Dr. Stephen Wolfram (5:05)
Gosh, I've spent my life kind of alternating between doing technology and doing basic science. It's pretty cool because you do technology for a while, you build a bunch of tools that let you do more things in basic science. You do basic science for a while, gives you ideas that let you build more technology. I've iterated that about five times so far in my life. I've been building this kind of tower of things in technology and things in science that's pretty tall by now. And I feel like we can see a long way from that tower. So what can we see? I think the thing that's been really interesting is the foundations of a whole bunch of fields have turned out to be somewhat related in their kind of conceptual Setup and places where we can make progress. So one big one is physics. Trying to understand sort of what the universe is made of, what's underneath space and time and so on. That's one big area. Trying to understand kind of the foundations of mathematics turns out to be closely related to, in ways that I certainly didn't expect. A bunch of things recently about the foundations of biology and things like why does biological evolution work and what actually is living matter? What kind of, you know, what strange thing is this kind of arrangement of molecules that is a living system. And so there are a whole bunch of applications. And also turned out that a lot of questions that have been kind of long time philosophical questions that seemed like they couldn't be addressed by science, we can start to talk about in scientific ways, things like what free will is and why it exists and what's going on with that. Even questions like why does the universe exist? These are questions that I had not expected we'd have anything to say about from science. And turns out we do. Now, in terms of sort of the kind of stack of ideas, kind of a lot of what I've done starts from one thing that I discovered back in the 1980s that was really surprising to me. And I think it's sort of the thing that broke my previous intuition. And here's what it is. If you say, imagine that you set up some rules for how something operates. And it might be a little program that you write for a computer. You just tell the computer, just keep running those rules, see what happens. You might think if you know the rules by which something operates, that that would kind of tell you what the thing is going to do. And at some level, if you follow the rules, you just run one step, the next step, the next step. You can see what happens after a billion steps or whatever else. The question is, can you kind of jump ahead, can you, with your mind and your mathematics or whatever else, can you kind of be smarter than this little program and just say, I know what you're going to do in a billion steps. Here's what it is. I can look at how you're set up or the rule that you're set up with, and then I can just jump ahead and say, this is what's going to happen in a billion steps. A lot of exact science in the past is really based on the idea that yes, you can predict what's going to happen in systems. And the thing that I kind of discovered is that, no, that actually doesn't work when you are kind of out in the computational universe of possible little rules, possible little programs. A large number of those kinds of programs have this thing that I call computational irreducibility. You kind of can't tell what's going to happen except by running each step and seeing what happens. So that's kind of a thing that at one level is sort of a limitation on what you can know in science. You can know the fundamental rules, but if you say, okay, I know the rules by which, you know, some little piece of a brain works, okay, so how does. What is the whole brain going to do? The answer is there's a limitation to what you can say about that. So that was kind of. That was kind of an early discovery. Then there are questions like, so one of the things that's really surprising from that is very simple rules can do very complicated things. So then you start asking, well, okay, the biggest thing we know about is the universe. So could it be the case that the universe just operates according to some very simple rule, and everything we see, all the complexity that we see in the world, is just a consequence of kind of irreducibly running that rule? And so that's the thing I thought about for many, many years. And about five years ago, kind of made what was at first kind of a rather technical breakthrough and then became a much bigger story. And it's kind of the question of what is the universe actually made of? And I think we have a pretty good idea at this point. And it's kind of exciting because a lot of progress was made in physics about 100 years ago with relativity and quantum mechanics and so on, and things kind of got to a point where sort of rather incremental progress. Back when I was a kid, I was involved in that incremental progress and I think contributed a bit to it. I happened to work on those things at a time when a lot was just becoming possible. But now I think we're able to actually make some progress again. So the question starts off. You start off with, well, what's the universe made of? So, you know, we usually think that sort of there's. Space is a sort of fundamental thing in the universe. And we have space, we have time. And the question is, is space made of something? So it's been sort of a question about things in the universe ever since antiquity, which is, Is the universe made of discrete stuff, or is it made of continuous kinds of things? Are there atoms that are sort of discrete elements that things are made of? Or does everything kind of flow like a fluid, like water or something like this people wondered about that for a long time. It wasn't really resolved until the end of the 19th century that matter is made of discrete stuff. Matter is made of atoms and molecules and so on. They became key. You could think about light as being made of discrete photons and so on. Early part of the 20th century, most people believed that space would also turn out to be discrete. But people couldn't make that work sort of in the technical mathematics of what was going on then. What we figured out a few years ago is yes, you can actually make that work. And you can think of space and sort of everything in it as being this thing that is made of just these sort of atoms of space, these just points and then relations between points. So it's as if there's sort of a giant friend network of the atoms of space. And that's kind of everything that exists in the universe. There's this giant kind of network of points that is the stuff that the universe is made of. And then you can ask, well, what does that thing do? Well, you say, well, every time there's a little piece of it that has a particular form, it will get transformed to a piece that has some other form. That sort of computational step applied many, many times is the thing that leads to the progress of time in the universe. Now that's the big deal is that you can go from the kind of more precise version of that description to, to say, okay, this is what the universe will seem like to an observer like us on a large scale. And the way it will seem turns out to follow what we know about the structure of space, time and the way gravity works and things like this. So it's a very exciting to me a non trivial thing that you can go from this very simple underlying description to kind of the things that we, as rather large entities relative to the atoms of space, perceive is going on. I mean, it's the same kind of story. If you think about something like a glass of water or something, you might say it's a continuous thing, it just flows as water flows. But actually we know at a microscopic scale there's a bunch of molecules bouncing around in that water. It's just to us at the scale we're at, it seems like it's just this continuous thing. And it seems like that's the same story with space. We may or may not be lucky in the sense that in the beginning of the 20th century turned out molecules are big enough that with the equipment one had at the time, one could tell they exist to know that There are atoms of space. We may or may not be living in the right century to have the equipment that we need to be able to actually say, yes, we can absolutely tell that there are discrete atoms of space. But so that. That's. That's. That's. So the kinds of things that.