So similarly,
link |
in branching space, something happens. And the question is, how far in this branching space,
link |
in the space of quantum states, how far away can that get within a certain period of time.
link |
And so there's this notion of a maximum entanglement speed. And that might be observable,
link |
that's the thing we've been sort of poking at, is might there be a way to observe it,
link |
even in some atomic physics kind of situation. Because one of the things that's weird in quantum
link |
mechanics is we're, you know, when we study quantum mechanics, we mostly study it in terms
link |
of small numbers of particles, you know, this electron does this, this thing on an ion trap
link |
does that and so on. But when we deal with large numbers of particles, kind of all bets are off,
link |
it's kind of too complicated to deal with quantum mechanics. And so what ends up happening is,
link |
so this question about maximum entanglement speed and things like that may actually play
link |
in one of these, in the sort of story of many body quantum mechanics, and even have some suspicions
link |
about things that might happen, even in one of the things I realized I'd never understood,
link |
and it's kind of embarrassing, but I think I now understand a little better, is when you have chemistry
link |
and you have quantum mechanics, it's like, well, there's two carbon atoms as this molecule and
link |
we do a reaction, and we draw a diagram and we say this carbon atom ends up in this place.
link |
And it's like, but wait a minute, in quantum mechanics, nothing ends up in a definite place.
link |
There's always just some wave function for this to happen. How can it be the case
link |
that we can draw these reasonable, it just ended up in this place. And you have to kind of say,
link |
well, the environment of the molecule effectively made a bunch of measurements on the molecule
link |
to keep it kind of classical. And that's a story that has to do with
link |
this whole thing about, you know, measurements have to do with this idea of, you know, can we
link |
conclude that something definite happened? Because in quantum mechanics, the intrinsic
link |
quantum mechanics, the mathematics of quantum mechanics is all about, they're just these
link |
amplitudes for different things to happen. Then there's this thing of, and then we make a measurement,
link |
and we conclude that something definite happened. And that has to do with this thing,
link |
I think, about sort of moving about knitting together these different threads of history
link |
and saying, this is now something where we can definitively say something definite happened.
link |
In the traditional theory of quantum mechanics, it's just like, you know, after you've done
link |
all this amplitude computation, then this big hammer comes down, and you do a measurement,
link |
and it's all over. And that's been very confusing. For example, in quantum computing,
link |
it's been a very confusing thing. Because when you say, you know, in quantum computing,
link |
the basic idea is you're going to use all these separate threads of computation, so to speak,
link |
to do all the different parts of, you know, try these different factors for an integer or
link |
something like this. And it looks like you can do a lot because you've got all these different
link |
threads going on. But then you have to say, well, at the end of it, you've got all these threads,
link |
and every thread came up with a definite answer, but we got to conflate those together to figure
link |
out a definite thing that we humans can take away from it, a definite so the computer actually
link |
produced this output. So having this branchial space and this hypergraph model of physics,
link |
do you think it's possible to then make predictions that are definite about many body
link |
quantum mechanical systems? Is that the hope? I think it's likely, yes. But I don't, you know,
link |
this is every one of these things, when you, when you go from the underlying theory, which is
link |
complicated enough, and it's, I mean, the theory at some level is beautifully simple. But as soon
link |
as you start actually trying to, it's this whole question about how do you bridge it to things
link |
that we humans can talk about? It gets really complicated. And this thing about actually getting
link |
it to a definite prediction about, you know, definite thing you can say about chemistry
link |
or something like this, you know, that's just a lot of work. So I'll give you an example.
link |
There's a thing called the quantum Zeno effect. So the idea is, you know, quantum stuff happens,
link |
but then if you make a measurement, you're kind of freezing time in quantum mechanics. And so it
link |
looks like there's a possibility that with sort of the relationship between the quantum Zeno effect
link |
and the way that many body quantum mechanics works and so on, maybe just conceivably, it may be
link |
possible to actually figure out a way to measure the maximum entanglement speed. And the reason we
link |
can potentially do that is because the systems we deal with in terms of atoms and things, they're
link |
pretty big, you know, a mole of atoms is, you know, is a lot of atoms. And, you know, but it isn't a
link |
very, you know, it's something where to get, you know, when we're dealing with how can you see 10
link |
to the minus 100, so to speak, well, by the time you've got, you know, 10 to the 30th atoms, you're
link |
not, you know, you're within a little bit closer striking distance of that. It's not like, oh,
link |
we've just got, you know, two atoms, and we're trying to see down to 10 to the minus 100 meters
link |
or whatever. So I don't know how it will work, but this is a, this is a potential direction.
link |
And if you can tell, by the way, if we could measure the maximum entanglement speed, we would
link |
know the elementary length. These are all related. So if we got that one number, we just need one
link |
number, if we can get that one number, we can, you know, the theory has no parameters anymore.
link |
And, you know, there are other places, well, there's another hope for doing that,
link |
is in cosmology. In this model, one of the features is the universe is not fixed dimensional.
link |
I mean, we think we live in three dimensional space, but this hypergraph doesn't have any
link |
particular dimension. It can emerge as something which on an approximation, it's as if, you know,
link |
you say, what's the volume of a sphere in the hypergraph where a sphere is defined as
link |
how many nodes do you get to when you go a distance r away from a given point?
link |
And you can say, well, if I get to about r cube nodes, when I go a distance r away in the
link |
hypergraph, then I'm living roughly in three dimensional space. But you might also get to r
link |
to the point, you know, 2.92, you know, for some value of r in, you know, as r increases,
link |
that might be the sort of fit to what happens. And so one of the things we suspect is that
link |
the very early universe was essentially infinite dimensional. And that as the universe expanded,
link |
it became lower dimensional. And so one of the things that is another little sort of point
link |
where we think there might be a way to actually measure some things is dimension fluctuations
link |
in the early universe. That is, is there a, is there leftover dimension fluctuation of
link |
at the time of the cosmic microwave background, 100,000 years or something after the beginning
link |
of the universe? Is it still the case that there are, there were pieces of the universe
link |
that didn't have dimension three, that had dimension 3.01 or something? And can we tell that?
link |
Is that possible to observe fluctuations in dimensions? I don't even know what that entails.
link |
Okay, so the question, which should be an elementary exercise in electrodynamics,
link |
except it isn't, is understanding what happens to a photon when it propagates through 3.01
link |
dimensional space. So for example, the inverse square law is a consequence of the, you know,
link |
the surface area of a sphere is proportional to R squared. But if you're not in three dimensional
link |
space, the surface area of sphere is not proportional to R squared, it's R to the whatever, 2.01
link |
or something. And so that means that I think when you kind of try and do optics, you know,
link |
a common principle in optics is Huygens principle, which basically says that every piece of a
link |
wave front of light is a source of new spherical waves. And those spherical waves, if they're
link |
different dimensional spherical waves, will have other characteristics. And so there will be bizarre
link |
optical phenomena, which we haven't figured out yet. So you're looking for some weird
link |
photon trajectories that designate that it's 3.01 dimensional space? Yeah. Yeah, that would be an
link |
example of, I mean, you know, there are there are only a certain number of things we can measure
link |
about photons, you know, we can measure their polarization, we can measure their frequency,
link |
we can measure their direction, those kinds of things. And, you know, how that all works out.
link |
And, you know, in the current models of physics, you know, it's been hard to explain how the
link |
universe manages to be as uniform as it is. And that's led to this inflation idea that to the
link |
great annoyance of my then collaborator, I we had, we figured out in like 1979, we had this
link |
realization that you could get something like this. But it seemed implausible that that's the
link |
way the universe worked. So we put in a footnote. And that was, so that's a, but in any case, I've
link |
never really completely believed it. But this, that's an idea for how to sort of puff out the
link |
universe faster than the speed of light, early moments of the universe, that that's the sort of
link |
the inflation idea. And that you can somehow explain how the universe manages to be as uniform as it
link |
is. In our model, this turns out to be much more natural, because the universe just starts very
link |
connected, the hypergraph is not such that the ball that you grow starting from a single point has
link |
volume r cubed, it might have volume r to the 500 or r to the infinity. And so that means that you
link |
sort of naturally get this much higher degree of connectivity and uniformity in the universe.
link |
And then the question is, this is sort of the mathematical physics challenge is in the standard
link |
theory of the universe, there's the Friedman, Roberts and Walker universe, which is the kind
link |
of standard model where the universe is isotropic and homogeneous. And you can then work out the
link |
equations of general relativity, and you can figure out how the universe expands. We would like to do
link |
the same kind of thing, including dimension change. This is just difficult mathematical physics.
link |
I mean, the fundamental reason it's difficult, when people invented calculus 300 years ago,
link |
calculus was the story of understanding change and change as a function of a variable.
link |
And so people study univariate calculus, they study multivariate calculus, it's one variable,
link |
it's two variables, three variables, but whoever studied 2.5 variable calculus turns out nobody.
link |
It turns out that, but what we need to have to understand these fractional dimensional
link |
spaces, which don't work like, well, they're spaces where the effective dimension is not
link |
an integer. So you can't apply the tools of calculus and natural and easily to fractional
link |
So somebody has to figure out how to do that. Yeah, we're trying to figure this out. I mean,
link |
it's very interesting. I mean, it's very connected to very frontier issues in mathematics,
link |
it's very beautiful. So is it possible, we're dealing with a scale that's so,
link |
so much smaller than our human scale, is it possible to make predictions versus explanations?
link |
Do you have a hope that with this hypergraph model, you'd be able to make predictions?
link |
That that could be validated with a physics experiment, predictions that couldn't have
link |
been done or weren't done otherwise. In which domain do you think?
link |
Okay, so they're going to be cosmology ones to do with dimension fluctuations in the universe.
link |
That's a very bizarre effect. Dimension fluctuation is just something nobody ever looked for that.
link |
If anybody sees dimension fluctuation, that's a huge flag, that's something like our model
link |
is going on. And how one detects that, that's a problem of traditional physics,
link |
in a sense of what's the best way to actually figure that out. And for example, that's one,
link |
there are all kinds of things one can imagine. I mean, there are things that in black hole mergers,
link |
it's possible that there will be effects of maximum entanglement speed in large black hole
link |
mergers. That's another possible thing. And all of that is detected through,
link |
like what, do you have a hope for a LIGO type of situation, like that's gravitational waves?
link |
Yeah, or alternatively, I mean, I think it's, look, figuring out experiments is like
link |
figuring out technology inventions. That is, you've got a set of raw materials,
link |
you've got an underlying model, and now you've got to be very clever to figure out,
link |
what is that thing I can measure that just somehow leverages into the right place.
link |
And we've spent less effort on that than I would have liked, because one of the reasons is that
link |
I think that the physicists who've been working on our models, we've now lots of physicists,
link |
actually, it's very, very nice. It's kind of, it's one of these cases where I'm almost,
link |
I'm really kind of pleasantly surprised that the sort of absorption of the things we've done
link |
has been quite rapid and quite sort of very positive.
link |
So it's a camber and explosion of physicists too, and not just ideas.
link |
Yes, I mean, you know, a lot of what's happened, that's really interesting. And again, not what
link |
I expected is there are a lot of areas of sort of very elaborate, sophisticated mathematical
link |
physics, whether that's causal set theory, whether it's higher category theory, whether it's
link |
categorical quantum mechanics, all sorts of elaborate names for these things, spin networks,
link |
perhaps, you know, causal dynamical triangulations, all kinds of names of these fields. And these
link |
fields have a bunch of good mathematical physicists in them, who've been working for decades in
link |
these particular areas. And the question is, but they've been building these mathematical
link |
structures. And the mathematical structures are interesting, but they don't typically sit on
link |
anything. They're just mathematical structures. And I think what's happened is our models provide
link |
kind of a machine code that lives underneath those models. So a typical example, this is
link |
a due to Jonathan Gorod, who's one of the key people who's been working on a project.
link |
This is in, okay, so I'll give you an example just to give a sense of how these things connect.
link |
This is in causal set theory. So the idea of causal set theory is there are, in space time,
link |
we imagine that there's space and time, it's a three plus one dimensional, you know, set up,
link |
we imagine that there are just events that happen at different times and places in space and time.
link |
And the idea of causal set theory is the only thing you say about the universe is there are
link |
a bunch of events that happen sort of randomly at different places in space and time. And then
link |
the whole sort of theory of physics has to be to do with this graph of causal relationships
link |
between these randomly thrown down events. So they've always been confused by the fact that
link |
to get even Lorentz invariance, even relativistic invariance, you need a very special way to throw
link |
down those events. And they've had no natural way to understand how that would happen. So what
link |
Jonathan figured out is that, in fact, from our models, they instead of just generating events at
link |
random, our models necessarily generate events in some pattern in space time effectively, that
link |
then leads to Lorentz invariance and relativistic invariance and all those kinds of things. So it's
link |
a place where all the mathematics that's been done on, well, we just have a random collection of
link |
events. Now, what consequences does that have in terms of causal set theory and so on, that can
link |
all be kind of wheeled in now that we have some different underlying foundational idea for what
link |
the particular distribution of events is as opposed to just what we throw down random events.
link |
And so that's a typical sort of example of what we're seeing in all these different areas of kind
link |
of how you can take really interesting things that have been done in mathematical physics
link |
and connect them. And it's really kind of beautiful because the abstract models we have
link |
just seem to plug into all these different very interesting, very elegant abstract ideas. But
link |
we're now giving sort of a reason for that to be the way, a reason for one to care. I mean,
link |
it's like saying, you can think about computation abstractly. You can think about, I don't know,
link |
combinators or something as abstract computational things. And you can sort of do all kinds of
link |
study of them. But it's like, why do we care? Well, okay, Turing machines are a good start
link |
because you can kind of see that sort of mechanically doing things. But when we actually
link |
start thinking about computers, computing things, we have a really good reason to care. And this
link |
is sort of what we're what we're providing, I think, is a reason to care about a lot of these
link |
areas of mathematical physics. So that's been, that's been very nice. So I'm not sure we've
link |
ever got to the question of why does the universe exist at all?
link |
No, let's talk about that. Yes.
link |
So we're, it's not the simplest question in the world. So it takes a few steps to get to it.
link |
And it's nevertheless even surprising that you can even begin to answer this question,
link |
as you were saying. I'm very surprised. So the next thing to perhaps understand is this idea
link |
of rural space. So we've got kind of physical space, we've got bronchial space, the space of
link |
possible quantum histories. And now we've got another level of kind of abstraction, which is
link |
rural space. And here's the, here's where that comes from. So you say, okay, you say we've got
link |
this model for the universe, we've got a particular rule, and we run this rule, and we get the
link |
universe. Okay, so that's, that's interesting. Why that rule? Why not another rule? And so that
link |
confused me for a long time. And I realized, well, actually, what if the thing could be
link |
using all possible rules? What if at every step, in addition to saying apply a particular rule
link |
at all places in this hypergraph, one could say, just take all possible rules and apply
link |
all possible rules at all possible places in this hypergraph. Okay. And then you make this
link |
rural multiway graph, which both is all possible histories for a particular rule and all possible
link |
rules. So the next thing you'd say is, how can you get anything reasonable? How can anything,
link |
you know, real come out of the set of all possible rules applied in all possible ways?
