Postscript to "Time, Science and Philosophy"

Although it is only two years since the publication of this book, much of it was written more than six years ago. In this essay I consider a few respects in which it might have differed if it had been written today.

Numerous papers have appeared in recent years which claim to threaten some of our established theories in Astronomy and Physics, and new slants on philosophical thought are constantly being offered in journals such as Mind. But on re-reading my book, I am reassured to find that there is little of it I would wish to change. There is an increasing tendency in the sciences for authors to rush into print with sensational discoveries before they have examined the evidence critically enough, or assessed the consequences. Often the theories which they put forward are no more than wild speculation. One can see the reasons for this. The reputation of young scientists, and their promotion prospects, are determined largely by the number of their publications; and because the cutting edge of today's science is so esoteric, it must be difficult to find referees who are fully able to assess the significance of the papers they read. And editors of scientific journals seem ever more anxious to increase their circulation by going for the spectacular and the sensational. So without exception, all the material I have read in the past six years has been insufficiently convincing to make me want to change anything I wrote on scientific matters.

There are, however, a number of subjects covered in the book on which my opinion has shifted somewhat, and I should like to put these on record here.

Chapter 4, Cause and Effect

I remain convinced that the problem of Causation is less complex than many philosophers maintain. The science of the last four centuries has all confirmed the principle of the "Uniformity of Nature". Certainly at the macroscopic level, events are related to each other in accordance with a set of universal rules which science is steadily revealing, rules which often permit us to make exact predictions of future events using only our knowledge of past ones. It is the totality of these rules which constitute the Law of Causation. The Humean view that we can never explain the relationship between events, but can only observe that certain events are always associated with others, is wholly outdated. Hume chose not to encompass the deterministic discoveries of Newton in forming his philosophy, but if he had lived in the twentieth century rather than the eighteenth, and had been confronted with the mass of evidence unearthed by modern Physics, Chemistry and Astronomy, I cannot believe he would have treated the idea of causality so negatively. So I do not wish to change any of the material in Chapter 4, although I would have added another paragraph or two, as I shall explain.

The one aspect of causation which is difficult to understand is its temporal asymmetry. Science shows why events are associated in the way they are, but the links it reveals are not directional. When two events are linked, why do we always call the earlier one the "cause" and the other the "effect"? Why do we believe the first to be responsible for the second, and never the reverse? I argue in Chapter 4 that this impression is wholly subjective, related to the asymmetry of our memories, and our false belief that the past is immutable while the future is still open to manipulation. I am sure this bias can explain the directionality we ascribe to cause and effect, but have recently come to believe that it is just part of a wider asymmetry, and that there may indeed be an objective element which does make later events to some degree dependent on earlier ones, in an irreversible relationship.

I point out on p.61 of the book that most events in themselves are irreversible. The asymmetry arises from the Second Law of Thermodynamics, and in an earlier chapter I show how the Second law can be explained in terms of the expansion of the universe, and by its origin in the "big bang". But adopting the four-dimensional space-time view which I advocate throughout the book, what picture should we form of the expansion, and of the irreversability? At the present time we have no idea how to envisage the big bang itself, and indeed we may never have, but we do understand well the state of the universe a fraction of a second later. In its broad detail, the state of the universe today was already determined by the situation at this very early time. Many of the particles of matter which exist today were already formed, and in our four-dimensional picture we must view these, of course, as world lines emerging from the early universe, and radiating outwards because of the expansion. The illustration below shows just one dimension of space, and time in this view is represented not by distance up the page, as in our simpler illustrations, but by radial distance from the centre.

Electrical theory provides a good (three dimensional) analogy. If we have a charged solid body surrounded by empty space, and if we know the distribution of charge on the surface of this body, the strength and direction of the electric field at every point in the surrounding space is determined by this distribution. Mathematicians call the charge distribution the "boundary conditions" for the electric field, and have developed techniques for calculating the field from its boundary conditions. Now assuming that the universe is finite but boundless, as described in Chapter 2, the only boundary we can admit for space-time is the state it had reached very soon after the big bang, as explained above, and as shown (with two less dimensions) in the above illustration. The behaviour of matter and radiation throughout history is constrained by the boundary conditions imposed at this early instant, in the same way that an electric field is constrained by the charges which generate it. So we have here a demonstration that the state of affairs existing today is a result of that at an earlier time. Perhaps there is some truth in the belief that causes are responsible for their effects, and that the relationship is not symmetrical. The asymmetry which our memory imposes on our interpretation is seen to be just one aspect of a wider intrinsic asymmetry in the world as a whole.

In the essays on "Infinity" and "The Collapse of the Universe" on this website I argue in favour of the universe eventually disappearing in a "big crunch", which in some respects will be a mirror image of the "big bang". If this is accepted, it is fascinating to speculate on whether the big crunch will introduce its own set of boundary conditions, or whether the state of affairs then will still be determined by the big bang restrictions. Both situations are feasible. If a second charged body is introduced into the space around another such body, then the electric field simply adjusts itself to the two sets of constraints. But each body's boundary conditions provide the greatest influence at points near that particular body; we are nearer to the big bang than to the big crunch, and so the world we see is dominated by the big bang. Unfortunately it seems unlikely that we shall ever discover directly any effect originating from this second set of boundary conditions, if it exists; any influence the big crunch may have is too slight to be detected.

