The End of Time: The Next Revolution in Physics

CHAPTER 2

Time Capsules

THE PHYSICAL WORLD AND CONSCIOUSNESS

The discussion in Chapter 1 prompts the question of how our sense of the passage of time arises. Before we can begin to answer this, we have to think about another mystery – consciousness itself. How does brute inanimate matter become conscious, or rather self-conscious?

No one has any idea. Consciousness and matter are as different as chalk and cheese. Nothing in the material world gives a clue as to how parts of it (our brains) become conscious. However, there is increasing evidence that certain mental states and activities are correlated with certain physical states in different specific regions of the brain. This makes it natural to assume, as was done long ago, that there is psychophysical parallelism: conscious states somehow reflect physical states in the brain.

Put in its crudest form, a brain scientist who knew the state of our brain would know our conscious state at that instant. The brain state allows us to reconstruct the conscious state, just as musical notes on paper can be transformed by an orchestra into music we can hear. By the ‘state’ of a system, say a collection of atoms, scientists usually mean the positions of all its parts and the motions of those parts at some particular instant. It is widely assumed that conscious states, in which, after all, we are aware of motion directly, are at the least correlated with (correspond to) brain states that involve not only instantaneous positions but also motions and, more generally, change (associated with flow of electric currents or chemicals, for example). This is a natural assumption. Our awareness of motion and change is vivid and often exciting: think of watching gymnastics, or the 100-metre sprint final in the Olympic Games. We suppose that the impression of motion must be created by some motion or change in the brain.

However, if the physical processes in the brain are controlled by laws like Newton’s, such an assumption runs up against the problem that they distinguish no direction of time. Figure 1, with its impossibility of saying in which direction time flows, makes this clear. It is no help to go from its three particles to billions of them. Observed effects should have a real cause. The chain from cause to effects may be quite long and take surprising forms, but a cause there must be. It is unsatisfactory to suppose that we have a direct awareness of an invisible flow of time. Our sense of the passage of time and, even more basically, of seeing motion and knowing its direction, ought to have a cause we can get our hands on.

The lack of time direction in the bare laws of motion led Boltzmann to a remarkable suggestion (quoted in the Notes). As we have seen, Newtonian systems can enter highly ordered phases. These are exceptionally rare periods separated by ‘deserts’ of monotony. Nevertheless, every now and then a system will enter one. Its entropy will go down, reach a minimum, and then start to increase.

We should not think of this happening in a definite direction of time. Instead, we should picture the states of the system strung out in a line, as in Figure 1, which we could ‘walk along’ in either direction. Every now and then, with immense stretches between them, we will come upon regions in which the entropy decreases and the order increases. Then the entropy will start to increase again. Someone ‘walking’ in the opposite direction would have the same experience. Now, such a line of states can represent the entire universe, including human beings. Since we are very complicated and exhibit much order, we can be present only in the exceptional regions of low entropy.

Boltzmann’s suggestion, startling when first encountered, was that conscious beings could exist on either side of a point of lowest entropy, and that the beings on both sides would regard that point as being in their past. Time would seem to increase in both directions from it. In this view, time itself neither flows nor has a direction; it is at most a line. It is only the instantaneous configurations of matter, strung out like washing on the line, that very occasionally suggest that time has a direction associated with it. The direction is in the washing, not the line. What is more, depending on the position in the line, the ‘arrow’ will point in opposite directions.

This, then, gives a genuine cause for our awareness of motion and the passing of time. The conscious mind, in any instant, is actually aware of a short segment of the ‘line of time’, along which there is an entropy gradient. Time seems to flow in the direction of increasing entropy. Interestingly, consciousness and understanding are always tied to a short time span, which was called the specious present by the philosopher and psychologist William James (brother of novelist Henry). The specious present is closely related to the phenomenon of short-term memory and our ability to grasp and understand sentences, lines of poems and snatches of melody. It has a duration of up to about three seconds.

