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Our columnist has just released a major book on the philosophy of time. Grant Bartley interviews him about Of Time and Lamentation.
Lovely to see you Professor Tallis, to talk about your new magnum opus, Of Time and Lamentation. What were your motivations for writing this book?
Well, it’s part of a much bigger project. As a secular humanist, I feel I’ve managed to liberate myself from supernatural accounts of humanity, but the alternative for many people is a naturalistic account – the idea that we’re just ‘pieces of nature’. One aspect of that is the notion that the natural sciences are ultimately going to give us a complete account, not only of the rest of the universe, but of ourselves in it. It’s this scientism that has been one of my targets over many years, and it’s one of the drivers for writing this book about time. There are other motives. But the scientific reduction of time to ‘little t’ is a very good example of where scientism gets us, and it’s a rather dismal place.
By t you mean representing time as a value rather than as something real?
I mean as a pure quantity of a variable; as a mere dimension, one of four dimensions, the other three being space – x, y, and z – as a result of which our notion of time is seriously impoverished. The scientific account of time is of course extraordinarily useful. It has enabled us to predict physical events and control them in a way we could not have imagined in a prescientific age. The danger is that this success leads us to believe that the physics of time, or time as seen in physics, is the last word on the subject – that physics of time is its metaphysics as well.
Think about the things you can do to t. You can multiply it by itself. You can put it under another parameter as a denominator, as when you’re measuring velocity [= d/t, Ed]. You can marry it up to the speed of light to measure interstellar distances, and so on. Now these are the kinds of things you can do to time when it’s been stripped of all that we associate with it in human life. But think of trying to put a bargain break weekend as a denominator, or multiplying a happy afternoon by itself. It’s not possible, and it makes you realise what has been stripped away from time when it has been reduced to t.
So the scientific conception of time as a quantity doesn’t relate to the human experience of it?
It doesn’t, and in many ways we often think that clock time is the last word – so that if I quarrel with the clock about how much time has passed, then the clock in the end must be right. But of course, the clock only measures quantity and time is much more rich and complex than that. So the book first of all addresses the reduction of time to a quasi-spatial dimension, as in relativity theory, made explicit in Minkowskian four-dimensional space-time. Ultimately this geometrises time, folding it into the geometry of space – and as a result much is lost. In the book, I examine how time seems to be reducible to t only if we somehow erase the observer, if we forget that in order for time to be measurable, it has to be measured by someone. So even on its own terms, the physics of time gives an incomplete account of its operations.
I want to put the human experience of time at the centre of ‘time’. That’s quite difficult, because if you seem to say that the very existence of time depends on humanity, then you’re rejecting an awful lot of what we know from science, particularly that there was a temporal sequence of events before there was any consciousness, never mind human consciousness. The Big Bang came before the emergence of the planets, and the Earth came before there was life, and life came before there was conscious life. So clearly time antedates human consciousness. So I’m not implying that physical time is internal to human consciousness, because that would then put me in a very difficult position in regards to what we know about the history of the universe.
Raymond Tallis portrait by Gail Campbell, 2017
How does the physicists’ mathematical picture relate to reality itself?
That’s a really interesting question and one that I must address, because if I’m saying that t isn’t really the essence of time, I’m claiming that the quantitative approach to the world, although extraordinarily effective, doesn’t fully grasp reality. In the book I explore three views of why mathematics has been so successful in physics, and why physics has been such a powerful science. The first is that mathematics is just a very useful tool for dealing with a particular aspect of reality, namely its quantities. The second is the much bolder claim that, essentially, mathematics is not a partial portrait of the world, but is the complete portrait of the world, the most faithful portrait. And finally, there is industrial-strength Pythagoreanism, which says essentially that the world consists of mathematical objects. In the end I think I’m with the majority of physicists in seeing mathematics just as an incredibly powerful tool, giving quantitative answers to quantitative questions. The world, however, doesn’t consist solely of quantitative answers to quantitative questions. Mathematics is very powerful because it reduces places to decimal places, but places aren’t decimal places; they’re more than that. Those who think that the world consists of mathematical objects are making the famous mistake of confusing the map and the terrain.
Why do scientists so resolutely want to hang onto time as a pure quantity, do you think?
