Seth Lloyd - Events and the Nature of Time

Seth we're both at this fqxi conference in Banff this beautiful area about the physics of events the importance of events and understanding what physics is and one of the topics that we're looking at is the nature of time and how events can help us understand what time really is how does that work how can events help us understand what time is well an event is something that unfolds in time like a clock ticking or an electron moving from here to there or a bit flipping in a computer or you know just our thoughts moving on and our conversation progressing um now time is a mysterious thing and we don't understand it well I mean heraclitus said that time is like a river like this beautiful River here and the water flowing and then time ever moving onward and um but what makes us feel and perceive the time is going um so uh the first answer is I don't know Dom is every question is the same yeah um but but there are uh different arrows of time there's a perceptual era of time where we don't know something and then we know something that we didn't know this is about getting information um there's a conversation talking back and forth interacting where where you tell me some information I get the information I tell you something you get the information we both completely failed to comprehend each other but that's cool that's normal um then there's a second law of Thermodynamics which says that entropy which is a form of information tends to increase which is disorder yeah it's a kind of disorder this is related to the idea of an event in quantum mechanics because in quantum mechanics an event can be uh thought of as something where you know electron moves from here to there or there's an interaction with the environment the interaction kind of randomizes what happens D coheres what happens as it said and and then this adds a little bit of Randomness into the system and it makes something happen you know suddenly an electron was here and there at the same time now it's either here or there that can be considered an event in quantum mechanics so so to understand time though there I I I perceive there are two different ways of thinking about it one is that the events as you say sequence occur in time the other way to think about it uh is that there is no time there's just an event and then another event and we call that time but it's not really time uh so is this and people get really angry you know in an intellectual way about both which position their their phone is time real in other words events occurring in time or is time an illusion or something artificial or emergent or coming out of other things that that that and then that and that the real reality are our events time is a derivative of events now is this uh a a distinction without a difference or is there something fundamental here I can answer that question in one word Robert and the word is whatever [Laughter] if it's whatever that's important but most people say it's not whatever most people say either side is is a fundamental what is it because time is such a fundamental part of the of existence so um uh the other position which from ancient Greek philosopher paracelso said time is laid out all for once nothing is fixed nothing happens and this of course is the position in Einstein's theory of general relativity where space and time are a manifold and all the events are laid out in time once and for all and you know they're just sitting there and then of course we experience things as changing because we're moving through time but it's all just all these events are just like you're moving through space that you're moving through this space time yeah four-dimensional block universe so to speak yeah and that's a very deterministic it's uh you know somebody dies they're they're still there in part of this system as Einstein supposedly said to uh the wife of a friend who died I understand that but it was not a big consolation frankly I mean oh God Einstein God shut up but I I I I always wonder is this just literary metaphor or is there a real ontological a deep meaning and deep structure in terms of the positions about time well look the heracliten and paracelsian points of view they sound very different but they are equivalent to each other in terms of our experience one being flow and one being it's all it's all there all the time yeah that's right that's right that they're you know they describe the same situation in different Fashions they're equivalent to each other from an empirical fashion so so that's why I said is that right you can't get you can't do measurements you can't do experiments that can distinguish between the two is that what you do sure I mean yeah absolutely like like let's suppose we think of of a heracliten view of of general relativity where we think of time flowing like a river from the past to the Future and then we are riding along this River experiencing what's going on and we compare that to the Einstein picture is it the whole history of the river is just laid out and we're traveling through it as as traveling through we experience it the same way so my feeling is whatever it doesn't matter it's like you can pick this picture the Einstein picture the paracelsian picture you can pick the haircutson picture and their equivalent in terms of our experience okay that's that I think I I would agree with that but I think you're missing a a deep fundamental reality I mean I want to know what's what's below it I mean it's whatever for uh whether in terms of experiments or our personal lives or going to the movie certainly agree but I want to know what deep reality is all about you mean I I can't know that's why you are talking to you well Robert that's why you are the host of a show called Closer to truth because you want to find this deep underline coming to you in this beautiful setting I could just be looking at the environment instead of talking I want to learn what if I were to tell you there is no deeper underlying reality that if we have two equivalent pictures of what's going on they're both equally real would that be upsetting to you well it would be if that were the truth it doesn't matter whether it's upsetting or not at a mental level I'd be happy that if that's reality that there's this uncertainty I I would then still ask is the uncertainty in in an epistemological and knowledge sense or is it an uncertainty at a deep reality ontological sense look if if um from the perspective of physics if I have two pictures you know two theories physical theories one in which time flows and one in which time is static but they give the same empirical content yeah you cannot distinguish between them they're both equally good well why do your colleagues fight so much about this well because I don't know they need something to do in the afternoon they got to justify their jobs I don't know um no I think actually people are you know some people like the kind of river flowing being sitting by this River and so beautiful and flowing but I happen to be a hair Clayton at the moment I'm gonna I'm going to go with the flow here um some people like the everything is just laid out in a static uh position for all time like the Einstein picture um you know some people just have a feeling that they prefer this rather than other that's just a preference you know the the two are equivalent to each other so from the the perspective of science they're the same

Channel: Closer To Truth

Views: 9,495

Keywords: closer to truth, robert lawrence kuhn, Seth Lloyd, Nature of Time

Id: 7XAql2SlAgU

Length: 7min 48sec (468 seconds)

Published: Thu Jan 19 2023