The key element in Boltzmann’s idea is comparison of structures. There needs to be qualitative change in the brain patterns along a segment of the ‘line of time’. If the brain pattern in each instant is likened to a card, then the patterns become a pack of cards, and our conscious experience of time flow arises (somehow) from the change of pattern across the pack. Though we may not understand the mechanism, the effect does have a cause.

To summarize: Newtonian time is an abstract line with direction – from past to future. Boltzmann keeps the line but not the direction. That belongs to the ‘washing’. But do we need the line?

TIME WITHOUT TIME

Perhaps not. The brain often fools us. When we first look at certain drawings, they appear to represent one thing. After a while, the image flickers and we see something different. The reason is well understood: the brain processes information before we get it. We do not see things as they are but as the brain interprets them for us. There are very understandable reasons for this, but the fact remains that we are often fooled by such ‘deceptions’.

Could all motion be a similar deception? Suppose we could freeze the atoms in our brains at some instant. We might be watching gymnastics. What would brain specialists find in the frozen pattern of the atoms? They will surely find that the pattern encodes the positions of the gymnasts at that instant. But it may also encode the positions of the gymnasts at preceding instants. Indeed, it is virtually certain that it will, because the brain cannot process data instantaneously, and it is known that the processing involves transmission of data backwards and forwards in the brain. Information about the positions of the gymnasts over a certain span of time is therefore present in the brain in any one instant.

I suggest that the brain in any instant always contains, as it were, several stills of a movie. They correspond to different positions of objects we think we see moving. The idea is that it is this collection of ‘stills’, all present in any one instant, that stands in psychophysical parallel with the motion we actually see. The brain ‘plays the movie for us’, rather as an orchestra plays the notes on the score. I am not going to attempt to elaborate on how this might be done; all I want to do is get the basic idea across. There are two parts to it. First, each instantaneous brain pattern contains information about several successive positions of the objects we see moving in the world. These successive positions need correspond only to a smallish fraction of a second. Second, the appearance of motion is created by the instantaneous brain pattern out of the simultaneous presence of several different ‘images’ of the gymnasts contained within it (Figure 2). This happens independently of the earlier and later brain states.

Figure 2 My explanation of how it might be possible to ‘see’ motion when none is there is illustrated in this chronophotograph of a sideways jump. My assumption is that the pattern of the atoms in our brain encodes, at any instant, about six or seven images of the gymnast. The standard ‘temporal’ explanation is that the gymnast passes through all these positions in a fraction of a second. My idea is that when we think we are seeing actual motion, the brain is interpreting all the simultaneously encoded images and, so to speak, playing them as a movie.

This proposal is not so very different from Boltzmann’s idea that the sense of motion is created from several qualitatively different patterns arranged along the ‘line of time’. Instead, I am suggesting that it is created by the brain from the juxtaposition of several subpatterns within one pattern. The arrow of time is not in the washing line, it is not in several pieces of washing, it is in each piece. If we could preserve one of these brain patterns in aspic, it would be perpetually conscious of seeing the gymnasts in motion. If you find this idea a bit startling, I am glad because I find it does bring home the ‘freezing of motion’ that I think we have to contemplate. In fact, since brain function and consciousness are fields in which I have no expertise, I would like you to regard this suggestion in the first place as a means of getting across an idea, the main application of which I see in physics.

To that end, I want to introduce the notion of special Nows, or time capsules, as I call them.

TIME CAPSULES

By a time capsule, I mean any fixed pattern that creates or encodes the appearance of motion, change or history. It is easiest to explain the idea by examples, for example the Ariel in the storm in Turner’s painting. Although they are all static in themselves, pictures often suggest that something has happened or is happening – with a vengeance in this painting. But in reality it simply is. I know no better example of something static that gives the impression of motion.