It’s part of the whole project of physical science from Galileo onwards, that it takes quantities to be the real deal, as it were, and dismisses qualities as things that are merely of the mind and are not fully real. Don’t mistake me, I think physics is the greatest cognitive achievement of humanity, and it has delivered many practical benefits for us in terms of life expectancy, health expectancy and so on. But what it doesn’t deliver is a rounded account of even the material world, even less of the human world, the world in which physicists live and do their physics. That’s why the second part of the book is devoted entirely to lived time. I look at the three tenses, past, present and future, and also glance at eternity as well, because I think that’s quite interesting. I look at the tenses in turn, after defending tensed time against the scientific claim that tenses are illusory, and against some philosophers who think that tensed time is simply a by-product of the relationship between language and the world. They think that when we’re talking about the past we’re really talking about an event that’s prior to the statement that is being made. For example, if I say that something happened last week, what I’m really saying is that that event happened a week before my present utterance. I don’t think that reduction works, for all sorts of reasons that I discuss. So I defend tensed time against the philosophers, and against the physicists, and then examine the tenses in turn. I begin with what seems at first sight the easiest one, which is the present.
Is there a present, and if so, is it ‘specious’?
To me the most specious notion is the idea of the durationless instant, or atom of time. I think it was William James who pointed out that no-one would spontaneously think that time was made of durationless instants. The instant, as A.N. Prior said, is purely a construct.
If you look at the present, at ‘now’, it is quite puzzling. Since Classical times, people have said the present is the line between that which has not yet happened and that which has already happened, and the line, as it were, has no width. And if you look at time as seen by physicists, it is composed of unextended points. But the present isn’t made out of durationless instants. Any given moment of consciousness is already reaching into the future and drawing on the past. This is something that was made much of by phenomenologists such as Husserl, but I develop this idea to a greater degree.
Could you tell us what you mean by ‘reaching into the future’ and ‘drawing on the past’?
As I’m looking at you now I recognise your face. Your face makes sense to me because of my past experience, and because of the reason we’ve come to meet, which makes sense of what is happening. The very intelligibility of the present draws on the past. But in addition, the intelligibility of the present arises from its being pregnant with what’s going to happen next. Our being here gives me a sense of what’s going to happen in the next few minutes, and beyond. The intelligibility of the present not only draws on the past, but also on the ongoingness of the present, of what’s going to happen next, and indeed, what is expected of me.
How do the past and the future relate to now?
This is one of the most interesting questions: What is the status of tomorrow, today? What of tomorrow is here already? There are certain items that definitely are here already. For example, there are ongoing processes, that’ll still be ongoing in five minutes’ time. There is the room in which we are sitting, which will be the furniture of tomorrow as well as of today. What isn’t already existing are future events. Of Time & Lamentation discusses ‘logical fatalism’. This derives from an interesting argument by Aristotle that goes as follows: either it’s true that there will be a sea battle tomorrow, or it’s true that there won’t be a sea battle tomorrow. If one of these statements is true, it must be true already – in which case, the future is already fixed. The question is, are we logically stitched up? In other words, is the future already determined?
The way one deals with this is to look very critically at the assertions that are made in the argument. The reality is, when you’re talking about a future sea battle, you’re not talking about any actual event, you’re talking about a class of possible events, and those events couldn’t all be possible together, because one sea battle might include Able Seaman Jones dying and another sea battle Able Seaman Jones not dying. So clearly, the referent of the propositions in the argument couldn’t be a real event. But the future still has a reality in terms of present, stable, objects, and ongoing processes.
To come back to the present, just as the present sometimes seems to be squeezed out by the past and the future, the opposite danger is that the present swallows up the other tenses. There is a strong philosophical movement called ‘presentism’, which is the idea that only that which presently exists is real, and therefore there is only one tense, the present tense. But if the only reality were the present, then how could there be things that are true of, or false of, the past? How could I say truly that Socrates was an Athenian, and say falsely that Socrates was an Englishman? If the past has no reality, there can be no truths about it, because ‘truth supervenes on being’. So the past has its own reality, and it’s a very complex reality. There’s the past of direct recall, and then the past of the whole lattice of facts that we, the human race, curate collectively – the past of history.
Does tensed time necessarily require a human observer, or a conscious observer at least?
Yes, it certainly does, but that doesn’t mean it has a second-rate type of existence. It doesn’t make it any more second rate than colours, for example, which also depend on observers.
Does it make sense to ask about ‘time itself’ as opposed to a sense of time?
I think that’s the most difficult question, and the most interesting one. I do explore it at great length, and in the end, I haven’t reached a resolution. But let me throw out a few thoughts. It seems to me that the notions of ‘earlier’ and ‘later’ must presuppose consciousness. Thunder isn’t aware of being later than the lightening. It doesn’t connect itself with the lightening. The thunder occurs when it occurs, the lightening occurs when it occurs, there is no ‘earlier’ or ‘later’. There isn’t a sequence except when that sequence is observed by an individual who is linking the two events. If being earlier or later were a constitutive or intrinsic property of events, then the world would be a real mess, because each event would be earlier than millions of events and later than millions of other events. So even earlier-and-later time – so-called ‘B-Series time’, as John McTaggart called it – does seem to require consciousness to bring together two events, to locate them in a temporal relation. It’s much easier to deal with tensed time: it’s perfectly obvious that past, present and future do appear to require human consciousness. Having said that, we know that there are objective sequences of events that took place before consciousness, as we discussed. So we have the problem of human time being contained if you like in physical time; and physical time being extracted from the universe by human consciousness. This is a situation that Quine refers to as ‘reciprocal containment’.