link |
Okay, this is a subtle thing. So which I haven't fully untangled. The there is this object,
link |
which is the result of running all possible rules in all possible ways. And you might say,
link |
if you're running all possible rules, why can't everything possible happen? Well, the answer is
link |
because when you there's sort of this entanglement that occurs. So let's say that you have a lot
link |
of different possible initial conditions, a lot of different possible states, then you're applying
link |
these different rules. Well, some of those rules can end up with the same state. So it isn't the
link |
case that you can just get from anywhere to anywhere. There's this whole entangled structure
link |
of what can lead to what and there's a definite structure that's produced. I think I'm going
link |
to call that definite structure, the RULIAD, the limit of the limits of kind of all possible rules
link |
being applied in all possible ways. And you're saying that structure is finite, so that somehow
link |
connects to maybe a similar kind of thing as like causal invariance. Well, RULIAD necessarily has
link |
causal invariance. That's a feature of that's just a mathematical consequence of essentially
link |
using all possible rules, plus universal computation gives you the fact that from any
link |
diverging paths you can always, the paths will always convert.
link |
But does that necessarily infer that the RULIAD is a finite?
link |
In the end, it's not necessarily finite. I mean, it's just like the history of the universe may
link |
not be finite. The history of the universe, time may keep going forever. You can keep running the
link |
computations of the RULIAD and you'll keep spewing out more and more and more structure. It's like
link |
time doesn't have to end. But the issue is there are three limits that happen in this RULIAD object.
link |
One is how long you run the computation for. Another is how many different rules you're
link |
applying. Another is how many different states you start from. And the mixture of those three
link |
limits, I mean, this is just mathematically a horrendous object. And what's interesting about
link |
this object is the one thing that does seem to be the case about this object is it connects
link |
with ideas in higher category theory. And in particular, it connects to some of the 20th
link |
century's most abstract mathematics done by this chap, growth and deke. Growth and deke had a thing
link |
called the infinity group void, which is closely related to this RULIAD object. Although the details
link |
of the relationship, you know, I don't fully understand yet. But I think that what's interesting
link |
is this thing that is sort of this very limiting object. So okay, so a way to think about this,
link |
that again, will take us into another direction, which is the equivalence between physics and
link |
mathematics. The way that, well, let's see, maybe this is just to give a sense of this kind of
link |
group void and things like that, you can think about in mathematics, you can think you have
link |
certain axioms, they're kind of like atoms. And you, well, actually, let's say, let's talk about
link |
mathematics for a second. So what is mathematics? What is what is it made of, so to speak? Mathematics,
link |
there's a bunch of statements like, for addition, x plus y is equal to y plus x, that's a statement
link |
of mathematics. Another statement would be, you know, x squared minus one is equal to x plus
link |
one x minus one. There are infinite number of these possible statements of mathematics.
link |
So it's not, I mean, it's not just I guess a statement, but with x plus y, it's a rule that
link |
you can, I mean, you think of it as a rule. It's a, it is a rule. It's also just a thing that is
link |
true in mathematics. The statement is true. Right. And what you can imagine is you imagine just
link |
laying out this giant kind of ocean of all statements, well, actually, you first start,
link |
okay, this is where this was segwaying into a different thing. Let me not go in this direction
link |
for a second. Let's not go to meta mathematics just yet. Yeah, we'll maybe get to meta mathematics,
link |
but it's, so let me not, let me explain the groupoid and things later. Yes. But so let's
link |
come back to the universe, always a good place to be in. So what does the universe have to do
link |
with the rule of the all space and how that's possibly connected to why the thing exists at all
link |
and why there's just one of them? Yes. Okay. So here's the point. So the thing that had confused
link |
me for a long time was, let's say we get the rule for the universe, we hold it in our hand,
link |
we say, this is our universe. Then the immediate question is, well, why isn't it another one?
link |
And, you know, that's kind of the, you know, the, the sort of the lesson of Copernicus is,
link |
we're not very special. So how come we got universe number 312 and not universe quadriline,
link |
quadriline, quadriline. And I think the resolution of that is the realization that
link |
there, that the universe is running all possible rules. So then you say, well, how on earth do we
link |
perceive the universe to be running according to a particular rule? How do we perceive definite
link |
things happening in the universe? Well, it's the same story. It's the observer, there is a reference
link |
frame that we are picking in this rural space. And that that is what determines our perception
link |
of the universe. With our particular sensory information and so on, we are parsing the universe
link |
in this particular way. So here's the way to think about it. In, in, in physical space,
link |
we live in a particular place in the universe. And, you know, we could live on Alpha Centauri,
link |
but we don't, we live here. And similarly, in rural space, we could live in many different
link |
places in rural space, but we happen to live here. And what does it mean to live here? It means
link |
we have certain sensory input. We have certain ways to parse the universe. Those are our
link |
interpretation of the universe. What would it mean to travel in rural space? What it basically
link |
means is that we are successively interpreting the universe in different ways. So in other words,
link |
to be at a different point in rural space is to have a different, in a sense, a different
link |
interpretation of what's going on in the universe. And we can imagine even things like an analog of
link |
the speed of light as the maximum speed of translation in rural space and so on.
link |
So wait, what's the interpretation? So rural space, we, I'm confused by the we and the
link |
interpretation and the universe. I thought moving about in rural space changes the way the universe
link |
is, is the way we would perceive it. The way that that ultimately has to do with the perception.
link |
So it doesn't real, rural space is not somehow changing, like,
link |
branching into another universe, something like that. No, I mean, the point is that the whole
link |
point of this is the Rouliat is sort of the encapsulated version of everything that is the
link |
universe running according to all possible rules. Yeah, we think of our universe, the observable
link |
universe as its thing. So we're a little bit loose with the word universe then, because wouldn't the
link |
Rouliat potentially encapsulate a very large number, like combinatorially large, maybe infinite
link |
set of what we human physicists think of as universes.
link |
That's an interesting, interesting parsing of the word universe, right? Because what we're
link |
saying is just as we're at a particular place in physical space, we're at a particular place in
link |
rural space. At that particular place in rural space, our experience of the universe is this,
link |
just as if we lived at the center of the galaxy, our universe, our experience of the universe
link |
will be different from the one it is, given where we actually live. And so in what we're saying is
link |
when you might say, I mean, in a sense, this Rouliat is sort of a super universe, so to speak.
link |
But it's all entangled together. It's not like you can separate out, you can say,
link |
let me, it's like when we take a reference, okay, it's like our experience of the universe is
link |
based on where we are in the universe. We could imagine moving to somewhere else in the universe,
link |
but it's still the same universe. So there's not like universes existing in parallel?
link |
No. Because, and the whole point is that if we were able to change our interpretation of
link |
what's going on, we could perceive a different reference frame in this Rouliat.
link |
Yeah, but that's not, that's just, yeah, that's the same Rouliat. That's the same universe.
link |
You're just moving about. These are just coordinates in the universe.
link |
So the way that's, the reason that's interesting is, imagine the extraterrestrial intelligence,
link |
so the alien intelligence, we should say. The alien intelligence might live on Alpha Centauri,
link |
but it might also live at a different place in rural space.
link |
It can live right here on Earth. It just has a different reference frame that
link |
includes a very different perception of the universe. And then because that rural space is
link |
very large, I mean... Do we get to communicate with them? Right, that's...
link |
Yeah, but it's also, well, one thing is how different the perception of the universe could be.
link |
I think it could be bizarrely, unimaginably, completely different. And I mean, one thing to
link |
realize is, even in kind of things I don't understand well, I know about the kind of
link |
Western tradition of understanding science and all that kind of thing. And you talk to people
link |
who say, well, I'm really into some Eastern tradition of this, that and the other. And
link |
it's really obvious to me how things work. I don't understand it at all. But it is not obvious,
link |
I think, with this kind of realization that there's these very different ways to interpret
link |
what's going on in the universe. That kind of gives me at least... It doesn't help me to understand
link |
that different interpretation, but it gives me at least more respect for the possibility that
link |
there will be other interpretations. Yeah, it humbles you to the possibility that,
link |
like, what is it? Reincarnation or all these, like, eternal recurrence with Nietzsche? Like,
link |
just these ideas? Yeah. Well, you know, the thing that I realized about a bunch of those things is
link |
that, you know, I've been sort of doing my little survey of the history of philosophy, just trying
link |
to understand, you know, what can I actually say now about some of these things? And you realize
link |
that some of these concepts, like the immortal soul concept, which, you know, I remember when I was a
link |
kid and, you know, it was kind of a lots of religion bashing type stuff of people saying, you know,
link |
well, we know about physics. Tell us how much does a soul weigh? And people are like, well,
link |
how can it be a thing if it doesn't weigh anything? Well, now we understand, you know,
link |
there is this notion of what's in brains that isn't the matter of brains, and it's something
link |
computational. And there is a sense, and in fact, it is correct that it is in some sense immortal,
link |
because this pattern of computation is something abstract that is not specific to the particular
link |
material of a brain. Now, we don't know how to extract it, you know, in our traditional scientific
link |
approach. But it's still something where it isn't a crazy thing to say there is something,
link |
it doesn't weigh anything. That's a kind of a silly question. How much does it weigh? Well,
link |
actually, maybe it isn't such a silly question in our model of physics, because the actual
link |
computational activity has has a consequence for gravity and things. But that's a very subtle
link |
you can talk about mass and energy and so on. There could be a what would you call a solitron.
link |
Yes, yes. A particle that somehow contains soleness.
link |
Yeah, right. Well, that's what, by the way, that's what Leibniz said. And, you know, one thing,
link |
I've never understood this, you know, Leibniz had this idea of monads and monodology, and he had
link |
this idea that what exists in the universe is this big collection of monads, and that the only
link |
thing that one knows about the monads is sort of how they relate to each other. It sounds awfully
link |
like hypergraphs, right? But Leibniz had really lost me at the following thing. He said, each of
link |
these monads has a soul, and each of them has a consciousness. And it's like, okay, I'm out of
link |
here. I don't understand this at all. I don't know what's going on. But I realized recently
link |
that in his day, the concept that a thing could do something could spontaneously do something,
link |
that was his only way of describing that. And so what I would now say as well is this
link |
this abstract rule that runs to Leibniz, that would have been, you know, in 1690 or whatever,
link |
that would have been kind of, well, it has a soul, it has a consciousness. And so, you know,
link |
in a sense, it's like one of these, there's no new idea under the sun, so to speak. That's, you
link |
know, that's a sort of a version of the same kinds of ideas, but couched in terms that are sort of
link |
bizarrely different from the ones that we would use today.
link |
Would you be able to maybe play devil's advocate on your conception of consciousness that like the
link |
two characteristics of it that is constrained and there's a single thread of time? Is it possible
link |
that Leibniz was onto something that the basic atom, the screwy atom of space has a consciousness?
link |
Is that, so these are just words, right? But what is there, is there some sense where consciousness
link |
is much more fundamental than you're making it seem?
link |
I don't know. I mean, that, you know, I think...
link |
Can you construct a world in which it is much more fundamental?
link |
I think that, okay, so the question would be, is there a way to think about kind of,
link |
if we sort of parse the universe down at the level of atoms of space or something,
link |
could we say, well, so that's really a question of a different point of view,
link |
a different place in real space. We're asking, you're asking the question,
link |
could there be a civilization that exists? Could there be sort of conscious entities
link |
that exist at the level of atoms of space? And what would that be like?
link |
And I think that comes back to this question of, can we, you know, what's it like to be a cellular
link |
automaton type thing? I mean, it's, you know, I'm not yet there. I don't know.
link |
I mean, I think that this is a, and I don't even know yet quite how to think about this
link |
in the sense that I was considering, you know, I'm, I never write fiction,
link |
but I haven't written it since I was like 10 years old. And my fiction, I made one attempt,
link |
which I sent to some science fiction writer friends of mine, and they told me it was terrible.
link |
So the bedtime... This is a long time ago?
link |
No, it was recently. Recently. They said it was terrible. That'd be
link |
interesting to see you write a short story based on what sounds like it's already inspiring
link |
short stories by, or stories by science fiction writers.
link |
But, but I think the interesting thing for me is, you know, in the, what does it,
link |
what is it like to be a whatever? How do you describe that? I mean, it's like,
link |
that's not a thing that you describe in mathematics, that what is it like to be such and such?
link |
Well, see, to me, when you say, what is it like to be something presumes that you're talking about
link |
a singular entity? So, yeah, like there's some kind of feeling of the entity, the stuff that's
link |
inside of it and the stuff that's outside of it. And then that's when consciousness starts making
link |
sense. But, but then it seems like that could be generalizable. If you take some subset of
link |
a cellular automata, you could start talking about what does that subset
link |
may feel. But then you can, I think you could just take arbitrary numbers of subsets. Like,
link |
to me, like you and I individually are consciousnesses, but you could also say
link |
the two of us together is a singular consciousness. Maybe, maybe, I'm not so sure about that. I think
link |
that the single thread of time thing may be pretty important. And that as soon as you start saying,
link |
there are two different threads of time, there are two different experiences. And then we have to
link |
say, how do they relate? How are they sort of entangled with each other? I mean, that may be a
link |
different story of a thing that isn't much like, what are the ants? What's it like to be an ant,
link |
where there's a sort of more collective view of the world, so to speak? I don't know. I think that,
link |
I mean, this is, I don't really have a good, I mean, my best thought is, can we turn it
link |
into a human story? It's like the question of, when we try and understand physics, can we turn
link |
that into something which is sort of a human understandable narrative? And now what's it
link |
like to be a such and such? Maybe the only medium in which we can describe that is something like
link |
fiction, where it's kind of like you're telling the life story in that setting. But this is
link |
beyond what I've yet understood how to do. Yeah, but it does seem so like with human consciousness,
link |
we're made up of cells. And there's a bunch of systems that are networked that work together
link |
that at this, at the human level, feel like a singular consciousness when you take,
link |
yes. And so maybe like an ant colony is just too low level. Sorry, an ant is too low level.
link |
Maybe you have to look at the ant colony. Yeah, I agree. There's some level at which
link |
it's a conscious being. And then if you go to the planetary scale, then maybe that's going too far.