In pictures, the impression is deliberately created. Much more significant for my purposes are time capsules that arise naturally and have to be interpreted, by the examination of records they seem to contain. Records, or apparent records, play a vital role in my idea that time is an illusion. I use records primarily in the sense of, for example, fossils, which occur naturally and are interpreted by us as relics of things that actually existed. Less directly, all geological formations, rock strata in particular, are now invariably interpreted by geologists as constituting a record (to be interpreted) of past geological processes. Finally, there are records that people create deliberately: doctors’ notes, minutes of committee meetings, astronomical observations, photographs, descriptions of the initial and final conditions of controlled experiments, and so on. All such things, and many more, I call records. My position is that the things we call records are real enough, and so is their structure. They are the genuine cause of our belief in time. Our only mistake is the interpretation: time capsules have a cause, but time is no part of it.

Let me now attempt a more formal definition. Any static configuration that appears to contain mutually consistent records of processes that took place in a past in accordance with certain laws may be called a time capsule. From my point of view, it is unfortunate that the dictionary definition (in Webster’s) of a time capsule is ‘a container holding historical records or objects representative of current culture that is deposited (as in a cornerstone) for preservation until discovery by some future age’. I do not mean that. But we have all had the experience of walking into a house untouched by historical development for decades or centuries and declaring it to be a perfect time capsule. This, I believe, happens to us in each instant of time we experience. The only difference is that we experience our current time capsule, not someone else’s. And we are mistaken in the way we interpret the experience.

It is important for me that, as I point out in the next section, the phenomenon of time capsules is very widespread in the physical world, and is not restricted to our mental states and experiences. In addition to my caveat at the end of the previous section, I should emphasize that I am not claiming consciousness plays some remarkable novel or extraphysical role in the world. Unlike Roger Penrose in his best-seller The Emperor’s New Mind, I am not suggesting that there is any ‘new physics’ associated with mental states. There may be, but that is not part of my time-capsule idea. However, I do believe we have to think carefully about the role of consciousness in the picture that we form of the world.

First, all knowledge and theorizing comes to us through the conscious state. If we want to form an overall picture of things, we cannot avoid allotting a place to consciousness. It is necessary for completeness: we have to consider ‘where we stand’. This is closely related to a second factor. Viewed as a physical system, the brain is organized to an extraordinary degree. It is vastly more complicated and intricate than the air we breathe or the star clusters we see through telescopes. There may not be any locations anywhere in the universe that are more subtly and delicately organized than human brains. There is not merely the brain structure as such, but also the distillation of accumulated human experience and culture that we carry in our brains. But this very organization may be giving us a distorted picture of the world. If you stand, like Turner bound to the Ariel’s mast, in the tornado’s maelstrom, you might well suspect that the universe is just one great whirlpool.

The lesson we learned from Copernicus, Kepler and Galileo is here very relevant. They persuaded us, against what seemed to be overwhelming evidence to the contrary, that the Earth moves. They taught us to see motion where none appears. The notion of time capsules may help us to reverse that process – to see perfect stillness as the reality behind the turbulence we experience.

Stand, as 1 have with a daughter, and look at Jupiter against the winter stars. Every clear frosty night we stood on the utterly motionless Earth – as it appeared to our senses – and watched through the winter as Jupiter, high in the sky, tracked night by night eastwards against the background of the stars. But then Jupiter slowed down, came to a stop, and went backwards in the retrograde motion that so puzzled the ancients. Then this motion stopped, and the eastwards motion recommenced. In all this Jupiter moved, not us. We could see it with our eyes. Seeing is believing. But what did Copernicus say? We must be careful not to attribute to the heavens (Jupiter) what is truly in the Earth-bound observer. I could persuade my daughter that the motion of the Earth, not of Jupiter, gives rise to the retrograde motion. To interpret events, we must know where we stand and understand how that affects what we witness. But we observe the universe from the middle of a most intricate processing device, the human brain. How does that affect our interpretation of what we see?

EXAMPLES OF TIME CAPSULES

As a first example, we can stay within the brain but consider long-term memory. A game we sometimes play at Christmas brings out the importance of mutually consistent records held in structures. Fifty events in recent world history are written down on separate cards without dates attached. Players are divided into teams and given the cards jumbled up. The challenge is to put them in the correct chronological order. The only resource each team has to attack the task is their collective long-term memories, which every good realist (myself included) will surely agree are somehow or other ‘hard-wired’ into their brains. How each team fares depends on the consistency of its members’ recollections – the records in their brains.

