Time & Mind: Was Einstein Wrong About Time?

I'm delighted, I hope, to introduce the next speaker if he's here. So, has Lee arrived? Lee, welcome. I know you've had to get up early to give this talk, so we're most appreciative. And I'll make a few brief remarks in introducing you. Lee is the professor of theoretical physics at the Perimeter Institute for Theoretical Physics, an adjunct professor of physics at the University of Waterloo, and a member of the graduate faculty of the philosophy department at the University of Toronto. His 2006

book, The Trouble with Physics, criticised string theory as a viable scientific theory. He has made contributions to quantum gravity theory, in particular the approach known as loop quantum gravity. He advocates that the two primary approaches to quantum gravity, loop quantum gravity and string theory, can be reconciled as different aspects of the same underlying theory. He also advocates an alternative view of space and time that he calls temporal naturalism. His research interests also includ

e cosmology, elementary particle theory, foundations of quantum mechanics and theoretical biology. And I should also add that he's written several books on time, and I well recall your book Time Reborn, Lee, which had a big effect on me. So I'm really delighted to be able to introduce you to give this, your talk, which is entitled The Role of Qualia in Temporal Naturalism. Over to you, Lee. The title of course has a pun in it, because temporal naturalism has a future. And I'll start in a moment

with a comment to George's talk. This is work done with three people, particularly Clelia Verde, Roberto Mangabiera Unger and Marina Cortes, and they collaborated at different phases in this. If I told this as a historical narrative, by the way, am I here? Do you guys hear me well? Yes or no? Sorry, your sound is slightly muted, Lee. Yes, well I'm slightly muted. Let's see if I can speak more loudly. Is that better? Yep. Well, carry on. We can hear you anyway now. Okay, good, good, good, good,

good. So let me start by saying this talk represents a long evolution in my thought of more than 15 or 20 years, where I went from a rather conventional theorist, as some will remember, who believes that time emerged from the Wheeler-DeWitt equation, such nonsense or incorrect views, to a view now which I think is more centrally about the nature of time, the evolution of time, than any view that's represented here. In particular, we're going to argue, we have argued in a number of papers, that t

here is no future, because the future is uncertain. The quantum wave function exists with something that we put together to allow us to predict the future. There is, however, in a proposition to George, also no past. The past is, happened, and that the wave functions have all collapsed when you're talking about the past. The past, therefore, is just described by the definite classical values, whatever we're seeing, and what's left is the present, which is where all the dynamics of the universe l

ives. Okay, and that's what I'm going to argue. Let's see. A very important part of my research program is that I try to solve all the key problems in physics simultaneously. I don't think it makes sense to just solve the fundamental problems in quantum mechanics leave cosmology out of this. The universe definitely exists, it's all that exists, and we want a theory which describes all that exists. Therefore, any problem about quantum mechanics is a problem about cosmology. Our solution to it is

a proposal for how to describe a space-time in terms of events that happen as they happen, which we call energetic causal sets. We also very much, in this work, we depend on the idea that the laws evolve, and I'll argue why the laws must evolve, and indeed the difference between phenomena which are perceived, which we would say are in the mind, are something in the nature of qualia. The distinction between those events and events that are not perceived is for us, is the event needed or a part of

the evolution of the laws in time. So, we tightly bind the questions of what are the laws, which how the laws evolve, and that has to do very much for me with consciousness or mind, but I don't have a detailed theory of that. So, we're going to be interested in a class, start of with hidden variable theories, or relational hidden variable theories. We're going to end up with a class of periods called energetic causal sets, and we'll see that that leads us to a kind of restricted kind of psychis

m. Okay. Now, our kind of elevator pitch is that the universe is nothing but a large number of partial views of itself, making up a briefly present presence. These events create and react with each other as they explore the different ways that a universe might be. So we very much have indefiniteness in the future, definiteness in the past, and the present is where the distinction is made. So this is an outline of what I'm going to talk about. To start with, we're going to start with the basic ph

ysics, which for me is something we'll call energetic causal set. In this view of the world, time is fundamental, energy is fundamental, momentum is fundamental, nothing else. We're going to have to describe from that how space emerges, space-time emerges, matter emerges, quantum emerges, etc. This is a kind of prelude. We propose that the world is based on one distinction and one distinction only, the distinction between what is definite and what is indefinite. A quantum measurement is one of a

number of different processes that take an indefinite state to one that becomes definite. The memory of that change is an event, and the cause of that event is the other events that are also present at the time. So we want to say that the world now consists of the just-made past of the events that are happening just now. So a quantum measurement takes an indefinite state to one that becomes definite. This view, by the way, is not original with us. It came, as we understand it, from Heisenberg.