link |
So there's a nice sweet spot for consciousness. No, I agree. I think the difficulty is that,
link |
you know, okay, so in sort of people who talk about consciousness, one of the terrible things
link |
I've realized, because I've now interacted with some of this community, so to speak,
link |
some interesting people who do that kind of thinking. But one of the things I was saying
link |
to one of the leading people in that area, I was saying that it must be kind of frustrating,
link |
because it's kind of like a poetry story. That is, many people are writing poems,
link |
but few people are reading them. So they're always these different, you know,
link |
everybody has their own theory of consciousness, and they are very non inter sort of interdiscussable.
link |
And by the way, I mean, you know, my own approach to sort of the question of consciousness,
link |
as far as I'm concerned, I'm an applied consciousness operative, so to speak, because
link |
I don't really, in a sense, the thing I'm trying to get out of it is how does it help me to understand
link |
what's a possible theory of physics? And how does it help me to say, how do I go from this
link |
incoherent collection of things happening in the universe to our definite perception and
link |
definite laws and so on, and sort of an applied version of consciousness. And I think the reason
link |
that sort of segues to a different kind of topic, but the reason that one of the things I'm
link |
particularly interested in is kind of what's the analog of consciousness in systems very different
link |
from brains. And so why does that matter? Well, you know, this whole description of this kind of
link |
well, actually, you know what, we haven't talked about why the universe exists. So let's let's
link |
get to why the universe exists. And then we then we can can talk about perhaps a little bit about
link |
what these models of physics kind of show you about other kinds of things like molecular computing
link |
and so on. Yes, that's good. Why does the universe exist? Okay, so we finally sort of more or less
link |
set the stage, we've got this idea of this really add of this object that is made from following all
link |
possible rules, the fact that it's sort of not just this incoherent mess, it's got all this
link |
entangled structure in it, and so on. Okay, so what is this really add? Well, it is the working out
link |
of all possible formal systems. So the sort of a question of why does the universe exist? It's
link |
core question, you kind of started with is, you've got two plus two equals four, you've got some other
link |
abstract results. But that's not actualized. It's just an abstract thing. And when we say we've
link |
got a model for the universe, okay, it's this rule, you run it, and it'll make the universe. But it's
link |
like, but, but, you know, where's it actually running? What, what, what is what is it actually
link |
doing? Right? What is is it actual? Or is it merely a formal description of something? Okay.
link |
So the thing to realize with this, with this, the thing about the rule yard is it's an inevitable,
link |
it is the entangled running of all possible rules. So you don't get to say it's not like you're saying,
link |
which rule yard are you picking? Because it's all possible formal rules. It's not like it's just,
link |
you know, well, actually, it's only footnote, the only footnote, it's an important footnote,
link |
is it's all possible computational rules, not hyper computational rules. That is,
link |
it's running all the rules that would be accessible to a Turing machine, but is not running all the
link |
rules that will be accessible to a thing that can solve problems in finite time that would take a
link |
Turing machine infinite time to solve. So you can even Alan Turing knew this that you could make
link |
oracles for Turing machines where you say, a Turing machine can't solve the whole thing problem
link |
for Turing machines, it can't know what will happen in any Turing machine after an infinite time
link |
in any finite time, but you could invent a box, just make a black box, you say, I'm going to sell
link |
you an oracle that will just tell you, you know, press this button, it'll tell you what the Turing
link |
machine will do after an infinite time, you can imagine such a box, you can't necessarily build
link |
one in the physical universe, but you can imagine such a box. And so we could say, well, in addition
link |
to, so in this Ruliad, we're imagining that there is a computational that at the end,
link |
it's, it's running rules that are computational. It doesn't have a bunch of
link |
oracle black boxes in it. You say, well, why not? Well, turns out if there are oracle black boxes,
link |
the Ruliad that is, you can make a sort of super Ruliad that contains those oracle black boxes,
link |
but it has a cosmological event horizon relative to the first one, they can't communicate.
link |
In other words, you can, you can end up with what you end up happening, what ends up happening is
link |
it's, it's, it's like in the physical universe, we, in this causal graph that represents the causal
link |
relationships of different things, you can have an event horizon, where there's, where the causal
link |
graph is disconnected, where the effect here, an event happening here does not affect an event
link |
happening here, because there's a disconnection in the causal graph. And that's what happens in an
link |
event horizon. And so what will happen between this kind of the ordinary Ruliad and the hyper Ruliad
link |
is there is an event horizon, and you, you know, we in our Ruliad will just never know that there
link |
is, that they're just separate things. They're not, they're not connected.
link |
Maybe I'm not understanding, but just because we can't observe it,
link |
why does that mean it doesn't exist? It might exist, but it does, it's not clear what it,
link |
it's so what, so to speak, whether it exists. You know, what we're trying to understand is why
link |
does our universe exist? We're not trying to ask the question what, you know, it's,
link |
let me say another thing, let me make a meta comment, okay, which is that, that I have not
link |
thought through this hyper Ruliad business properly. So I can't, the hyper Ruliad is referring to
link |
a Ruliad in which hyper computation is possible. That's correct. Okay. So like what the, that foot
link |
note, the footnote to the footnote is we're not sure why this is important. Yeah, that's right.
link |
So let's, let's ignore that. Okay. It's already abstract enough. Okay. So, so, okay. So the one
link |
question is, we have to say, if we're saying, why does the universe exist? One question is,
link |
why is it this universe and not another universe? Yeah. Okay. So the important point about this
link |
Ruliad idea is that it's in the Ruliad are all possible formal systems. So there's no choice
link |
being made. There's no, there's no like, oh, we picked this particular universe and not that one.
link |
That's the first thing. The second thing is the that we have to ask the question. So, so you say,
link |
why does two plus two equals four exist? That's not really a that is a thing that necessarily
link |
is that way, just on the basis of the meaning of the terms two and plus and equals and so on.
link |
Right. So the thing is that this, this Ruliad object is in a sense a necessary object. It is
link |
just the thing that is the consequence of working out the consequence of the formal definition of
link |
things. You don't, it is not a thing where you're saying, and this is picked as the particular
link |
thing. This is just something which necessarily is that thing because of the definition of what
link |
it means to have computation. So it's a Ruliad. It's a formal system. Yes.
link |
But does it exist? Ah, well, where are we in this whole thing? We are part of this Ruliad.
link |
And so our, so there is no sense to say, does two plus two equals four exist? Well, that's,
link |
that's in some sense, it necessarily exists. It's a necessary object. It's not a thing that
link |
where you can ask, you know, it's, it's usually in philosophy, there's a sort of distinction
link |
made between, you know, necessary truths, contingent truths, analytic propositions,
link |
synthetic propositions, there are a variety of different versions of this. They're things which
link |
are necessarily true, just based on the definition of terms. And there are things which happen to
link |
be true in our universe. But we're weird, we don't exist in Rulial space. We, that's one of the
link |
coordinates that define our existence, right? Well, okay, so, so yes, yes, but this Ruliad
link |
is the set of all possible Rulial coordinates. So what we're saying is it contains that. So what
link |
we're saying is we exist as, okay, so our perception of what's going on is we're at a particular
link |
place in this Ruliad. And we are concluding certain things about how the universe works
link |
based on that. But the question is, do we understand, you know, is there something where we say,
link |
so, so why does it work that way? Well, the answer is, I think it has to work that way,
link |
because this, there isn't, this Ruliad is a necessary object in the sense that it is a purely
link |
formal object, just like two plus two equals four. It's not an object that was made of something. It's
link |
an object that is just an expression of the necessary collection of formal relations that exist.
link |
And so then the issue is, can we, in our experience of that, is it, you know, can we have tables and
link |
chairs, so to speak, in that just by virtue of our experience of that necessary thing?
link |
And, you know, what people have generally thought, and also that I don't know of a lot of
link |
discussion of this, why does the universe exist question? It's been a very, you know,
link |
I've been surprised actually at how little, I mean, I think it's one of these things that's
link |
really kind of far out there. But the thing that that is, you know, the surprise here is that
link |
all possible formal rules, when you run them together, and that's the critical thing,
link |
when you run them together, they produce this kind of entangled structure that has a definite
link |
structure. It's not just, you know, a random arbitrary thing, it's a thing with definite
link |
structure. And that structure is the thing when we are embedded in that structure, when anything,
link |
you know, the an entity embedded in that structure perceives something, which is,
link |
then we can interpret as physics and things like this. So in other words, we don't have to ask the
link |
question, the why does it exist? It necessarily exists. I'm missing this part. Why does it
link |
necessarily exist? Okay, okay. So like you need to have it if you want to formalize the relation
link |
between entities, but why do you need to have relations? Okay, okay. So let's say you say,
link |
well, it's like, why does math have to exist? Okay, that's the question. Yeah, okay, fair question.
link |
Let's see. I think the thing to think about is the existence of mathematics is something where,
link |
given a definition of terms, what follows from that definition inevitably follows.
link |
So now you can say, why define any terms? But in a sense, the, well, that's okay. So the definition
link |
of terms, I mean, I think the way to think about this, let me see. So like, concrete terms?
link |
Well, that's not very concrete. I mean, they're just things like, you know,
link |
logical or right. But that's a thing. That's a powerful thing.
link |
Well, it's a, yes, okay. But it's a, the point is that it is not a thing about,
link |
people imagine there is, I don't know, the, an elephant or something or the,
link |
elephants are presumably not necessary objects. They happen to exist as a result of kind of
link |
biological evolution and whatever else. But the, the thing is that in some sense, that there is,
link |
it is a different kind of thing to say, does plus exist? The, it is not, it's not, not like an
link |
elephant. So a plus is, seems more fundamental, more basic than an elephant. Yes. But you can
link |
imagine a world without plus or anything like it. Like why do formal things that are discreet, that
link |
can be used to reason have to exist? Well, okay. So why, okay. So then the question is,
link |
but the whole point is computation, we can certainly imagine computation. That is,
link |
we can certainly say there is a formal system that we can construct abstractly in our minds
link |
that is computation. And that, that's the, and you know, we can, we can imagine it, right? Now,
link |
the question is, is it is that formal system, once we exist as observers embedded in that
link |
formal system, that's enough to have something which is like our universe. And so then the,
link |
then what you're kind of asking is, perhaps, is why, I mean, the point is we definitely
link |
can imagine it. There's nothing that says that we're not saying that there's, it's sort of inevitable
link |
that, that is a thing that we can imagine. We don't have to ask, does it exist? We're just,
link |
it is definitely something we can imagine. Now that's, then we have this thing that is
link |
a formally constructible thing that we can imagine. And now we have to ask the question,
link |
what, you know, given that formally constructible thing, what is, what consequences does that,
link |
if we were to perceive that formally, if we were embedded in that formally constructible thing,
link |
what would be perceived about the world? And we would say, we perceive that the world exists,
link |
because we are, we are seeing all of this mechanism of all these things happening. And,
link |
but that's something that is just a feature of, it's, it's, it's something where we are, see,
link |
another way of asking this that I'm trying to get at, I understand why it feels like this
link |
rulliad is necessary. But maybe it's just me being human, but it feels like then
link |
you should be able to, not us, but somehow step outside of the rulliad. Like what's
link |
outside the rulliad? Well, the rulliad is all formal systems. So there's nothing, because
link |
But that's what a human would say. I know that's what a human would say, because we're used to
link |
the idea that there are, there's, but the whole point is that by the time it's all possible,
link |
formal systems, it's, it's like, it is all things you can imagine. But no, all computations you can
link |
imagine. But like, we don't, well, so that could be a code. Okay. So, so that's a, that's a fair
link |
question. Is it possible to encode all, I mean, once we, is, is there something that isn't what
link |
we can represent formally? Right. That is, that is, there's something that, and that's, I think,
link |
related to the hyper rulliad footnote, so to speak, which I'm afraid that the, you know,
link |
one of the things sort of interesting about this is, you know, there has been some discussion of
link |
this in theology and things like that. But, which I don't necessarily understand all of.
link |
But the, the key sort of new input is this idea that all possible formal systems, it's like,
link |
you know, if you make a world, people say, well, you make a world with a particular, in a particular
link |
way, with particular rules, but no, you don't do that. You can make a world that deals with all
link |
possible rules, and then merely by virtue of living in a particular place in that world,
link |
so to speak, we have the perception we have of, of what the world is like. Now, I have to say,
link |
it's sort of interesting because I've, you know, I wrote this piece about this, and I, you know,
link |
this philosophy stuff is not super easy. And I've, as I'm, as I'm talking to you about it,
link |
and I actually haven't, you know, people have been interested in lots of different things we've
link |
been doing, but this, why does the universe exist has been, I would say, one of the, one of the
link |
ones that you would think people will be most interested in. But actually, I think they're
link |
just like, oh, that's just something complicated. So, so I haven't, I haven't explained it as,
link |
as much as I've explained a bunch of other things. And I have to say, I think I,
link |
I think I may be missing a couple of pieces of that argument that would be so, so it's kind of a
link |
like, well, you're, you're conscious being is computationally bounded. So you're missing,
link |
having written quite a few articles yourself, you, you're now missing some of the pieces.
link |
Yes, right. The limitation of being human. Right. One of the consequences of this,
link |
why the, why the universe exists thing and this kind of concept of Rulee ads and, and, you know,
link |
places in there representing our perception of the universe and so on, one of the weird
link |
consequences is, if the universe exists, mathematics must also exist. And that's a weird
link |
thing because mathematics, people have been very confused, including me, have been very confused
link |
about the, the, the question of, of kind of what, what is the foundation of mathematics,
link |
what is, what kind of a thing is mathematics is mathematics, something where we just write down
link |
axioms like Euclid did for geometry and we just build the structure and we could have written
link |
down different axioms and we'd have a different structure. Or is it something that has a more
link |
fundamental sort of truth to it? And I have to say it's one of these cases where I've, I've long
link |
believed that mathematics has a great deal of arbitraryness to it, that there are particular
link |
axioms that kind of got written down by the Babylonians. And, you know, that's what we've
link |
ended up with the mathematics that we have. And I have to say, actually, my, my wife has been telling
link |
me for 25 years, she was a mathematician, she's been telling me, you're wrong about the foundations
link |
of mathematics. And, and, you know, I'm like, no, no, no, I know what I'm talking about. And
link |
finally, she's, she's much more right than, than I've been. So it's, it's one of the.