In an observerless universe, could there still be an order of events, but not in terms of a temporal order as we understand it? So you could say that events are in spacetime ordered in a particular sequence, but it’s only when you put a human being in that you get what we might call time?
Maybe. It seems that if you try to remove the human observer, and you try to assume what Nagel called a ‘view from nowhere’ – an impossible view, because it would be a view without a viewpoint – you would have the sum total of the space-time continuum. But one doesn’t know what the space-time continuum is in the absence of an observer. Some philosophers have said that everything co-exists in the space-time continuum, which is nonsense, because that would mean that opening the door and closing the door were occurring at the same time; or perhaps, not occurring at any particular time, or (as Herman Weyl suggested) not occurring at all.
What about an eternal experience? Is that idea coherent?
The whole idea of eternity is a difficult one. Both religious and non-religious notions of eternity have lots of problems. First of all, what is eternity? Is it everlastingness – endless time – or is it timelessness? That ambiguity becomes particularly pressing when we think about people entering eternity, either at a particular moment, or at the end of their lives – because you then have to ‘enter’ eternity, which may be timeless, at a particular time, which is clearly a paradox. And by the way, living in eternity is a pretty bleak business, because in order for things to go on forever they mustn’t change, and if there’s no change, nothing as messy as metabolism can happen, and nothing as messy as needs can be felt. I don’t think unbelievers like me are missing out on much.
Do you not think it might make sense for there to be a higher dimension of time from which you could see the flow of time?
This seems to invite the question: ‘If time is flowing, how quickly is it flowing, and what is it flowing in?’ And the answer is, ‘Well, it’s flowing at one second per second; and as for what it’s flowing in, it must be flowing in second-order time.’ Very unsatisfactory. You can’t have the kind of measure that has the same dimension on the numerator and the denominator [t/t], because they cancel each other out. Someone might say, ‘So time doesn’t flow: that must mean that it’s static, and indeed, the universe is static.’ The answer is no: just because something isn’t flowing doesn’t mean to say it’s static. Likewise, just because prime numbers aren’t very nutritious doesn’t mean that they’re a very poor source of nutrition. I believe it is a category mistake to think of time as flowing – or as static. So you may ask, why do we find the idea of time as flowing irresistible? It’s because we project into time itself the dynamism of events, including the events by which we measure time. So we watch the clock hand moving, and we think that’s time flowing.
If ‘flowing’ isn’t a good metaphor, what would be a good way of phrasing the change or movement of or through time?
I can give you any number of bad metaphors: the idea of time as a growing block, time as a moving spotlight, and so on, but none of these work for all sorts of reasons which I go into in the book. I think we’ve got to do without metaphors. Basically, we scrape off the metaphors, and we see what we’re left with. Then we start by looking for some very pared-down, parsimonious definition of time – and actually, we fail again. Look at some of the definitions that have been given: time is our perception of the sequence of events; time is the direction of causation; or time is that which permits change without contradiction so that I can say of you that you’re in London and you’re in Edinburgh, and that’s not a contradiction because you’re in London one time and Edinburgh another. But if you look at all those definitions, they end up being circular. For example, the one that says time is that which permits change as the world cannot have two states at once, you have helped yourself to ‘at once’, a temporal notion. The idea that time is our perception of the sequence of events is even more obviously circular: the ‘sequence’ is a ‘temporal sequence’. There’s no non-circular definition of time. This doesn’t worry me, because the very fact that it is something real and sui generis [uniquely of its own kind] means it can’t be reduced to anything else.
Maybe we can say we know what the movement of time is because we experience it?
I’m not too sure we do experience the movement of time. We notice events which are dynamic, and we also notice a certain subgroup of events, which are the movements associated with the measurement of time – with clocks. But I don’t think we have a direct experience of the movement of time in the way in which we have a direct experience of movement in space. Rather, we experience that certain things happen at a particular time; that certain things take a certain time; and that something happened before something else; and that something was in the past and that other something was in the future. But there’s nothing non-temporal, as it were, that these things add up to.
Is time inextricably linked to change?