Heisenberg talked about the fact that the quantum wave function should only be applied to describe the present because only the… I'm sorry, to describe the future because only the future is indefinite. The past is done if the measurements have happened or not happened, and everything from there on is definite but plays no causal role in what follows and is therefore non-existent. So this is how we divide up our cosmology. We call it the dynamics of difference. So in our cosmology, what is real a

nd what is fundamental? Present events are real, which are moments of definition and their views. What is emergent and their views? Let me back up. If you look around you and take a snap of your finger, that there is a network of events that come up from the past, which really means, if you think about it, they're coming from the future, coinciding at the event, which we call the event, the fundamental event. So an event, every event is… Well, the events all together make the causal sets, which

are propagating new information to you. So we think of something like the past light cone. If you look back instantaneously, what you see, it is a sphere around you of information coming to you from the past, and we call that your past. And we call the set of information coming to you from the past, your view. And that's all we claim is real at any moment, the views of the events that make up that moment. So what is emergent? What's emergent is everything else. Space is emergent for us, space-ti

me, because it's an aspect of space, fields are emergent, particles are emergent, and so forth. How do we formulate the laws of physics? Well, there's no space, so we can't use the normal tools like differential equations, so forth. There's no space, there's no derivatives, there's no functions of space. So how can we invent and present and describe the laws of motion? We do it in terms of differences between views of nearby events. And what is nearby? Nearby is have almost the same view. If I a

nd you stand next to each other, we look out, what we see is a series of views almost the same. And that we could explain by saying, well, we saw almost the same view, because we're standing near to each other looking out the same way. But we want to say, let's turn that around. Let's define seeing almost the same view as what we mean by being nearby, and define a metric based on comparisons of nearby views. And that's what we do in detail. So what emerges from that? What emerges as our show or

point of place where we show how space, space-time, fields, and particles, obeying classical space-time laws, emerge from this description. And of course, they emerge as a description of the nearby past. Okay? So, and this view of variety is a measure of the, if we consider here's a view, and here's an event, there's this view, here's another event, here's this view, we measure the difference between them. That is kind of a measure of the complexity of the world. In fact, Julian Barber and I inv

ented mathematically this notion of variety as a measure of complexity of views. And we're going to take over that work. Okay? So this probably doesn't need much discussion here, but if you're going to label me, I'm a realist. Within realism, I'm a temporal Leibnizian realist. And what that means is that I believe that the universe as we describe it is causally closed to the future, to the past. The future is weakly causally composed because it's, we don't see the whole of the future and we don'

t see the whole of the past. So these are all, the way Leibniz might have spoken about it, partial views of the near past connected to each other and sort of sewn together. So there is nothing outside this view making of the universe. There is nothing, there is nothing outside the universe, there's nothing that influences it from the outside. And anything that influences the future is also part of the universe. So we're going to be associating measurements and consciousness with ultimately cosmo

logical states. And I'll show you how we'll do that. Okay. Let's go. So this is a summary of what we've been saying. Again, let me start this from a different direction. This cosmology has nothing that's everlastingly present. The, what you might call the fundamental beables, which are the, for you might be the events, are really the events in process, events being always a change from something indefinite to something definite. Time is a process which continually brings together present states

of, that is events, to cause, to the cause of future events. So we have a law of nature might be, find the events that are most different, the three most different events in your combination of past of those three events. Maximize variety within that, that is the ones which are the triple which is most different from the others. And ask those three most different ones to reduce a fourth one, which becomes the invention of the next stage of the universe. So there are causal processes, which are t

he creation of a new event from existing events, existing that is at the same moment of time you exist. So the view of an event is what is known as its causal path. So we're just summarizing that and everything else is emergence. Okay, any questions at this point? I think when we know how much time we've got. Okay. Well, this is again a summary but with some more detail. So, if you would describe in detail cosmology generated like that, which we, especially Marina Cortes, described many of them

you pick a number, and that number will be when the set that is moving construction of this causal set, but with the energy and momentum playing key roles, because the interactions say find the three most something or two most something or whatever, and when you found those, evolve by one step by creating a new event, which combines the two or the three. So, that number n is crucial. It prevents this universe, this evolving universe from being in a naive sense, Lorentz invariant. And then you ca

n only be the parent to such an event, a limited number of events, we usually use two or three, and then you stop being able to be a contributor to the causation of future events. And that gives us the limits, which tells us that the past then exists, the events that are characterized by a filled future, a future of so many new events in it, are then in the past, they no longer evolve, they no longer participate in evolving. That's why we say that the past no longer exists. But for us, it's exis

ting as just the part of the world which is dynamic. Okay, so that's how we get started. This is a causal set. A causal set is a bunch of events connected by causal connections. And this is more what we need for a causal set. For an unsteady causal set, we need each event to have a total momentum energy, which it collects from the events in its past through the events passing across causal relations. So you have to satisfy all the constraints implied by the conservation laws on the causal relati