link |
So I mean, her sense, in your sense, are we just, so this is to the question of metamath,
link |
mathematics, are we just kind of on a trajectory through
link |
through rural space, except in mathematics, through a trajectory of certain kind of
link |
I think that's partly the idea. So I think that the notion is this. So 100 years ago,
link |
a little bit more than 100 years ago, what people have been doing mathematics for ages,
link |
but then in the, in the late 1800s, people decided to try and formalize mathematics and say, you
link |
know, it is mathematics is, you know, we're going to break it down, we're going to make it like
link |
logic, we're going to make it out of, out of sort of fundamental primitives. And that was people
link |
like Frager and piano and Hilbert and so on. And they kind of got this idea of let's do kind of
link |
Euclid, but even better, let's just make everything just in terms of this sort of symbolic axioms,
link |
and then build up mathematics from that. And that, you know, they thought at the time,
link |
as soon as they get these symbolic axioms that they made the same mistake, the kind of computational
link |
irreducibility mistake, they thought as soon as we've written down the axioms, then it'll just
link |
we'll just have a machine, kind of a supermathematica, so to speak, that can just grind out all true
link |
theorems of mathematics. That got exploited by Goedl's theorem, which is basically the story
link |
of computational irreducibility. It's that even though you know those underlying rules,
link |
you can't deduce all the consequences in any finite way. And so, so that was, but now the question
link |
is, okay, so they broke mathematics down into these axioms. And they say now you build up from
link |
that. So what I'm increasingly coming to realize is, that's similar to saying, let's take a gas
link |
and break it down into molecules. There's gas laws that are the large scale structure and so on,
link |
that we humans are familiar with. And then there's the underlying molecular dynamics. And I think
link |
that the axiomatic level of mathematics, which we can access with automated theorem proving and
link |
proof assistance, and these kinds of things, that's the molecular dynamics of mathematics.
link |
And occasionally we see through to that molecular dynamics. We see undecidability, we see other
link |
things like this. One of the things I've always found very mysterious is that Goedl's theorem
link |
shows that there are sort of things which cannot be finitely proved in mathematics. There are proofs
link |
of arbitrary length, infinite length proofs that you might need. But in practical mathematics,
link |
mathematicians don't typically run into this. They just happily go along doing their mathematics.
link |
And I think what's actually happening is that what they're doing is they're looking at this,
link |
they are essentially observers in metamathematical space. And they are picking a reference frame
link |
in metamathematical space. And they are computationally bounded observers in metamathematical space,
link |
which is causing them to deduce that the laws of metamathematics and the laws of mathematics,
link |
like the laws of fluid mechanics, are much more understandable than this underlying molecular dynamics.
link |
And so what gets really bizarre is thinking about kind of the analogy between metamathematics,
link |
this idea of you exist in this kind of, in this sort of space of possible, in this kind of
link |
mathematical space where the individual kind of points in the mathematical space are statements
link |
in mathematics, and they're connected by proofs, where one statement, you know, you take a couple
link |
of different statements, you can use those to prove some other statement, and you've got this
link |
whole network of a proofs, that's the kind of causal network of mathematics of what can prove
link |
what and so on. And you can say at any moment in the history of a mathematician, of a single
link |
mathematical consciousness, you are in a single kind of slice of this kind of metamathematical
link |
space, you know a certain set of mathematical statements, you can then deduce with proofs,
link |
you can deduce other ones, and so on, you're kind of gradually moving through metamathematical space.
link |
And so it's kind of the view is that the reason that mathematicians perceive mathematics to have
link |
the sort of integrity and lack of kind of undecidability and so on that they do is because
link |
they like we as observers of the physical universe, we have these limitations associated with
link |
computational boundedness, single thread of time, consciousness limitations basically,
link |
that the same thing is true of mathematicians perceiving sort of metamathematical space.
link |
And so what's happening is that when you look at, if you look at one of these formalized
link |
mathematics systems, something like, you know, Pythagoras's theorem, it'll be, it'll take,
link |
oh, I don't know, what is it, maybe 10,000 individual little steps to prove Pythagoras's
link |
theorem. And one of the bizarre things that's sort of an empirical fact that I'm trying to
link |
understand a little bit better, if you look at different proof, if you look at different
link |
formalized mathematics systems, they actually have different axioms underneath that they can all
link |
prove Pythagoras's theorem. And so in other words, it's a little bit like what happens with gases,
link |
we can have air molecules, we can have water molecules, but they still have fluid dynamics,
link |
both of them have fluid dynamics. And so similarly, at the level that mathematics,
link |
that mathematicians care about mathematics, it's way above the molecular dynamics, so to speak.
link |
And they're all kinds of weird things, like for example, one thing I was realizing recently is
link |
that the quantum theory of mathematics, that's a very bizarre idea. But basically, when you prove,
link |
what is, you know, a proof is you've got one statement in mathematics, you go through other
link |
statements, you eventually get to a statement you're trying to prove, for example, that's a path,
link |
path in metamathematical space. And that's a single path, a single proof is a single path.
link |
But you can imagine, there are other proofs of the same results. They're a bundle of proofs.
link |
There's this whole set of possible proofs.
link |
You could think of as branching, similar to the quantum mechanics model that you were talking
link |
about. Exactly. And so then there's some invariance that you can formalize in the same way that you
link |
can for the quantum mechanical. Right. So the question is in proof space,
link |
you know, as you start thinking about multiple proofs, are there analogs of, for example,
link |
destructive interference of multiple proofs? So here's a bizarre idea. It's just a couple of
link |
days old, so not yet fully formed. But as you try and do that, when you have two different proofs,
link |
it's like two photons going in different directions, you have two proofs which at an
link |
intermediate stage are incompatible. And that's kind of like destructive interference.
link |
Is it possible for this to instruct the engineering of automated proof systems?
link |
Absolutely. I mean, it's a practical matter. I mean, this whole question, in fact, Jonathan
link |
Gorat has a nice heuristic for automated theorem provers that's based on our physics project
link |
that is looking for essentially using kind of using energy and in our models, energy is kind of
link |
level of activity in this hypergraph. And so there's sort of a heuristic for automated theorem
link |
proving about how do you pick which path to go down that is based on essentially physics.
link |
And I mean, the thing that gets interesting about this is, is the way that one can sort of have
link |
the interplay between like, for example, a black hole, what is a black hole in mathematics?
link |
So the answer is, what is black hole in physics? A black hole in physics is where,
link |
in the simplest form of black hole, time ends. That is all, you know, everything is crunched
link |
down to the spacetime singularity, and everything just ends up at that singularity. So in our models,
link |
and that's a little hard to understand in general relativity with continuous mathematics and what
link |
does singularity look like? In our models, it's something very pragmatic. It's just,
link |
you're applying these rules, time is moving forward. And then there comes a moment where the rules,
link |
no rules apply. So time stops. It's kind of like the universe dies. The, you know, the,
link |
the nothing happens in the universe anymore. Well, in mathematics, that's a decidable theory.
link |
That's a theory. So theories which have undecidability, which are things like arithmetic,
link |
set theory, all the serious models, theories in mathematics, they all have the feature that
link |
there are proofs of arbitrary long length. And something like Boolean algebra, which is a decidable
link |
theory, there are, you know, any question in Boolean algebra, you can just go crunch, crunch,
link |
crunch, and in a known number of steps, you can answer it. You know, satisfiability, you know,
link |
might be hard, but it's still a bounded number of steps to answer any satisfiability problem.
link |
And so that's the notion of a black hole in physics where time stops. That's the,
link |
that's analogous to in mathematics, where there aren't infinite length proofs, where when in
link |
physics, you know, you can wander around the universe forever, if you don't run into a black
link |
hole, if you run into a black hole and time stops, you're done. And it's the same thing in
link |
mathematics between decidable, decidable theories and undecidable theories. That's a,
link |
that's an example. And I think we're sort of the, the, the attempt to understand. So, so another
link |
question is kind of what is the, what is the generativity of, of metamathematics? What is the
link |
bulk theory of metamathematics? So in the literature of mathematics, there are about 3 million
link |
theorems that people have, have published. And those represent, it's kind of on this, it's like,
link |
like on the earth, we would be, you know, you know, we've put cities in particular places on the
link |
earth. But yet there is ultimately, you know, we know the earth is roughly spherical, and there's
link |
an underlying space. And we could just talk about, you know, the world of space in terms of where
link |
our cities happen to be, but there's actually an underlying space. And so the question is, what's
link |
that for metamathematics? And as we kind of explore what is, for example, for mathematics,
link |
which is always likes taking sort of abstract limits. So an obvious abstract limit for
link |
mathematics to take is the limit of the future of mathematics. That is, what is the limit of
link |
what will be, you know, the ultimate structure of mathematics. And one of the things that's
link |
an empirical observation about mathematics, that's quite interesting is that a lot of theories in
link |
one area of mathematics algebraic geometry or something might have, they play into another
link |
area of mathematics, that that same the same kind of a fundamental construct seem to occur
link |
in very different areas of mathematics. And that structurally captured a bit with category theory
link |
and things like that. But I think that there's probably an understanding of this metamathematical
link |
space that will explain why different areas of mathematics ultimately sort of map into the same
link |
thing. And I mean, you know, my little challenge to myself is what's time dilation in, in metamathematics?
link |
In other words, as you, as you basically as you move around in this mathematical space of possible
link |
statements, you know, what's how does that moving around? It's basically what's happening is that
link |
as you move around in the space of mathematical statements, it's like you're changing from
link |
algebra to geometry to whatever else. And you're trying to prove the same theorem. But as you try,
link |
if you keep on moving to these different places, it's slower to prove that theorem because you
link |
keep on having to translate what you're doing back to where you started from. And that's kind of the
link |
beginnings of the analog of time dilation in mathematics. Plus there's probably fractional
link |
dimensions in this space as well. Oh, this space is a very messy space. This space is much messier
link |
than physical space. I mean, even in, even in the models of physics, physical space is very tame
link |
compared to branchial space and rural space. I mean, the mathematical structure, you know,
link |
branchial space is probably more like Hilbert space, but it's a rather complicated Hilbert space.
link |
And rural space is more like this weird infinity groupoid story of growth and deacon. And, you
link |
know, I can explain that a little bit because in, you know, in, in metamathematical space,
link |
a, a path in metamathematical space is a, is a, a path between two statements is a way to get by
link |
proofs is to way to find a proof that goes from one statement to another. And so one of the things
link |
you can do, you can think about is you've got between statements, you've got proofs, and they
link |
are paths between statements. Okay. So now you can go to the next level and you can ask, what about
link |
a mapping from one proof to another? And so that's in, in category theory, that's kind of a higher
link |
category that notion of higher categories where you're, where you're mapping not just between,
link |
not just between objects, but you're mapping between the mappings between objects and so on.
link |
And so you can keep doing that. You keep saying higher order proofs. I want
link |
mappings between proofs, between proofs and so on. And that limiting structure. Oh, by the way,
link |
one thing that's very interesting is imagine in proof space, you've got these two proofs.
link |
And the question is, what is the topology of proof space? In other words, if you take these two
link |
paths, can you continuously deform them into each other? Or is there some big hole in the middle
link |
that prevents you from continuously deforming them one into the other? It's kind of like,
link |
you know, when you, when you think about some, I don't know, some puzzle, for example, you're
link |
moving pieces around on some puzzle, and you can think about the space of possible states of the
link |
puzzle. And you can make this graph that shows from one state of the puzzle to another state of
link |
the puzzle and so on. And sometimes you can easily get from one state to any other state,
link |
but sometimes there'll be a hole in that space. And there'll be, you know, you always have to
link |
go around the circuitous route to get from here to there. There won't be any direct way.
link |
And that's kind of a question of, of whether there's sort of an obstruction in the space.
link |
And so the question is in proof space, what is the, what are, you know, what does it mean if
link |
there's an obstruction in proof space? Yeah, I don't even know what an obstruction means in
link |
proof space, because for it to be an obstruction, it should be reachable some other way from some
link |
other place, right? So this is like an unreachable part of the graph.
link |
No, it's not just an unreachable part. It's a part where there are paths that go one way,
link |
there are paths that go the other way. And this question of homotopy and mathematics is this
link |
question, can you continuously deform, you know, from one path to another path? Or do you have to
link |
go in a jump, so to speak? So it's like, if you're going around a sphere, for example, if you're
link |
going around a, I don't know, a cylinder or something, you can wind around one way. And you
link |
can, there's no, the paths where you can, where you can easily deform one path into another,
link |
because it's just sort of sitting on the same side of the cylinder. But when you've got something
link |
that winds all the way around a cylinder, you can't continuously deform that down to a point,
link |
because it's stuck wrapped around. Well, my intuition about proof space is you should be
link |
able to deform it. I mean that, because then otherwise it doesn't even make sense. Because
link |
if the topology matters of the way you move about the space, then I don't even know what
link |
that means. Well, what it would mean is that you would have one way of doing a proof of something
link |
over here in algebra, and another way of doing a proof of something over here in geometry,
link |
and there would not be an intermediate way to map between those proofs.
link |
But how would that be possible if they started the same place and ended the same place?
link |
Well, it's the same thing as, you know, we've got points on a, you know, if we've got paths on
link |
a cylinder. I understand how it works in physical space, but it just doesn't, it feels like proof
link |
space shouldn't have that. Okay, I mean. I'm not sure. I don't know. We'll know very soon,
link |
because we get to do some experiments. This is the great thing about this stuff,
link |
is that in fact, you know, in the next few days, I hope to do a bunch of experiments on this.
link |
So you're playing like proofs in this kind of space? Yes. Yes. I mean, so, you know, this is toy,
link |
you know, theories, and, you know, we've got good, so this kind of segues to perhaps another thing,
link |
which is this whole idea of multi computation. So this, this is another kind of bigger idea that,
link |
so, okay, this has to do with how do you make models of things? And it's going to, it's, so
link |
I've sort of claimed that they've been sort of four epochs in the history of making models of
link |
things. And, and this multi computation thing is, is the fourth is a new epoch.
link |
What are the first three? The first one is, is back in antiquity, ancient Greek times, people were
link |
like, what's the universe made of? Oh, it's made of, you know, everything is water, Thales, you know,
link |
or everything is made of atoms. It's sort of what are things made of, or the, you know, there are
link |
these crystal spheres that represent where the planets are and so on. It's like a structural
link |
idea of how the universe is constructed. There's no real notion of dynamics. It's just what is the
link |
universe? How is the universe made? Then we get to the 1600s, and we get to the sort of revolution
link |
of mathematics being introduced into physics. And then we have this kind of idea of you write down
link |
some equation, the what happens in the universe is the solving of that equation, time enters,
link |
but it's usually just a parameter, we just can, you know, sort of slide it back and forth and say,
link |
here's where it is. Okay, then we come to this kind of computational idea that I kind of started
link |
really pushing in the early 1980s. As a result, you know, the things we were talking about before
link |
about complexity, that was my motivation. But the biggest story was the story of kind of computational
link |
models of things. And the big difference there from the mathematical models is in mathematical
link |
models, there's an equation, you solve it, you got kind of slide time to the place where you want it.
link |
In computational models, you give the rule, and then you just say, go run the rule. And time is not
link |
something you get to slide. Time is something where it just you run the rule, time goes in steps.
link |
And that's how you work out what how the system behaves, you don't time is not just a parameter.