This example shows clearly that all we know about the past is actually contained in present records. The past becomes more real and palpable, the greater the consistency of the records. But what is the past? Strictly, it is never anything more than we can infer from present records. The word ‘record’ prejudges the issue. If we came to suspect that the past is a conjecture, we might replace ‘records’ by some more neutral expression like ‘structures that seem to tell a consistent story’.

The relevance of this remark is brought home by the sad examples of brain damage that takes away the ability to form new memories but leaves the existing long-term memory intact. One patient, still alive, retains good memory and a sense of himself as he was before an operation forty years ago, but the rest is blank. It is possible to have meaningful discussions about what are for him current events even though they are all those years away, but the next day he has no recollection of the discussion. The mature brain is a time capsule. History resides in its structure.

After our own brains, the most beautiful example of a time capsule that we know intimately is the Earth – the whole Earth. Above all, I am thinking of the geological and fossil records in all their multifarious forms. What an incredible richness of structure is there, and how amazingly consistent is the story it tells. I find it suggestive that it was the geologists – not the astronomers or physicists – who first started to suggest an enormous age for the Earth. They were the discoverers of deep time, which did start as conjecture. And it was all read off from rocks, most of which are still with us now, virtually unchanged from the form they had when the geologists reached those conclusions. The story of the antiquity of the Earth and of its creation from supernova debris – the Stardust from which we believe we ourselves are made – is a story of patient inference built upon patient inference based upon marks and structures in rocks. On this rock – the Earth in all its glory – the geologists have built the history of the world, the universe even.

What is especially striking about the Earth is the way in which it contains time capsules nested within time capsules, like a Russian doll. Individual biological cells (properly interpreted) are time capsules from which biologists read genetic time. Organs within the body are again time capsules, and contain traces of the history and morphogenesis of our bodies. The body itself is a time capsule. History is written in a face, which carries a date – the approximate date of our birth. We can all tell the rough age of a person from a glance at their face. Wherever we look, we find mutually consistent time capsules – in grains of sand, in ripe cherries, in books in libraries. This consistent meshing of stories even extends far from the Earth and into the outermost reaches of the universe. The abundances of the chemical elements and isotopes in the gas of stars and the waters of the oceans tell the story of the stars and a Big Bang that created the lightest elements. It all fits together so well.

For me, two facts above all stand out from this miracle of nature. If we discount the direct perception of motion in consciousness, all this fantastic abundance of evidence for time and history is coded in static configurational form, in structures that persist. This is the first fact, and it is ironic. The evidence for time is literally written in rocks. This is why I believe the secret of time is to be unravelled through the notion of time capsules. It is also the reason why I seek to reduce the other hard and persistent evidence for time and motion – our direct awareness of them in consciousness – to a time-capsule structure in our brains. If I can make such a structure responsible for our short-term memory – the phenomenon of the specious present – and for the actual seeing of motion, then all appearances of time will have been reduced to a common basis: special structure in individual Nows.

The second fact that needs to be taken on board is the sheer creativity of Nature. How does Nature create this rich, rich structure that speaks to us so insistently and consistently of time? How could it and we come to be if there is no time? The appearance of time is a deep reality, even without the motion we see and the passage of time we sense in consciousness. It is written all over the rocks. Any plausible account of the universe must, first and foremost, explain the existence of the structures we see and the semantic freight (i.e. the seemingly meaningful story) that they carry.

If we can explain how they arise, time capsules offer the prospect of a much more radical explanation of the properties of time than Boltzmann’s account of the origin of its arrow. To explain the appearance of an arrow, he still had to assume a succession of instants strung out along a ‘line of time’. I have already suggested that the line may be redundant. The inference that it exists can emerge from a single Now. The instant is not in time – time is in the instant.