Well there have been lots of thought experiments imagining a world in which all change stopped, including some very cunning ones, involving somehow imagining that you can look at what’s happening in that world. If everything stopped universally at once, then no-one could make observations, so Sydney Shoemaker suggests we should imagine a situation where a third of the world freezes periodically, and then another third freezes periodically, and then the third third of the world freezes periodically, but they have a different periodicity of freezing, such that once in sixty years the whole world froze. The question is, would there then be a change in time? And there are reasons for thinking not. First of all, there would be no measures of changing time. Secondly, there would be no way of determining the period for which time is frozen: there would be no difference between an instant and an eternity. So it would seem that in some sense time is inseparable from change – but allowing for the fact that time is equally present in things that are stable.
How is human freedom linked to time?
I think tensed time is absolutely central to human freedom. Creatures who live and experience tensed time – uniquely, human beings – are not identical with the physical moment that they are in. So as I’m sitting here now, the very intelligibility of the experience I’m having means I am to some extent rooted in my past, and reaching towards a future. And not being identical with a particular moment in the physical world is the very seed and source of our freedom.
To me this links up with what Sartre said about a human being being a ‘for-itself’ and not an ‘in-itself’, meaning that consciousness is a type of freedom from material reality.
There’s certainly a link. But his view was too general; I look at freedom more specifically, and in fact I look at real actions and real agency. Firstly, any real action has to make sense to the agent; and secondly, it wouldn’t have occurred if it didn’t make sense to the agent. Basically, whenever I act, I’m putting together a very large number of physical events that wouldn’t have co-occurred if it hadn’t been for the sense from the past of what I want to do, and the sense of the coming future of what I want to achieve. This is that ‘not being identical with the moment’, which is, if you like, an instantiation of Sartre’s notion of the for-itself not being what it is and being what it is not.
How was your thinking about time influenced by the ideas of time of other horosophers, such as Immanuel Kant, John McTaggart, A.N. Whitehead or D.H. Mellor?
I found that Kant’s assumption that time was one of the ‘forms of sensible intuition’ wouldn’t stand up against the fact that we know there are genuine temporal sequences before human consciousness. When it comes to McTaggart, I disagree both with his rejection of tensed time, and his use of that rejection to deny the reality of time. D.H. Mellor was one of my favourite interlocutors, as he writes so beautifully and succinctly. We disagreed on tensed time, and I also disagreed with his notion that time is the causal dimension of space-time.
Before I finally ask what is time, can I ask you, what is time not?
Having scraped off all the metaphors and having restored living time, I say, well, let’s look at some definitions. One definition is, time is our perception of the sequence of events; but that has problems, as we’ve discussed. Secondly, time is something that permits change. Here time is purely permissive for, as it were, logical reasons: it allows something to be both round and square by being round at one time and square at another. But this definition assumes we have the notion of time built in already: basically it says that object A can be red at time t21 and blue at t2. So we’ve already used time in our definition. Also, ‘permissive time’ is dangerously close to the idea that time itself is a cause. If time had causal efficacy, then every event would have two causes: one would be its own private cause, of which it is an effect, and the other would be time. So that’s an overdetermination of causes. Another definition is that, as Richard Feynman jokingly said, time is what happens when nothing else happens. This is unhelpful, because essentially it assumes we can have time in the absence of change and events. And there’s a whole pile of other definitions of time. Their failure makes a Wittgensteinian approach to the definition of time appealing. Nevertheless, I resist the notion that time is a term that refers to a cluster of concepts that may have a family resemblance but don’t add up to anything ‘in itself’. Wittgenstein’s approach is more compelling when we apply it to items such as games. His question was, what do the Olympic Games and Ludo have in common that makes them both games? And his answer was, not very much, so we’re foolish to think that there’s something shared by all games that makes them games, even if they do have family resemblances one to another. But I think there is something corresponding to time. It’s not a mere construct out of the shadows cast by words. But it’s none of those things I’ve just discussed. In my long look at time I try to put together all the different things we may say about time, all the ways of approaching it, and paint a portrait that does justice to its complexity. I conclude that time is both real and irreducible to other things. I’m very much with Lee Smolin, who said that if anything is absolutely fundamental in the universe, it is time.
That brings us to the $64,000 question: What is time, Professor Tallis?
Time is not reducible to anything else, and therefore can’t be captured in a definition. It has many aspects and it cannot be translated into a mere dimension comparable to length. Even those who deny the importance of its lived reality must accept that it is never going to be simple, never just one thing. The most ardent reductionist has to accept the difference between temporal order, temporal duration and temporal location. This is evident when we consider real events. Agincourt occurred after the Battle of Hastings; Agincourt lasted for a day; and Agincourt took place in 1415. Complexity beyond ‘little t’!
• Grant Bartley edits Philosophy Now.
• Raymond Tallis’s new book Of Time and Lamentation: Reflections on Transience was published in May 2017 by Agenda Publishing.