link |
Time is something that is about the running of these of these rules. And so there's this computational
link |
irreducibility, you can't jump ahead in time. But there's still important thing is there's still
link |
one thread of time. It's still the case, you know, the cellular automaton state, then it has the next
link |
state and the next state and so on. The thing that is kind of we've sort of tipped off by quantum
link |
mechanics, in a sense, although it actually feeds back even into durability and things like that,
link |
that there are these multiple threads of time. And so in this multi computation paradigm, the
link |
kind of idea is, instead of there being the single thread of time, there are these kind of
link |
distributed asynchronous threads of time that are happening. And the thing that's sort of different
link |
there is, if you want to know what happened, if you say what happened in the system, in the case
link |
of the computational paradigm, you just say, well, after 1000 steps, we got this result. Right.
link |
But in the multi computational paradigm, after 1000 steps, not even clear what 1000 steps means,
link |
because you've got all these different threads of time. But there is no state. There's all these
link |
different possible, you know, there's all these different parts. And so the only way you can
link |
know what happened is to have some kind of observer who is saying here's how to parse the
link |
results of what was going on. Right. But that observer is embedded and they don't have a complete
link |
picture. So in the case of physics, that's right. Yes. And then in the, but that's, but so the idea
link |
is that in this multi computation setup, that it's this idea of these multiple threads of time,
link |
and models that are based on that. And this is similar to what people think about in non deterministic
link |
computation. So you have a Turing machine, usually it has a definite state, it follows another state,
link |
follows another state. But typically what people have done when they've thought about these kinds
link |
of things is they've said, well, there are all these possible paths and non deterministic Turing
link |
machine can follow all these possible paths. But we just want one of them, we just want the one
link |
that's the winner that factors the number or whatever else. And similarly, it's the same story
link |
in logic programming and so on. But we say we've got this goal, find us a path to that goal,
link |
I just want one path, then I'm happy. Or theorem proving same story, I just want one proof and
link |
then I'm happy. What's happening in multi computation in physics is we actually care about
link |
many paths. And well, there is a case for example, probabilistic programming is a version of
link |
multi computation in which you're looking at all the paths, you're just asking for probabilities of
link |
things. But in a sense in physics, we're taking different kinds of samplings. For example, in
link |
quantum mechanics, we're taking a different kind of sampling of all these multiple paths.
link |
But the thing that is notable is that when you are when you're an observer embedded in this thing,
link |
etc, etc, etc, with various other sort of footnotes and so on, it is inevitable that the thing that
link |
you parse out of this system looks like general activity and quantum mechanics. In other words,
link |
that just by the very structure of this multi computational setup, it inevitably is the case
link |
that you have certain emergent laws. Now, why is this perhaps not surprising? In thermodynamics
link |
and statistical mechanics, there are sort of inevitable emergent laws of sort of gas dynamics
link |
that are independent of the of the details of molecular dynamics, sort of the same kind of thing.
link |
But I think what happens is what's a sort of a funny thing that I just been understanding very
link |
recently is when when I kind of introduced this whole sort of computational paradigm complexity
link |
ish thing back in the 80s, it was kind of like a big downer, because it's like there's a lot of
link |
stuff you can't say about what systems will do. And then what I realized is and then you might say,
link |
now we've got multi computation, it's even worse, you know, it's isn't just one thread of time that
link |
we can't explain, it's all these threads of time, we can't explain anything. But the following thing
link |
happens, because there is all this irreducibility and any detailed thing you might want to answer,
link |
very hard to answer. But when you have an observer who has certain characteristics like computational
link |
boundedness, sequentiality of time and so on, that observer only samples certain aspects of this
link |
incredible complexity going on in this multi computational system. And that observer is sensitive
link |
only to some underlying core structure of this multi computational system. There is all this
link |
irreducible computation going on all these details. But to that kind of observer, what's
link |
important is only the core structure of multi computation, which means that observer observes
link |
comparatively simple laws. And I think it is inevitable that that observer observes laws which
link |
are mathematically structured like general relativity and quantum mechanics, which by the
link |
way, are the same law in our in our model of physics. So that's an explanation why there's
link |
simple laws that explain a lot for this observer. Potentially, yes. But what the place where this
link |
gets really interesting is there are all these fields of science where people have kind of gotten
link |
stuck where they say we'd really love to have a physics like theory of economics, we'd really
link |
love to have a physics like law and linguistics. You got to talk about molecular biology here.
link |
Okay. So where where where does multi computation come in for biology, economics is super
link |
interesting too, but biology. Okay, let's talk about that. So let's talk about chemistry for a
link |
second. Okay. So I mean, I have to say, you know, this is such a weird business for me because,
link |
you know, there are these kind of paradigmatic ideas and then the actual applications. And
link |
it's like I've always said, I know nothing about chemistry, I learned all the chemistry I know,
link |
you know, the night before some exam when I was 14 years old. But yeah, but I've actually learned
link |
a bunch more chemistry. And in more from language these days, we have really pretty nice symbolic
link |
representation of chemistry. And in understanding the design of that, I've actually I think learned
link |
a certain amount of chemistry. If you quizzed me on sort of basic high school chemistry,
link |
I would probably totally fail. But but but okay, so what is chemistry? I mean, chemistry is sort of
link |
a story of, you know, chemical reactions are like you've got this particular chemical that's
link |
represented as some graph of, you know, these are, these are this configuration of molecules
link |
with these bonds and so on. And a chemical reaction happens, you've got these sort of two
link |
graphs, they interact in some way, you've got another graph or multiple other graphs out. So
link |
that's kind of the, the sort of the, the abstract view of what's happening in chemistry. And so
link |
when you do a chemical synthesis, for example, you are given certain sort of these are possible
link |
reactions that can happen. And you're asked, can you piece together this a sequence of such reactions,
link |
a sequence of such sort of axiomatic reactions, usually called name reactions in chemistry,
link |
can you piece together a sequence of these reactions, so that you get out at the end,
link |
this great molecule you were trying to synthesize. And so that's a story very much like theorem
link |
proving. And people have done, actually, they started in the 1960s, looking at, at kind of the
link |
theorem proving approach to that, although it didn't really, it didn't, it didn't sort of done too early,
link |
I think. But anyway, so that's kind of the view is that that chemistry chemical reactions are
link |
this story of, of all these different sort of paths of possible things that go on. Okay, let's,
link |
let's go to an even lower level. Let's say, instead of asking about which species of molecules
link |
we're talking about, let's look at individual molecules. And let's say we're looking at individual
link |
molecules, and they are having chemical reactions. And we're building up this big graph of all these
link |
reactions that are happening. Okay, so, so then we've got this big graph. And by the way, that
link |
big graph is incredibly similar to these hypergraph rewriting things. In fact, in the underlying
link |
theory of multi computation, there, these things we call token event graphs, which are basically,
link |
you've broken your state into tokens, like in the case of a hypergraph, you've broken it into
link |
hyper edges. And each event is just consuming some number of tokens, and producing some number of
link |
tokens. But then you have to, there's a lot of work to be done on update rules.
link |
In terms of what they actually offer chemistry. Yeah, what they offer our observed chemistry.
link |
Yes, indeed. Yes, indeed. And we've been working on that actually, because we have this beautiful
link |
system in, in Wolfram language for representing chemistry symbolically. So we actually have,
link |
you know, this is a, this is an ongoing thing to actually figure out what they are for some
link |
practical cases. Does that require human injection or can it be automatically discovered, these
link |
update rules? Well, if we can do quantum chemistry better, we could probably discover them
link |
automatically. But I think in, in reality, right now, it's like, there are these particular
link |
reactions. And really, to understand what's going on, we're probably going to pick a particular
link |
subtype of chemistry. And just because, because let me explain where this is going, the place
link |
that here's, here's where this is going. So we've got this whole network of all these
link |
molecules, having all these reactions and so on. And this is some whole multi computational story,
link |
because each, each sort of chemical reaction event is its own separate event, we're saying
link |
they all happen asynchronously, we're not describing in what order they happen, you know,
link |
maybe that order is governed by some quantum mechanics thing, doesn't really matter,
link |
we're just saying they happen in some order. And then we ask, what is the, what's the, you know,
link |
how do we think about the system? Well, this thing is some kind of big multi computational
link |
system. The question is, what is the chemical observer? And one possible chemical observer is,
link |
all you care about is, did you make that particular drug molecule? You're just asking,
link |
you know, the, for the one path, another thing you might care about is, I want to know the
link |
concentration of each species, right? I want to know, you know, at every stage, I'm going to solve
link |
the differential equations that represent the concentrations. And I want to know what those
link |
all are. But there's more, because when, and it's kind of like, you're going below in statistical
link |
mechanics, there's kind of all these molecules bouncing around. And you might say, we're just
link |
going to ignore, we're just going to look at the aggregate densities of certain kinds of molecules,
link |
but you can look at a lower level, you can look at this whole graph of possible interactions.
link |
And so the kind of the idea would be, what, you know, is the only chemical observer,
link |
one who just cares about overall concentrations, or can there be a chemical observer who cares
link |
about this network of what happened? And so that the question then is, so let me give an analogy.
link |
So this is where I think this is potentially very relevant to molecular, molecular biology and
link |
molecular computing. When we think about a computation, usually we say, it's input, it's
link |
output, we, you know, or chemistry, we say, there's this input, we're going to make this molecule
link |
as the output. But what if what we actually encode, what if our computation, what if the
link |
thing we care about is some part of this dynamic network? What if it isn't just the input and
link |
the output that we care about? What if there's some dynamics of the network that we care about?
link |
Now, imagine you're a chemical observer, what is a chemical observer? Well, in molecular biology,
link |
there are all kinds of weird sorts of observers, there are membranes that exist that have, you
link |
know, different kinds of molecules that combine to them, things like this. It's not obvious that the,
link |
from a human scale, we just measure the concentration of something is the relevant story.
link |
We can imagine that, for example, when we look at this whole network of possible reactions,
link |
we can imagine, you know, at a physical level, we can imagine, well, what was the actual momentum
link |
direction of that, of that molecule? What was it, which we don't pay any attention to when we're
link |
just talking about chemical concentrations? What was the orientation of that molecule,
link |
these kinds of things? And so here's the place where I'm, I have a little suspicion, okay?
link |
So one of the questions in biology is what matters in biology? And that is, you know,
link |
we have all these chemical reactions, we have all these, all these molecular processes going on in,
link |
you know, in biological systems, what matters? And, you know, one of the things is to be able
link |
to tell what matters, well, so a big story of the what matters question was what happened in
link |
genetics in 1953 when DNA, when it was figured out how DNA worked. Because before that time,
link |
you know, genetics have been all these different effects and complicated things. And then it was
link |
realized, ah, there's something new, a molecule can store information, which wasn't obvious before
link |
that time, a single molecule can store information. So there's a place where there can be something
link |
important that's happening in molecular biology. And it's just in the sequence that's storing
link |
information in a molecule. So the possibility now is imagine this dynamic network, this, you know,
link |
causal graphs and multiway causal graphs and so on, that represent all of these different
link |
reactions between molecules. What if there is some aspect of that that is storing information
link |
that's relevant for molecular biology? In the dynamic aspect of that. Yes, that's right. So
link |
that it's similar to how the structure of a DNA molecule stores information, it could be the
link |
dynamics of the system, some stores information. And this kind of process might allow you to give
link |
predictions of what that would be. Well, yes, but also imagine that you're trying to do,
link |
for example, imagine you're trying to do molecular computation. Okay, you might think the way we're
link |
going to do molecular computation is, we're just going to run the thing, we're going to see what
link |
came out, we're going to see what molecule came out. This is saying that's not the only thing you
link |
can do. There is a different kind of chemical observer that you can imagine constructing,
link |
which is somehow sensitive to this dynamic network. Exactly how that works, how we make that
link |
measurement, I don't know, but a few ideas, but that that's what's important, so to speak. And
link |
that that means, and by the way, you can do the same thing, even for Turing machines, you can say
link |
if you have a multiway Turing machine, you can say, how do you compute with a multiway Turing
link |
machine? You can't say, well, we've got this input and this output, because the thing has all these
link |
threads of time, it's got lots of outputs. And so then you say, well, what does it even mean to be
link |
a universal multiway Turing machine? I don't fully know the answer to that. But it has an
link |
interesting idea, freak Turing out for sure. Because then the dynamics of the trajectory of
link |
the computation matters. Yes, yes. I mean, but the thing is that that so this is again a story of
link |
what's the observer, so to speak. And chemistry, what's what's the observer there? Now, to give
link |
an example of where that might matter, a very sort of present day example is in immunology,
link |
where, we have whatever it is, 10 billion different kinds of antibodies that are all
link |
these different shapes and so on, we have a trillion different kinds of T cell receptors
link |
that we can that we produce. And the traditional theory of immunology is this
link |
clonal selection theory, where we're constantly producing, randomly producing all these different
link |
antibodies. And as soon as one of those binds to an antigen, then that one gets amplified,
link |
and we produce more of that antibody and so on. Back in the 1960s, immunologist called Nils
link |
Yerner, who was the guy who invented molecular antibodies, various other things, kind of had
link |
this network theory of the immune system, where it would be like, well, we produce antibodies,
link |
but then we produce antibodies to the antibodies, anti antibodies, and we produce anti anti antibodies,
link |
and we get this whole dynamic network of interactions between different immune system
link |
cells. And that was that, that was kind of a qualitative theory at that time. And it's,
link |
I've been a little disappointed because I've been studying immunology a bit recently. And I knew
link |
something about this, like 35 years ago or something. And I knew, you know, I'd read a
link |
bunch of the books, and I talked to a bunch of the people and so on. And it was like an emerging
link |
theoretical immunology world. And then I look at the books now, and they're very thick, because
link |
they've got, you know, there's just a ton known about immunology, and, you know, all these different
link |
pathways, all these different details and so on. But the theoretical sections seem to have shrunk.
link |
And so it's, so the question is, what, you know, for example, immune memory, where is the,
link |
where does the immune memory reside? Is it actually some cell sitting in our bone marrow
link |
that is, you know, living for the whole of our lives that's going to spring into action as soon
link |
as we're showing the same antigen? Or is it something different from that? Is it something
link |
more dynamic? Is it something more like some network of interactions between these different
link |
kinds of immune system cells and so on? And it's known that there are plenty of interactions
link |
between T cells and, you know, there's plenty of dynamics. But what the consequence of that
link |
dynamics is is not clear. And to have a qualitative theory for that doesn't, doesn't seem to exist.
link |
In fact, I was just, just been trying to study this. So I'm quite incomplete in my study of
link |
these things. But I was a little bit taken aback because I've, I've been looking at these things.