ons. And let me… Okay, there we are. So this is more like what an event in a causal, an energetic causal set looks like. We have an event i, it's caused by events i, m, and j, which sends this particular amount of energy momentum. And it causes two new events, m and l, which it sends out that momentum and energy. Here's what it looks like in more detail if you play with them. So this is the summary again. So let me just emphasize what's in the here. The universe is made up of nothing but partial

views of itself. The universe is just itself, viewing itself, interacting as it creates new events, creates novelty, and goes to the future. Okay? And now let me skip a couple more. This is this I said before. We replace the idea that systems are more likely to interact if they're nearby in the background of space-time with systems are more likely to interact if they have similar views of their causal paths. And that's the basic equation of motion that we're constructing the world with. So how

does space-time emerge? How do relativistic space-time emerge? How do interactions emerge? I think these are in the details. And let me just point out essentially what's happening. What's happening is that if you have two events connected causally, then you have the event that before one of them, events after the second one, and they emerge a space-time, a region of space-time. If you can embed those triple or quadruple of events together in the space-time of low dimension. And we have lots of d

etails about how that works. I think I don't want to bore you with the details, but what you end up with is defining the theory through a kind of path order, path order, but it's simply a function of integration over the past processes. So we call it the past integral. And this integral is the fundamental definition of the theory. We represent conservation laws by exponentiating them as people, particle physics know well. So, and we write down the complete theory because of the dimensions that w

e use. There's no h bar, there's no space-time, there's no commutation relation, there's no uncertainty principle. This is the full statement of the laws. And again, they produce outcomes which are sometimes definite, and therefore the world is partly definite and it is personally causal, but it's not fully definite. And we, we, we exponentiate, we calculate, and off we go. But let me just come to the, to the point of how, just to hint how we get classical physics. Classical physics appears from

the spatially stationary space phase approximation and the details of that. If the theory is semi-classical, then it will give you a picture of relativistic particles moving in a relativistic space-time. I haven't input any space-time geometry, but I have input the geometry of a momentum space, which was hiding in some of the formula I used to derive the conservation laws. And I think I'm ready to go on to quanta. There's of course much more one can do with this. Um, let me mention that the las

t step in the definition of the theory is the imposition of the potential energy. The kinetic energy is defined by the conservation laws as in all good theories. The potential energy is defined by measuring the variety of spatial slices. There’s slices that are present dynamically with each other. And that has an amazing property, which I didn't know for several years of studying it. But that function, when you take a non-relativistic limit, becomes exactly the moment potential. Well, this funct

ions, the variety, it's some over triples of events and compare them in pairs, coming over all the pairs in those three events. And that turns out to be exactly the bone potential that you need to turn a functional and phase space into quantum mechanics. And that's the last physics I'm going to discuss. Um, much more to say about that. And so now let me talk about qualia The view that we've discussed, when does it, we want to take the view that it develops a dynamical theory, a dynamical relativ

e of quantum mechanics that has two laws as quantum mechanics does, but keeps them both realist. So the theory is sometimes in the faith, sometimes in a situation where it has precedence. What that means is that the events trying to guess its future, as which events are tested future of it, has two possibilities. It has the possibility that there is much precedence in the statement of the histories so that we can just look to the Schrodinger equation and write down how the probability distributi

ons evolve. But there are other situations where there's no precedent. And in the situation where there's no precedent, the universe must somehow choose its future without that choice being presented, precedented or determined. And that's how the universe is partly determined, partly free, and consciousness, we believe has to do with those parts of the universe which are partly free. And that's why our universe has also two kinds of evolutions, one of which is determined and comes from the Schro

dinger equation. The other is free because there's no precedent for them. There are some papers on this. So let me talk to its consequences. So this repeats what I said, this is my first hypothesis. There are in quantum theory two very different kinds of events, precedented or unprecedented events. Or you can call them ordinary quantum events versus novel or unique quantum events. The second hypothesis, the routine events are described to their approximation by ordinary quantum mechanics. They'r

e most of the time what the universe is doing and they result in the universe is partly determined. Our third hypothesis is that novel events, events that don't have a precedent, will require some way to construct the future, but it can't construct a determined future. Our fourth hypothesis, whoops, going the wrong way. The fourth hypothesis is that only views of novel or unique events can have no precedent or copies in the past, and these are the correlates of conscious perception. And I think

