Time is really not just like space. Time is a very different phenomenon from space. The fact that relativity emerges as this connection between space and time is something that is kind of an emergent thing. It's not something that is intrinsic to the nature of space or the nature of time. Time, I think, can be thought of as the sort of inexorable progress of computation in the universe.

Steven, the thing that always comes up, when we talk about these theory subjects, time, life, and consciousness, nobody can define it. Nobody ever gives me a satisfactory definition that those 3, you know, people in those fields can agree upon. And therefore, I think it's kind of bunk. But today, we're gonna delve into how we can actually understand what time is intrinsically, as you say, but also apply it to our field, my field, cosmic microwave background. Its temperature and polarization. So, Steven, how are you doing today?

I'm doing well. Thank you.

The first thing I wanna ask you about is, is is what time is to you versus what it is to the general listening layperson. We have the brightest audience in the known multiverse, but the question is we all sort of it's it's kinda like the old supreme court definition of pornography, you know, you know it when you see it. But I'd like to connect it both with your physics project and with my science array project. That's for you to actually do what you do uniquely well, which is to make things that are very complex, utterly understandable, but preserve the fascination. So, Stephen Time. Yes. Your recent article starts with this deceptively simple, but really profound question. Time is a central feature of human experiment, But what actually is

it?

What are you suggesting in this to me revolutionary new monograph?

What is time? People people will say well we can say it's now, it's sometime in the future. We think of time as like a position. We say, you know, we have a clock and we're looking at a smartphone or whatever and it reads a certain time. And it feels a lot like we're just saying where we are in some thing where we can be moving through it. The thing that's a bit odd about time immediately is unlike space, where most of the time we're just in one place in space, so we think of ourselves as being in one place in space and we kind of have to decide to move to another place in space, time doesn't work that way. Time inexorably moves forward for us. So that's that's the first kind of thing which kind of distinguishes it from space. I think one of the things that sort of happened in 20th century physics as a result of some of the technicality of relativity is people got the idea space and time are the same kind of thing and that was a kind of actually Einstein I don't think really thought that.

I think Minkowski, mathematician who kind of came to sort of clean up the mathematics of special relativity by 19 0 9 or so was saying well we noticed that we have these expressions for proper time for for space time science. It's x squared minus t squared and that reminds him of these things in mathematics quadratic forms and so well, let's just think of time as being a coordinate just like space and that's kind of where the whole notion of time is just like space came from. I think that time is really not just like space. Time is a very different phenomenon from space and the fact that relativity emerges as this connection between space and time is something that is kind of an emergent thing. It's not something that is intrinsic to the nature of space or the nature of time. The place to start in understanding time and it's in a sense very unsurprising once you kind of see what what's going on is time I think can be thought of as the sort of inexorable progress of computation in the universe. So what does that mean? Well, let's say we just define rules for some system. Might be a system of black and white squares, might be some set of graphs that connect different different nodes together, but it's just some rule that says whenever you see a configuration that looks like this, replace it by a configuration that looks like that.