link |
And it's like, and then they get to the end where they have the most advanced theory that they've
link |
got. And it turns out it's a cellular automaton theory. It's like, okay, well, at least I understand
link |
that theory. But, but, you know, I think that the possibility is that in, this is a place where,
link |
if you want to know, you know, explain roughly how the immune system works, it ends up being
link |
this dynamic network. And then the, the, you know, the immune consciousness, so to speak,
link |
the observer ends up being something that, you know, in the end, it's kind of like, does the human
link |
get sick or whatever. But it's a, it's something which is a complicated story that relates to this
link |
whole sort of dynamic network and so on. And I think that's another place where this kind of
link |
notion of, where, where I think multi computation has the possibility, see one of the things,
link |
okay, you can end up with something where, yes, there is a general relativity in there.
link |
There, but it turns out, but it may turn out that the observer who sees general relativity
link |
in the immune system is an observer that's irrelevant to what we care about, about the
link |
immune system. I mean, it could be, yes, there is some effect where, you know, there's some,
link |
you know, time dilation of T cells interacting with whatever, but it's like, that's an effect
link |
that's just irrelevant. And the thing we actually care about is things about, you know,
link |
what happens when you have a vaccine that goes into someplace in shapespace and, you know,
link |
how does that affect other places in shapespace and how does that spread? You know, what's the,
link |
what's the analog of the speed of light in shapespace, for example, that's an important issue.
link |
If you have one of these dynamic theories, it's like, you know, you're, you're poking to shapespace
link |
by having, you know, let's say, a vaccine or something that has a particular configuration
link |
in shapespace, how, how quickly as this dynamic network spreads out, how quickly do you get
link |
sort of other antibodies in different places in shapespace, things like that.
link |
When you say shapespace, you mean the shape of the molecules?
link |
And then, so this is like, it could be deeply connected to the protein and multi protein
link |
folding, all of that kind of stuff. So to be able to say something interesting about the
link |
dance of proteins, that then actually has an impact on helping develop drugs, for example,
link |
or has an impact on virology, immunology, helping.
link |
Well, I think that the big thing is, you know, when we think about molecular biology,
link |
the, you know, what, what is the qualitative way to think about it? You know, in other words,
link |
is it chemical reaction networks? Is it, you know, genetics, you know, DNA, big, you know,
link |
big news, it's kind of, there's a digital aspect to the whole thing.
link |
You know, what is the qualitative way to think about how things work in biology?
link |
You know, when we think about, I don't know, some phenomenon like aging or something,
link |
which is a big complicated phenomenon, which just seems to have all these different tentacles,
link |
is it really the case that, that can be thought about in some, you know, without DNA,
link |
when people were describing, you know, genetic phenomena that were, you know, dominant,
link |
recessive, this, that, and the other, it got very, very complicated. And then people realized,
link |
oh, it's just, you know, and what is a gene and so on and so on and so on.
link |
Then people realized it's just base pairs. And there's this digital representation. And so the
link |
question is, what is the overarching representation that we can now start to think about using a
link |
molecular biology? I don't know how this will work out. And this is again, one of these things
link |
where, and the place where that gets important is, you know, maybe molecular biology is doing
link |
molecular computing by using some dynamic process that is something where it is very happily saying,
link |
oh, I just got a result. It's in the dynamic structure of this network. Now I'm going to go
link |
and do some other thing based on that result, for example. But we're like, oh, I don't know what's
link |
going on. You know, it's just, we just measured them levels of these chemicals and we couldn't
link |
conclude anything. But it just we're looking at the wrong thing. And so that's kind of the potential
link |
there. And it's, I mean, these things are, I don't know, it's for me, it's like, I've not really,
link |
that was not a view. I mean, I've thought about molecular computing for ages and ages and ages.
link |
And I've always imagined that the big story is kind of the original promise of nanotechnology
link |
of like, can we make a molecular scale constructor that will just build the molecule in any shape?
link |
I don't think I'm now increasingly concluding, that's not the big point. The big point is something
link |
more dynamic. That will be an interesting endpoint for any of these things. But that's
link |
perhaps not the thing, you know, because the one example we have in molecular computing
link |
that's really working is us biological organisms. And, you know, maybe the thing that's important
link |
there is not this, you know, what chemicals do you make, so to speak, but more this kind of dynamic
link |
process dynamic process. And then you can have a good model like the hypo grafted to then
link |
explore what like simulated again, make predictions and if they
link |
I think just have a way to reason about biology. I mean, it's hard, you know, but first of all,
link |
biology doesn't have theories like physics, you know, physics is a much more successful sort of
link |
global theory kind of kind of area, you know, biology, what are the global theories of biology,
link |
pretty much Darwinian evolution, that's the only global theory of biology, you know, any other
link |
theory is just a, well, the kidneys work this way, this thing works this way and so on. There
link |
isn't, I suppose, another global theory is digital information in DNA. That's another sort of global
link |
fact about biology. But the difficult thing to do is to match something you have a model of in
link |
the hypo graft to the actual, like, how do you discover the theory? How do you discover the
link |
theory? Okay, you have something that looks nice and makes sense, but like, you have to match it
link |
to validation and experiment. Oh, sure, right. And that's tricky because you're walking around in
link |
the dark. Not entirely. I mean, so, you know, for example, and what we've been trying to think about
link |
is take actual chemical reactions. Okay. So, you know, one of my goals is, can I compute the primes
link |
with molecules? Okay, that's if I can do that, then I kind of maybe I can compute things. And,
link |
you know, there's this nice automated lab, these guys, these emerald cloud lab people have built
link |
with Wolfen language and so on. That's an actual physical lab. And you send it a piece of Wolfen
link |
language code and it goes and, you know, actually does physical experiments. And so one of my
link |
goals, because I'm not a test tube kind of guy, I'm more of a software kind of person, is can I
link |
make something where, you know, in this automated lab, we can actually get it so that there's some
link |
gel that we made. And, you know, the positions of the stripes are the primes. I love it. Yeah.
link |
I mean, that would be that will be an example of where and that will be with a particular,
link |
you know, framework for actually doing the molecular computing, you know, with particular
link |
kinds of molecules. And there's a lot of kind of ambient technological mess, so to speak, associated
link |
with Oh, is it carbon? Is it this? Is it that, you know, is it important that there's a bromine
link |
atom here, etc. etc. etc. This is all chemistry that I don't know much about. And, you know,
link |
that's that's a sort of, you know, unfortunately, that's down at the level, you know, I would like
link |
to be at the software level, not at the level of the transistors, so to speak. But in chemistry,
link |
you know, there's a certain amount we have to do, I think at the level of transistors before we get
link |
up to being able to do it, although, you know, automated labs certainly help in in setting that
link |
up. I talked to a guy named Charles Hoskinson. He mentioned that he's collaborating with you.
link |
He's an interesting guy. He sends me papers on speaking of automated theorem proving a lot.
link |
He's exceptionally well read on that area as well. So what's the nature of your collaboration
link |
with him? He's the creator of Cardano. What's the nature of the collaboration between Cardano
link |
and the whole space of blockchain and Wolfram, Wolfram Alpha, Wolfram Blockchain, all that kind
link |
of stuff. Well, okay, we're segueing to a slightly different world. But but so, although not completely
link |
I'm not completely unconnected. Right. The whole thing is somehow connected. I know. I mean,
link |
you know, the strange thing in my life is I've sort of alternated between doing basic science
link |
and doing technology about five times in my life so far. And the thing that's just crazy about it
link |
is, you know, every time I do one of these alternations, I think there's not going to be a
link |
way back to the other thing. And like I thought for this physics project, I thought, you know,
link |
we're doing fundamental theory of physics, maybe it'll have an application in 200 years.
link |
But now I've realized, actually, this multi computation idea is applicable here and now.
link |
And in fact, it's also giving us this way. I'll just mention one other thing. And then
link |
we're going to talk about blockchain. The question of actually that relates to several
link |
different things. But one of the things about, okay, so our Wolfram language, which is our attempt
link |
to kind of represent everything in the world computationally. And it's the thing I kind of
link |
started building 40 years ago, in the form of actual Wolfram language, 35 years ago. It's kind
link |
of this idea of can we can we express things about the world in computational terms. And,
link |
you know, we've come a long way in being able to do that. Wolfram Alpha is kind of the consumer
link |
version of that where you're just using natural languages as input. And it turns it into our
link |
symbolic language. And that's, you know, the symbolic language, Wolfram language is what
link |
people use and have been using for the last 33 years. Actually, Mathematica, which is its
link |
first instantiation, will be one third of a century old in October. And that it's kind of
link |
interesting. What do you mean one third of a century? Does it mean 33 or 30? What do we
link |
mean? 33 and a third. 33 and a third. So I've never heard of anyone celebrating that anniversary,
link |
but I like it. I know. A third of a century, though, it's like, you know, get many, many
link |
slices of a century that are interesting. But, you know, I think that the thing that's really
link |
striking about that is that means, you know, including the whole sort of technology stack
link |
I built around that's about 40 years old. And that means it's a significant fraction of the total
link |
age of the computer industry. And it's, I mean, I think it's cool that we can still run, you know,
link |
Mathematica version one programs today and so on. And we've sort of maintained compatibility.
link |
And we've been just building this big tower all those years of just more and more and more
link |
computational capabilities. It's sort of interesting, we just made this this picture
link |
of kind of the different kind of threads of computational content of, you know, mathematical
link |
content and, and, you know, all sorts of things with, you know, data and graphs and whatever
link |
else. And what you see in this picture is about the first 10 years, it's kind of like it's just
link |
a few threads. And then then about maybe 15, 20 years ago, it kind of explodes in this whole
link |
collection of different threads of all these different capabilities that are now part of
link |
orphan language and representing different things in the world. But the thing that was
link |
super lucky in some sense is it's all based on one idea. It's all based on the idea of symbolic
link |
expressions and transformation rules for symbolic expressions, which was kind of what I originally
link |
put into this SMP system back in 1979, that was a predecessor of the whole orphan language stack.
link |
So that idea was an idea that I got from sort of trying to understand mathematical logic and so
link |
on. It was my attempt to kind of make a general human comprehensible model of computation of
link |
the just everything is a symbolic expression. And all you do is transform symbolic expressions.
link |
And, you know, in, in retrospect, I was very lucky that I understood as little as I understood
link |
then, because had I understood more, I would have been completely freaked out about all the
link |
different ways that that kind of model can fail. Because what do you do when you have a symbolic
link |
expression, you make transformations for symbolic expressions? Well, for example, one question is
link |
there may be many transformations that could be made in a very multi computational kind of way.
link |
But what we're doing is picking, we're using the first transformation that applies. And we keep
link |
doing that until we reach a fixed point. And that's the result. And that's kind of a very,
link |
it's kind of a way of sort of sliding around the edge of multi computation. And back when I was
link |
working on SMP and things, I actually thought about these questions about about how, you know,
link |
how, what determines the this kind of evaluation path. So for example, you know, you work out
link |
Fibonacci, you know, Fibonacci is recursive thing, f of n is f of n minus one plus f of n minus two,
link |
and you get this whole tree of recursion, right. And there's the question of how do you evaluate
link |
that tree of recursion? Do you do it sort of depth first, where you go all the way down one side,
link |
you do it breadth first, where you're kind of collecting the terms together, where you know
link |
that you know, f of eight plus f of seven, f of seven plus f of six, you can collect the f of
link |
sevens and so on. These are, you know, I didn't realize that at the time, it's kind of funny,
link |
I was working on on gauge field theories back in 1979. And I was also working on the evaluation
link |
model in SMP, and they're the same problem. But it took me 40 more years to realize that.
link |
And this question about how you do this sort of evaluation front, that's a question of reference
link |
frames. It's a question of kind of the the story of, I mean, that that's, that is basically this
link |
question of, in what order is the universe evaluated? And that and so what you realize is
link |
there's this whole sort of world of different kinds of computation that you can do sort of
link |
multi computationally. And that's a, that's an interesting thing. It has a lot of implications
link |
for distributed computing and so on. It also has a potential implication for blockchain,
link |
which we haven't fully worked out, which is, and this is not what we're doing with Cardano, but
link |
this is a different thing. The, this is something where one of the questions is, when you have,
link |
in a sense, blockchain is a deeply sequentialized story of time, because in blockchain, there's
link |
just one copy of the ledger, and you're saying, this is what happened, you know, time has progressed
link |
in this way. And there are little things around the edges, as you try and reach consensus and so
link |
on. And, and, you know, actually, we just recently, we've had this little conference, we organized
link |
about the theory of distributed consensus, because I realized that a bunch of interesting things
link |
that some of our science can tell one about that. But that's a different, let's, let's not go down
link |
that, that part. Yeah, yeah. But distributed consensus that still has a sequential, there's
link |
like one. There's still sequentiality. So don't tell me you're thinking through like how to apply
link |
multi computation to blockchain. Yes. And so, so that becomes a story of, you know, instead of
link |
transactions all having to settle in one ledger, it's like a story of all these different ledgers,
link |
and they all have to have some ultimate consistency, which is what causal invariance would give one,
link |
but it can take a while. And the, it can take a while is kind of like quantum mechanics.
link |
So it's kind of what's happening is that these different paths of history that correspond to,
link |
you know, in one path of history, you got paid this amount in another path of history,
link |
you got paid this amount. In the end, the universe will always become consistent. Now,
link |
now the way it will, it works is, okay, it's a little bit more complicated than that. What happens
link |
is the way space is knitted together in our theory of physics is through all these events.
link |
And the, the, the idea is that the way that economic space is knitted together is,
link |
is there these autonomous events that essentially knit together economic space? So there are all
link |
these threads of transactions that are happening. And the question is, can they be made consistent?
link |
Are there, is there something forcing them to be sort of a consistent fabric of economic reality?
link |
And sort of what this has led me to is trying to realize how does economics fundamentally work?
link |
And, you know, what is economics? And, you know, what, what are the atoms of economics,
link |
so to speak? And so what I've kind of realized is that, that sort of the, perhaps I don't even
link |
know if this is right yet. There's sort of events in economics of transactions. There are states of
link |
agents that are kind of the atoms of economics. And then transactions are kind of agents,
link |
transact and some, transact in some way, and that's an event. And then the question is,
link |
how do you knit together sort of economic space from that? What is there an economic space? Well,
link |
all these transactions, there's a whole complicated collection of possible transactions. But one
link |
thing that's true about economics is we tend to have the notion of a definite value for things.
link |
We could imagine that, you know, you buy a cookie from somebody and they want to get a movie ticket.
