5min chapter

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Currents 100: Sara Walker and Lee Cronin on Time as an Object

The Jim Rutt Show

CHAPTER

The Importance of Time Theory

Jim Racho: If you guys are right, you actually kill Einstein's block universe. I mean, your theory and his theory are incompatible. He says the error of time is nothing but the effect of a few weird, rare asymmetries in particle decomposition. Maybe a universe will look like that, he adds.

00:00
Speaker 2
Maybe a
Speaker 3
universe will look like that. And I actually, and we'll get to this later, but if you guys are right, you actually kill Einstein's block universe. I mean, your theory and his theory are incompatible, not a bad day's work, take down old Albert on time. Well, yeah,
Speaker 1
there's before we kill Einstein, I think Einstein did something very, very interesting in terms of understanding giving us relativity. Okay, relativity still works in a world in which time is irreversible. And so, and I think the problem is that when he got to the clock universe and extension that that is kind of like, it's a hard, it's a hard thing to basically make thing something testable on. And the thing which I've always said about my intuition on time is it's an argument we can have, but we have to somehow make it testable. So we only kill the block universe if we come up with a reasonable, I mean, it doesn't have to be testable to the billionth degree, but it has to come up with a new mechanism and understanding that makes sense of the world in a new way. And would be great if it became predictive as well as explanatory.
Speaker 3
Yep. And you guys are pointing in that direction, you know, that's why I was so excited when I read the article, right to go. This is not yet another minor tweak to science, right? This is a big one. And that's what we like to talk about here on the Jim Racho. So before we move on, I'm going to get a little bit of reading on theories of time again, refreshing my memory. And some of the historical models of why why time seems to have this arrow that it seems to be irreversible. You know, the famous example from like high school physics is an egg dropped on the floor and splattering. You say, well, you can't run that movie backward and have it make any sense. So that's essentially the thermodynamic arrow of time, Boltzmann, Boltzmann equations and all that, that disorder increases. And somehow the increase of disorder itself is the arrow of time. And that sounds like it's something but not quite right. And then there's the idea of the cosmological arrow of time that again, this take Big Bang literally that the world started as a singularity. I'm not quite there, but something very, very small, at least, and something explosion happened and everything's been moving out from that. And so, you know, moving from the state of a point to the state of Big itself provides an arrow of time, which is then closely related. And I say that your guys fall into this family, the causal arrow of time that, you know, somebody described history as one damn thing after another. And you could say after another implies time. And if causality is real and causality is sequenced, then one could say at a minimum that the sequence of causal relationships has something to do with the apparent error of time. And then of course, us physics fanboys love our K on decay as a particle physics explanation. There are people take that seriously. And the error of time is nothing but the effect of a few weird, rare asymmetries in particle decomposition. I find that unlikely, but it's a theory. And then the last one, it's kind of a fuzzy theory. And that is that somehow, and it's related to the causal arrow arrow theory, I would argue, that quantum decoherence, the fact that quantum states collapse the classical states all the time itself is a driver of what appears to us to be the era of time. And I would suggest that you have to combine that with the causal error family of of arrows of time to come up with something useful. So anyways, is that a, is that a fair way to categorize the space of arrow of time theories?
Speaker 2
I think that is, I just want to make a point clear about the causal arrow of time that I find really interesting is that your reversibility needs to be an emergent property in the sense, I mean, emergent, whatever that word means, but in the sense that in order for something to be caused, you have to have a mechanism that can cause it in one direction. So it could be the case that your reversibility only occurs if you have something that can cause the same process to happen both forwards and backwards. And those might be implemented in different machines. So this is one of the reasons that in biology, where all your objects are evolved, that you may not have mechanisms for reversing the process, because they would have to evolve too. So you'd actually have to instantiate in a physical object something that could have the information or pattern to reverse a particular process that evolved. And that's sort of a non trivial feature, I think in physics, reversibility is easy because none of those processes require memory to ever form. But if you want to have a reversible process in more complex systems, you actually have to have the memory for the forward process and for the reverse process.

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