I'm done. The fifth hypothesis is that often there are situations where there's a choice among some situations where there's a one-dimensional continuum of states or parameters, and these are why you have energy coming into the perception of color and so forth. Well, that's a complicated matter. So I think I'm done. There's lots more to describe, but let me stop here and thank the audience for its patience and its open-mindedness. Thank you. Lee, thank you very much. In fact, you've ended almost

exactly on time because we've got roughly 10 minutes for questions. Again, can I just kick off, Lee? I mean, obviously this is an approach that relates to quantum gravity. We've just heard from George about the arguments for an evolving block universe. Does your sort of approach give any insights into whether you have an evolving block universe, or is it just a different sort of question? Well, our detailed dynamics, when we put them in, divide events. Let's start in the present because the fut

ure of events, events in our future, are simply events we don't have enough information about, can't have enough information about to completely predict. But supposing that you've made a measurement, making the measurement is dividing the possible future states as they occur into those that have the different labels, the different parameters that the Schrodinger equation would describe to them. And then you're just to the past of such an event, where such a division was made, and all you have le

ft is the branch where the universe evolved to. And that branch can no longer… We can draw pictures and speculate because that branch evolves classically to the past, given the information that we have. But it's not any more contributing to the quantum evolution, and therefore it might as well be dead. So we choose to simplify the universe and regard them as dead because such causal effects going to the past can never affect the future. Okay, thank you. So at this point I would like to ask any o

ther presenters, if present, if they would like to make a comment or ask a question of Lee. If not, we can go straight into the questions from the Q&A. So let me then read the first question from Q&A, Lee. You refer to the view of an event and its knowing of past events. Is this just a metaphor or do you actually attribute perceptual mentalistic properties to the events in the fashion of say Leibniz or Whitehead? Well, people have been asking this question since Leibniz and Whitehead, and I don'

t know that I'm any wiser than they are. That is, I'm, you know, once you kick off the dock and you're floating in the seas where consciousness and mental events are part of the picture, I feel quite lost. And I don't know any more than kick off the dock and pull in the sail and pray. But I mean, do you find the writings of Whitehead and people actually helpful in developing a physical approach? Or is it like a parallel? Whitehead and Russell were influential to me when I was a college student,

in which I kind of reading them, I kind of quote, with a little smile behind it, invented their view. And their view is, I think it's a little bit too easy just to say that everything has conscious aspects and classical aspects. And you say, I don't believe you've done anything. But it's suffice for my personal view to put me in the dark, to leave me in the dark for 30 or 40 years. So conversing with the people I mentioned, threw me back out in the dark again, made me realize I didn't know anyth

ing about it. Okay, thank you. We have another question from the floor. When associating novel events with consciousness, are you saying that novel states are fundamentally qualitative states? Question for Lee. Something like that, yes. Yes, because if we could measure them and make an association between the science, how you describe that new state, and do it with things which are numerically measurable, you're in the domain where you can calculate things about the future. So eventually, you ha

ve to have a discussion about the nature of mathematics. And my view on the nature of mathematics is that there are people who claim that anything in the universe has a mathematical description. So the universe as a whole corresponds to some mathematical object. So I have a quote proof that there can’t be a mathematical object that describes the world at this time. Because if there weren’t such a mathematical object, it would be possible to state after observing the universe what time it is. And

it's not in any absolute sense possible to do that. I don't think that there is any mathematical description of what we're looking for. Maybe a mathematical description, maybe we'll get it by successive approximations, something like that. I think there's something fundamentally non-mathematical about how the universe exists and evolves. Thank you. Lee, you made a reference to a recent paper you've written with Julian Barber. And this leads to the next question from the audience. By insisting o

n the primacy of the present, are you coming closer to Julian Barber's position that physics can but formulated without the passage of time? The English isn't quite right. The position that physics can not, can be formulated without the passage of time. Without the passage of time. I hope you're intending a joke when you said that the paper with Julian was recent. It's 1985 or something like that. But that interaction with Julian, the intense conversations we had over four or five years, then ce

rtainly completely set my direction and my understanding of physics at that time. And since Julian has been kind of always present, but often disagreed with, mentor. So are you agreeing with Julian? I don't agree with Julian. I don't agree. That's what I was assuming, because his famous book is in some sense on the non-existence of time. Right, but had Julian not written that book or been around, I probably wouldn't be here having this conversation. George, I think we just have time maybe for on

e more question. So would you like to comment? It seems to me that Lee is asking for a theory of the moving present. So firstly, the present is very special in his viewpoint and in agreement with me. But secondly, my philosophy is the following. I don't want uncaused causes. Now the atoms in this room were created in the interior of stars in the past. And so therefore, I want to say that that event in the past must have must be real, because it's something which affects me here and now in a very

material way. So my philosophy is in order to have no uncaused causes, the past must exist. That's the basis of my philosophy. Okay, I have no deep disagreement with that. But I would call the events in the past, because in the way we formulate the theory, they can have no direct influence on the present, we must influence the present through a series of steps. We call that non-existent. We call what's existed only those aspects of causal influences, which act immediately. And that's the way we

choose to try to set up the laws. I don't think it's a fundamental difference. Thank you, Lee. We've now almost exactly come to the end of the time. So many thanks, and we hope you can stay for the discussion session at the end of the day. I will stay. I'll be here in the background most of the time. Wonderful, thank you.