link |
And there is some way that AI bots could make some path from the cookie to the movie ticket
link |
by all these different trans intermediate transactions. But in fact, we have an approximation
link |
to that, which is we say they each have a dollar value. And we have this kind of numeraire concept
link |
of there's just a way of kind of, of taking this whole complicated space of transactions
link |
and parsing it in something which is a kind of a simplified thing that is kind of like a parsing
link |
of physical space. And so my guess is that the yet again, I mean, it's crazy that all these things
link |
are so connected. This is another multi computation story, another story of where what's happening
link |
is that the economic consciousness, the economic observer is not going to deal with all of those
link |
are different microscopic transactions. They're just going to parse the whole thing by saying,
link |
there's this value, it's a number. And that's that's their understanding of their summary
link |
of this economic network. And there will be all kinds of things like they're all kinds of
link |
arbitrage opportunities, which are kind of like the quantum effects in this whole thing. And
link |
that's, you know, and places where there's where there's sort of different paths that can be followed
link |
and and so on. And there's so the question is, can one make a sort of global theory of economics?
link |
And then my test case is again, what is time dilation in economics? And and I know for,
link |
you know, if you imagine a very agricultural economics where people are growing lettuces and
link |
fields and things like this, and you ask questions about, well, if you're transporting
link |
lettuces to different places, you know, what is the value of the lettuces after you have to
link |
transport them versus if you're just sitting in one place and selling them, and you can kind of
link |
get a little bit of an analogy there. But I think there's a there's a better and more complete
link |
analogy. And that that's the question of is there a theory like general relativity, that is a global
link |
theory of economics? And is it about something we care about? It could be that there is a global
link |
theory, but it's about a feature of economic reality that isn't important to us. Now another
link |
part of the story is, can one use those ideas to make essentially a distributed blockchain,
link |
a distributed generalization of blockchain, kind of the quantum analog of money, so to speak,
link |
where where you have, for example, you can have uncertainty relations where you're saying, you
link |
know, well, if I if I insist on knowing my bank account right now, there'll be some uncertainty.
link |
If I'm prepared to wait a while, then it'll be much more certain. And so there's, you know,
link |
is there a way of using and so we've made a bunch of prototypes of this, which I'm not yet happy
link |
with, but I realized is to really understand these prototypes, I actually have to have a
link |
foundational theory of economics. And so that's kind of a, you know, it may be that we could
link |
deploy one of these prototypes as a practical system, but I think it's really going to be much
link |
better if we actually have an understanding of how this plugs into kind of economics.
link |
That means like a fundamental theory of transactions between entities. Well, that's what
link |
you mean by economics. Yes, I think so. But I mean, you know, how how there emerge sort of
link |
laws of economics, I don't even know. And I've been asking friends of mine who are who are
link |
economists and things, what is economics? You know, is it an axiomatic theory? Is it a theory
link |
that is a kind of a qualitative description theory? Is it, you know, what kind of a theory is it? Is
link |
it a theory? You know, what kind of thinking it's like, like in biology, in evolutionary biology,
link |
for example, there's a certain, there's a certain pattern of thinking that goes on in evolutionary
link |
biology, where if you're a, you know, a good evolutionary biologist, somebody says, that creature
link |
has a weird horn. And they'll say, well, that's because this and this and this and the selection
link |
of this kind and that kind. And that's the story. And it's not a mathematical story. It's a story
link |
of a different type of thinking about these things. By the way, evolutionary biology is yet
link |
another place where it looks like this multi computational idea can be applied. And that's
link |
where, where maybe speciation is related to things like event horizons. And there's a whole,
link |
whole other kind of world of that. But it seems like this kind of model can be applicable to so
link |
many aspects, like the different levels of understanding of our reality. So it can be the
link |
biology, the chemistry, at the physics level, the economics, and you could potentially say, the
link |
thing is, it's like, okay, sure, at all these levels in my rhyme, it might make sense as a
link |
model. The question is, can you make useful predictions at one of these levels?
link |
And that's, that's right. And that's, that's really a question of, you know, it's a weird
link |
situation because it's a situation where the model probably has definite consequences.
link |
The question is, are they consequences we care about? Yeah. And that's some, you know, and so,
link |
so in the case of, in the economic case, the, where, so, you know, the one, one thing is this,
link |
this idea of using kind of physics like notions to construct a kind of distributed analog block
link |
chain. Okay, the much more pragmatic thing is a different direction. And it has to do with
link |
this computational language that we built to describe the world that knows about, you know,
link |
different kinds of cookies and knows about different cities and knows about how to compute
link |
all these kinds of things. One of the things that is of interest is if you want to run the world,
link |
you need, you know, with, with, with contracts and laws and rules and so on. There are rules
link |
at a human level. And there are kind of things like, and so this, this gets one into the idea of
link |
computational contracts. You know, right now, when we write a contract, it's a piece of legalese,
link |
it's, you know, it's just written in English. And it's not something that's automatically
link |
analyzable, executable, whatever else, it's just English, you know, back in Gottfried Leibniz,
link |
back in, you know, 1680 or whatever, was like, I'm going to, you know, figure out how to use
link |
logic to decide legal cases and so on. And he had kind of this idea of, let's make a computational
link |
language for the human, for human law. Forget about modeling nature, forgot about natural laws.
link |
What about human law? Can we make kind of a computational representation of that?
link |
Well, I think finally we're close to being able to do that. And one of the projects that I hope
link |
to get to, as soon as the, there's a little bit of slowing down of some of this Cambrian explosion
link |
that's happening as a project I've been meaning to really do for a long time, which is what I'm
link |
calling a symbolic discourse language. It's just finishing the job of being able to represent
link |
everything like the conversation we're having in computational terms. And one of the use cases
link |
for that is computational contracts. Another use case is something like the Constitution that says
link |
what the AIs, what we want the AIs to do. But this is useful. So you're saying,
link |
so these are like, you're saying computational contracts, but the smart contracts, this is what's
link |
in the domain of cryptocurrencies known as smart contracts. And so the language you've developed,
link |
this symbolic or seek to further develop symbolic discourse language, enables you to
link |
write a contract. Write a contract that richly represents
link |
some aspect of the world. But so, I mean, smart contracts tend to be right now,
link |
mostly about things happening on the blockchain. And sometimes they have oracles. And in fact,
link |
our WolfMalpha API is the main thing people use to get information about the real world,
link |
so to speak, within smart contracts. So WolfMalpha, as it stands, is a really good oracle
link |
for whoever wants to use it. That's perhaps where the relationship with Cardano is.
link |
Yeah. Well, that's how we started getting involved with blockchains, as we realized people were
link |
using, you know, WolfMalpha as the oracle for smart contracts, so to speak. And so that got us
link |
interested in blockchains in general. And what was ended up happening is, WolfMalpha language is
link |
with its symbolic representation of things is really very good at representing
link |
things like blockchains. And so I think we now have, I mean, don't really know all the comparisons,
link |
but we now have a really nice environment within WolfMalpha language for dealing with the sort of,
link |
you know, for representing what happens in blockchains, for analyzing what happens in
link |
blockchains. We have a whole effort in blockchain analytics. And, you know, we've sort of published
link |
some samples of how that works. But it's, you know, because our technology stack, WolfMalpha language
link |
and Mathematica are very widely used in the quant finance world, there's a sort of immediate
link |
sort of co evolution there of sort of the quant finance kind of thing, and blockchain analytics.
link |
And that's some, so it's kind of the representation of blockchain in computational language.
link |
Then ultimately, it's kind of like, how do you run the world with code? That is, how do you write
link |
sort of all these things which are right now regulations and laws and contracts and things
link |
in computational language. And kind of the ultimate vision is that sort of something happens in the
link |
world. And then there's this giant domino effect of all these computational contracts that trigger
link |
based on the thing that happened. And there's a whole story to that. And of course, you know,
link |
I like to always pay attention to the latest things that are going on. And I really, I kind of like
link |
blockchain because it's a, it's a, it's another rethinking of kind of computation. It's kind of
link |
like, you know, cloud computing was a little bit of that of sort of persistent kind of
link |
computational resources and so on. And, you know, this multi computation is a big rethinking of
link |
kind of what it means to compute. Blockchain is another bit of rethinking of what it means to
link |
compute the idea that you lodge kind of these autonomous lumps of computation out there in
link |
the blockchain world. And one of the things that just sort of for fun, so to speak, as we've been
link |
doing a bit of stuff with NFTs, and we just did some NFTs on Cardano, and we'll be doing some more.
link |
And, you know, we did some cellular automaton NFTs on Cardano, like quite a bit. And, you know,
link |
one of the things I've realized about NFTs is that there's kind of this notion, and we're
link |
really working on this, you know, I like recording stuff, you know, one of the things that's come
link |
out of kind of my science, I suppose, is this history matters type story of, you know, it's
link |
not just the current stage, it's the history that matters. And I've kind of, I don't think this is,
link |
I should be realizing, maybe it's not coincidental that I'm sort of the human who's recorded more
link |
about themselves than anybody else. And then I end up with these science results that say history
link |
matters, which was not those things, I didn't think those were connected. But there are at least
link |
correlated, yes. Yeah, right. So, you know, this question about sort of recording what has happened
link |
and having sort of a permanent record of things, one of the things that's kind of interesting
link |
there is, you know, you put up a website and it's got a bunch of stuff on it. But, you know,
link |
you have to keep paying the hosting fees or the thing's going to go away. But one of the things
link |
about blockchain is quite interesting is if you put something on a blockchain and you pay,
link |
you know, your commission to get that thing, you know, put on, you know, mind put on the blockchain,
link |
then in a sense, everybody who comes after you is, you know, they are motivated to keep your
link |
thing alive, because that's what keeps the consistency of the blockchain. So in a sense,
link |
with sort of the NFT world, it's kind of like, if you want to have something permanent, well,
link |
at least for the life of the blockchain, but even if the blockchain goes out of circulation,
link |
so to speak, there's going to be enough value in that whole collection of transactions
link |
that people are going to archive the thing. But that means that, you know, pay once,
link |
and you're kind of, you're lodged in the blockchain forever. And so we've been kind of playing around
link |
with the sort of a hobby thing of mine of thinking about sort of the NFTs and how you,
link |
and sort of the consumer idea of kind of the, it's the anti, you know, it's the opposite of the
link |
Snapchat view of the world. There's a permanence to it that's heavily incentivized. And thereby,
link |
you can have a permanence of history. Right. And that's kind of the, now, you know, so that's one
link |
of the things we've been doing with Cardano. And it's kind of fun. I think that, I mean,
link |
this whole question about, you know, you mentioned automated theorem proving and blockchains and
link |
so on. And as I've thought about this kind of physics inspired distributed blockchain,
link |
obviously, they're the sort of the proof that it works, that there are no double spends,
link |
there's no whatever else. That proof becomes a very formal kind of almost a matter of physics,
link |
so to speak. And, you know, it's been, it's been an interesting thing for the,
link |
for the practical blockchains to do kind of actual automated theorem proving. And I don't
link |
think anybody's really managed it in an interesting case yet. It's a thing that people,
link |
you know, aspire to, but I think it's a challenging thing. Because basically the point is one of the,
link |
one of the things about proving correctness of something is, well, you know, people say,
link |
I've got this program, and I'm going to prove it's correct. And it's like, what does that mean?
link |
You have to say what correct means. I mean, it's, it's kind of like, then you have to have
link |
another language. And people are very confused back in past decades of, you know, oh, we're
link |
going to prove the correctness by representing the program in another language, which we also
link |
don't know whether it's correct. And, you know, often by correctness, we just mean it can't crash
link |
or it can't scribble on memory. But, but the thing is that there's this complicated tradeoff.
link |
Because as soon as there's, as soon as you're really using computation, you have computational
link |
irreducibility, you have undecidability, if you want to use computation seriously, you have to
link |
kind of let go of the idea that you're going to be able to box it in and say, we're going to have
link |
just this happen and not anything else. I mean, this is a, this is an old fact. I mean, Goedl's
link |
theorem tries to say, you know, piano arithmetic, the axioms of arithmetic, can you box in the integers
link |
and say these axioms give just the integers and nothing but the integers? Goedl's theorem showed
link |
that wasn't the case. There's a, you know, you can have all these wild, weird things that are
link |
obey the piano axioms, but aren't integers. And there's this kind of infinite hierarchy
link |
of additional axioms you would have to add. And it's kind of the same thing. You don't get to,
link |
you know, if you want to say, I want to know what happens, you're boxing yourself in, and there's
link |
a limit to what can happen, so to speak. So it's a, it's a complicated tradeoff. And it's a,
link |
it's a, it's a big tradeoff for AI, so to speak. It's kind of like, do you want to let computation
link |
actually do what it can do? Or do you want to say, no, it's very, very boxed in to the point
link |
where we can understand every step. And that's a, that's kind of a thing that, that, that becomes
link |
difficult to do. But that's some, I mean, in general, I would say one of the things that's
link |
kind of complicated in my sort of life and the whole sort of story of computational language
link |
and all this technology and science and so on. I mean, I kind of, in the flow of one's life,
link |
it's sort of interesting to see how these things play out. Because I, you know, I've kind of concluded
link |
that I'm in the business of making kind of artifacts from the future, which means, you know,
link |
there are things that I've done, I don't know, this physics project, I don't know whether anybody
link |
would have gotten to it for 50 years. You know, the fact that mathematics is a third of a century
link |
old. And I know that a bunch of the core ideas are not well absorbed. I mean, that is, people
link |
finally got this idea that I thought was a triviality of notebooks, that was 25 years.
link |
And, you know, some of these core ideas about symbolic computation and so on,
link |
are not, are not absorbed. I mean, people, people use them every day in Wolfram language,
link |
and you know, do all kinds of cool things with them. But if you say, what is the fundamental
link |
intellectual point here, it's, it's not well absorbed. And it's, it's something where you
link |
kind of realize that you're, you're sort of building things. And I kind of made this, this
link |
thing about, you know, we're building artifacts from the future, so to speak. And I mentioned that
link |
it's our, we have a conference every, it's coming up actually in a couple of weeks, our annual
link |
technology conference, where we talk about all the, all the things we're doing. And, you know,
link |
so I was talking about it last year, about, you know, we're making artifacts from the future.
link |
And I was kind of like, I had some, some version of that that was kind of a dark and frustrated
link |
thing of like, you know, I'm building things which nobody's going to care about until long
link |
after I'm dead, so to speak. But, but, but then I realized, you know, people were sort of telling
link |
me afterwards, you know, that's exactly how, you know, we're using Wolfram language in some
link |
particular setting in, you know, some computational X field or some organization or whatever. And
link |
it's like people are saying, Oh, you know, what did you manage to do? You know, well, we know
link |
that in principle, it will be possible to do that, but we didn't know that was possible now.
link |
And it's kind of like that's the, that's sort of the business we're in. And in a sense,
link |
with some of these ideas in science, you know, I feel a little bit the same way that there are
link |
some of these things where, you know, some, some things like, for example, this whole idea, well,
link |
so, so to, to relate to another sort of piece of history and the future, one of, you know,
link |
I mentioned, we mentioned at the beginning kind of complexity as this thing that I was interested
link |
in back 40 years ago and so on, where does complexity come from? Well, I think we kind of
link |
nailed that. The answer is in the computational universe, even simple programs make it. And
link |
that's kind of the secret the nature has that allows you to make it. So, so that's kind of the
link |
that that's that part. But the bigger picture there was this idea of this kind of computational
link |
paradigm, the idea that you could go beyond mathematical equations, which have been sort of
link |
the primary modeling medium for 300 years. And so it was like, look, it is inexorably the case
link |
that people will use programs, rather than just equations. And, you know, I was saying that in
link |
the 1980s. And people were, you know, I published my big book, New Kind of Science, that'll be 20
link |
years ago, next year. So in 2002, and people are saying, Oh, no, this can't possibly be true. You
link |
know, we know, for 300 years, we've been doing all this stuff, right? To be fair, I now realize
link |
on a little bit more analysis of what people actually said, in pretty much every field other
link |
than physics, people said, Oh, these are new models, that's pretty interesting. In physics,
link |
people were like, we've got our physics models, we're very happy with them.
link |
Yeah, in physics, there's more resistance because of the attachment and the power of the equations,
link |
right? The idea that programs might be the right way to approach, right, this field was,
link |
there's some resistance and like you're saying, it takes time for somebody who likes the idea of
link |
time dilation and all these applications, I thought you would understand this.
link |
Yeah, right. But you know, and computational irreducibility,
link |
yes, exactly. But I mean, it is really interesting that just 20 years, a span of 20 years,
link |
it's gone from, you know, pitchforks and horror to, yeah, we get it. And, you know, it's helped
link |
that we've, you know, in our current effort in fundamental physics, we've gotten a lot further,
link |
and we've managed to put a lot of puzzle pieces together, that makes sense. But the thing that
link |
I've been thinking about recently is this field of complexity. So I've kind of was a sort of a
link |
field builder back in the 1980s, I was kind of like, okay, you know, can we, you know, I'd
link |
understood this point that there was this sort of fundamental phenomenon of complexity, it showed up
link |
in lots of places. And I was like, this is an interesting sort of field of science. And I was
link |
recently was reminded I was at this, the very first sort of get together of what became the
link |
Santa Fe Institute. And I was like, in fact, there's even an audio recording of me sort of
link |
saying, people have been talking about, oh, what should this, you know, outfit do? And I was saying,
link |
well, there is this thing that I've been thinking about, it's this kind of idea of complexity.
link |
Nice. And it's kind of like, and that's, that's what that ended up.
link |
And you planted the seed of complexity to Santa Fe. That's beautiful. It's a beautiful vision.
link |
But I mean, so that, but what's happened then, is this idea of complexity and, you know,
link |
can, you know, and I started the first research center at University of Illinois for doing that
link |
in the first journal, complex systems and so on. And, and it's kind of an interesting thing in my
link |
life, at least that it's kind of like, you plant the seed, you have this idea, it's a kind of a
link |
science idea, you have this idea of sort of focusing on the phenomenon of complexity. The
link |
deeper idea was this computational paradigm. But the nominal idea is this kind of idea of
link |
complexity. Okay, then you roll time forward 30 years or whatever, 35 years, whatever it is.
link |
And you say, what happened? Okay, well, now there are 1000 complexity institutes around the world.
link |
I think, more or less, we've been trying to count them. And, you know, there are 40 complexity
link |
journals, I think. And so it's kind of like, what actually happened in this field? Right.
link |
And I look at a lot of what happened. And I'm like, you know, I have to admit,
link |
there's some eye rolling, so to speak. Because it's kind of like, like, what is what's what's
link |
actually going on? Well, what people definitely got was this idea of computational models.
link |
And then they got but they thought one of the one of the kind of cognitive mistakes, I think,
link |
is they say, we've got a computational model. And it's, and we're looking at a system that's
link |
complex. And our computational model gives complexity by golly, that must mean it's right.
link |
And unfortunately, because complexity is a generic phenomenon and computational irreducibility
link |
is a generic phenomenon that actually tells you nothing. And so then the question is, well,
link |
what can you do? You know, there's a lot of things that have been sort of done under this banner
link |
of complexity. And I think it's been very successful in providing sort of an interdisciplinary
link |
way of connecting different fields together, which is powerful in itself. Right. I mean,
link |
that's a very useful economics. And yeah, it is. It's a good organizing principle. But in the end,
link |
a lot of that is around the sort of computational paradigm, computational modeling. That's the
link |
raw material that powers that kind of that kind of correspondence, I think. But the question is
link |
sort of what is the, you know, I was just thinking recently, you know, we've been, I mean, the other
link |
we've been, we've been for years, people have told me, you should start some Wolfram Institute
link |
that does basic science. You know, all I have is a company that that builds software and we,
link |
you know, we have a little piece that does basic science as kind of a hobby. People are saying,
link |
you should start this Wolfram Institute thing. And, and I've been, you know, because I've known
link |
about lots of institutes, and I've seen kind of that flow of money and, and kind of, you know,
link |
what happens in different situations and so on. So I've been kind of reluctant, but, but I've,
link |
I've, I have realized that, you know, what we've done with our company over the last 35 years,
link |
you know, we built a very good machine for doing R&D and, you know, innovating and creating things.
link |
And I just applied that machine to the physics project. That's how we did the physics project
link |
in a fairly short amount of time with a, you know, efficient machine with, you know, various people
link |
involved and so on. And so, you know, it works for basic science. And it's like, we can do more of
link |
this. And so now... In biology and chemistry, so it's become an institute. Yes. Well, it needs to
link |
become an institute. An official institute. Right. But the thing that, so I was thinking about,
link |
okay, so what do we do with complexity? You know, what, what, there are all these people who've,
link |
you know, what, what should happen to that field? And what I realized is, there's kind of this area
link |
of foundations of complexity that's about these questions about simple programs, what they do,
link |
that's far away from a bunch of the detailed applications that people... Oh, it's not far away.
link |
It's the, it's the under, you know, the bedrock underneath those applications. And so I realized
link |
recently, this is my recent kind of little innovation of a sort, a post that I'll do very soon,
link |
the, about kind of, you know, the foundations of complexity, what really are they? I think
link |
they're really two ideas, two conceptual ideas that I hadn't really enunciated, I think, before.
link |
One is what I call metamodeling. The other is rulliology. So what is metamodeling? So metamodeling
link |
is, you've got this complicated model, and it's a model of, you know, hedgehogs interacting with
link |
this, interacting with that. And the question is, what's really underneath that? What is it?
link |
You know, is it a Turing machine? Is it a cellular automaton? You know,
link |
what is the underlying stuff underneath that model? And so there's this kind of meta science
link |
question of, given these models, what is the core model? And I realized, I mean, to me,
link |
that's sort of an obvious question. But then I realized, I've been doing language design for 40
link |
years. And language design is exactly that question, you know, underneath all of this
link |
detailed stuff people do, what are the underlying primitives? And that's a question people haven't
link |
tended to ask about models. They say, well, we've got this nice model for this and that and the
link |
other. What's really underneath it? And what, you know, because once you have the thing that's
link |
underneath it, well, for example, this multi computation idea is an ultimate metamodeling
link |
idea, because it's saying underneath all these fields is one kind of paradigmatic structure.
link |
And, you know, you can, you can imagine the same kind of thing, much more sort of,
link |
much sort of shallower levels in different kinds of modeling. So the first activity is this kind
link |
of metamodeling, the kind of the models about models, so to speak, you know, what is the,
link |
what's, you know, drilling down into models? That's one thing. The other thing is this,
link |
this thing that I think we're going to call Ruleology, which is kind of the, okay, you've got
link |
these simple rules, you've got cellular automata, you've got Turing machines, you've got substitution
link |
systems, you've got register machines, you've got all these different things. What do they actually
link |
do in the wild? And this is an area that I've spent a lot of time, you know, working on and
link |
it's a lot of stuff in my new kind of science book is about this, you know, this new book I wrote
link |
about combinators is, is full of stuff like this. And, and this journal complex systems has lots of
link |
papers about these kinds of things. But, but there isn't really a home for people who do
link |
Ruleology or what I'm not. As you call the basic science of rules. Yes. Yes. Right. So it's, it's
link |
like, you've got some, what is it? Is it mathematics? No, it isn't really like mathematics. In fact,
link |
from my now understanding of mathematics, I understand that it's the molecular dynamics level.
link |
It's not the level that mathematicians have traditionally cared about. It's not computer
link |
science, because computer science is about writing programs that do things, you know,
link |
that were for a purpose, not programs in the wild, so to speak. It's not physics, it doesn't have
link |
anything to do with, you know, it may be underneath some physics, but it's not physics as such.
link |
So it just hasn't had a home. And if you look at, you know, but what's great about it is,
link |
it's a surviving field, so to speak. It's, it's something where, you know, one of the things I,
link |
I find sort of inspiring about mathematics, for example, is you look at mathematics that was done,
link |
you know, in ancient Greece, ancient, you know, Babylon, Egypt and so on, it's still here today.
link |
You know, you find an icosahedron that somebody made in ancient Egypt, you look at it, oh,
link |
that's a very modern thing. It's an icosahedron, you know, it's a timeless kind of, kind of activity.
link |
And this idea of studying simple rules and what they do, it's a timeless activity. And I can see
link |
that over the last 40 years or so, as, you know, even with cellular automata, it's kind of like,
link |
you know, you can sort of catalog what, what are the different cellular automata used for.
link |
And, you know, like the simplest rules, like, like one, you might even know this one, rule 184.
link |
It's rule 184 is a minimal model for road traffic flow. And, you know, it's also a
link |
minimal model for various other things. But it's kind of fun that you can literally say,
link |
you know, rule 90 is a minimal model for this and this and this. Rule four is a minimal model for
link |
this. And it's kind of remarkable that you can just buy in this raw level of this kind of study
link |
of rules. They then branch, they're the raw material that you can use to make models of
link |
different things. So it's a, it's a very pure basic science. But it's one that, you know,
link |
people have explored it, but they've been kind of a little bit in the wilderness. And I think,
link |
you know, one of the things that I would like to do finally is, is, you know, I always thought that
link |
sort of this notion of pure and chaos, pure and chaos being the acronym for my book, New Kind of
link |
Science, was, was something that people should be doing. And, you know, we tried to figure out
link |
what's the right institutional structure to do this stuff. You know, we, we dealt with a bunch
link |
of universities. Oh, you know, can we do this here? Well, what department would be in it? Well,
link |
it isn't in a department. It's, it's its own new kind of thing. That's why, that's why the book was
link |
called the New Kind of Science. It's kind of the, the, because that's an increasingly good description
link |
of what it is, so to speak. We're actually, we were thinking about kind of the rheological society,
link |
because we're realizing that it's kind of, it's, it's some, you know, there's a, there's a, it's
link |
very, it's very interesting. I mean, I've never really done something like this before, because
link |
there's this whole group of researchers who are, who've been doing things that are really,
link |
in some cases, very elegant, very surviving, very solid, you know, here's this thing that
link |
happens in this very abstract system. But it's like, it's like, what is that part of, you know, it's,
link |
it doesn't have a home. And I think that's something I, you know, I kind of fault myself for not
link |
having been more, you know, when complexity was developing in the 80s, I didn't understand the,
link |
the, the danger of applications. That is, it's really cool that you can apply this to economics,
link |
and you can apply it to evolutionary biology, and this and that and the other. But what happens
link |
with applications is everything gets sucked into the applications. And the pure stuff,
link |
it's like the pure mathematics, there isn't any pure mathematics, so to speak. It's all just
link |
applications of mathematics. And I, I failed to kind of make sure that this kind of pure area was,
link |
was kind of maintained and, and, and developed. And I think now, you know, one of the things I,
link |
I want to try to do, and, and, you know, it's a funny thing because I'm used to, look, I've been a,
link |
a tech CEO for more than half my life now. So, you know, this is what I know how to do. And, you
link |
know, I can, I can make stuff happen, and get projects to happen, even as it turns out, basic
link |
science projects, in that kind of setting, and how that translates into kind of, you know,
link |
there are a lot of people working on, for example, our physics project sort of distributed through
link |
the academic world, and that's working just great. But the question is, you know, can we have a sort
link |
of accelerator mechanism that makes use of kind of what we've learned in, in sort of R&D innovation?
link |
And, you know, but on the other hand, it's a funny thing because, you know, in a company,
link |
in the end, the thing is, you know, it's a company, it makes products that sell things,
link |
sells things to people. In, you know, when you're doing basic research, one of the challenges is
link |
there isn't that same kind of, of sort of mechanism. And so it's, it's, it's, you know, how do you
link |
drive the thing in a, in a kind of, in a lead kind of way, so that it really can, can make
link |
forward progress rather than, you know, what can often happen in, you know, in academic settings
link |
where it's like, well, there are all these flowers blooming, but it's not clear that there, you know,
link |
that it's, you have to have a central mission and a drive, just like you do with the company
link |
that's delivering a big overarching product. And that's, that's, but the challenges, you know,
link |
when you have a, the, the, the economics of the world are such that, you know, when you're delivering
link |
a product and people say, wow, that's useful, we'll buy it. And then that kind of feeds back
link |
in, okay, then you can, then you can pay the people who build it to eat, you know, so they can eat
link |
and so on. And with basic science, the payoff is very much less visible. And, and, you know,
link |
with the physics project, as I say, the big surprise has been that, I mean, you know,
link |
for example, well, the big surprise with the physics project is that it's looks like it has
link |
near term applications. And I was like, I'm guessing this is 200 years away. It's, I was kind of using
link |
the analogy of, of, you know, Newton, starting a satellite launch company, which would have been
link |
kind of wrong time. And, you know, but, but it turns out that's not the case. But, but we can't
link |
guarantee that. And if you say, we're signing up to do basic research, basic rheology, let's say.
link |
And, you know, and we can't, we don't know the horizon, you know, it's an unknown horizon. It's
link |
kind of like an undecidable kind of proposition of when is this proof going to end, so to speak?
link |
When is it going to be something that, that they get supplied? Well, I hope this is, this becomes a
link |
vibrant new field of rheology. I love it. Like I told you many, many times, it's one of the most
link |
amazing ideas that has been brought to this world. So I hope you get a bunch of people to explore
link |
this world. Thank you once again for spending a really valuable time with me today. Fun stuff. Thank
link |
you. Thanks for listening to this conversation with Stephen Wolfram. To support this podcast,
link |
please check out our sponsors in the description. And now let me leave you with some words from
link |
Richard Feynman. Nature uses only the longest threads to weave her patterns. So each small piece
link |
of her fabric reveals the organization of the entire tapestry. Thank you for listening and hope
link |
to see you next time.