Chapter 6, Human Behaviour and Morals

I must admit that I had not read Dawkins' book "The Selfish Gene" before writing this chapter. Now that I have done so I am convinced it is one of the most important books of the twentieth century, and Dawkins one of its most persuasive writers. He maintains that the guiding force behind evolution is not the survival of the species, but of individual genes. He turns on its head the assumed principle that individual organisms use genes to ensure the survival of their characteristics. It is the genes which use organisms to secure their own survival. Dawkins shows clearly that this theory throws much new light on how we should regard the way life has developed on the planet.

Justification for this view is provided when we consider those characteristics which some advanced living things display, and which have obvious survival value if present in the species as a whole, but which are actually disadvantageous to any one individual in the group. Many types of co-operative behaviour come into this category, and it is here that Dawkins' theory shows its real power. A gene which encourages each individual to protect other members of the colony from a predator, even when this involves some risk to the individual's own survival, might well give that colony an advantage over another in which this gene is absent. The old Darwinian criterion suggests this would lead eventually to the dominance of the first colony over the second, but Dawkins shows that this is a fallacy. The mutation which created such a gene must occur originally in just one individual, and the risks that individual might take in confronting predators would constitute a threat to its survival, and the gene would be snuffed out before it could take root in a sufficient number of members of the group to present an advantage.

So how has it come about that we humans do often demonstrate the sort of altruism which the above paragraph shows ought not to have developed by natural selection? The solution offered by Dawkins in Chapter 11 of his book is compelling and reassuring. We have two skills which we share with no other creatures, namely the ability to predict the future consequences of our actions, and the ability to communicate with each other. This enables us to co-operate to behave in ways which we see are mutually beneficial, even when as individuals our instinct is to behave otherwise. A single altruist among a colony whose other members are all selfish will not survive long. But a colony whose members agree among themselves to be helpful to one another has advantage on its side.

So the argument I present on p.89 is rather too simplistic. Dawkins' work shows my error in asserting that evolution is driven by survival of the species rather than the individual. And a little further on, where I write, "A certain degree of altruism becomes an essential part of man's nature", this is a pious hope rather than an explanation. But it is comforting to find that, although some of the arguments in my Chapter 6 are suspect, my conclusions are closely parallel to those reached by Dawkins. The curbing of the elementary instincts of belligerance, acquisition and procreation which I maintain are essential in a civilisation, are described by Dawkins in finer language than mine as a " ... conspiracy of doves", which we can make to work by sitting down together for discussion. After such a discussion, the motivation should exist for members of a colony to behave in socially acceptable ways which can bestow an advantageous stability on the community, but which would give no survival advantage to any individual member, or to his "selfish genes", if not shared by others.

On p.90 I advance the opinion that natural selection is today at work on the human race, at greatly increased speed, because it is using "a different medium for the transmission of characteristics from one generation to the next". Factors are passed on not through a population's genes, "but socially through training and example". This parallels closely the "memes" which Dawkins postulates in his Chapter 11. He gives numerous examples of such memes, customs, crafts, belief structures, music, and indeed any ideas which can exist in the human brain and can pass from person to person either by communication or by imitation. He argues that such ideas will propagate in a manner analogous to the way genes do, that they compete with each other, and that those which proliferate most effectively will survive at the expense of those which are less "catchy".

I do regret, however, that Dawkins concentrates his attention on those types of meme which spread by imitation rather than by conscious transmission from person to person. I maintain that the memes most important for the survival of civilisation are those concerned with decent and moral behaviour, and that imitation does not provide a sufficiently powerful medium of transmission to ensure their survival. Few children are aware of the sacrifices their parents make on their behalf, or of the difficulty of some of their decisions. We seldom realise the wrestling of conscience of those whose actions we admire, or the effort they must make to overcome their own lethargy or their less worthy impulses. No, imitation is not sufficient to ensure the transmission of moral values from one generation to the next. Dawkins has underestimated the importance of education as a medium for the transfer of memes. Indeed, I see danger in his approach. Suggesting that our culture will continue evolving to everyone's advantage as inevitably as our bodies appear to have done, carries the risk of his disciples thinking they need not, or even that they cannot, have any influence on the process. Civilisation is desperately fragile; if too many people believe they have no part to play in its survival, then it is doomed.

Chapter 7, Consciousness

Since I wrote this chapter there have been significant advances in neuro-science. Scanning techniques are being developed that enable brain activity to be observed in ever increasing detail, and some researchers believe the day is not far distant when they will actually be able to observe the workings of consciousness itself. Nor have philosophers been silent on the subject, and I have read a number of papers which attempt to throw some new light on it. But at present I do not feel the need to rewrite any of Chapter 7. It might be helpful, though, if I restate my position in different terms, and perhaps with greater clarity.

The mystery of consciousness is centred on the fact that while humans undoubtedly are conscious, and perhaps some other living things also, to the best of our knowledge everything else in the universe is not. We can usually tell easily whether a person is conscious, and most people would agree that being conscious is the most important fact about them. Everything they do, everything they think, and their very identity as people is related to the fact that they are conscious. And yet a meaningful definition of consciousness proves highly elusive.

Most dictionaries quote something like "a state of awareness" as their principle definition, but this is little more than tautology, since being "aware" is synonymous with being "conscious". Likewise, definitions involving the word "mind" do no more than provide different words for saying the same thing; having an idea "in mind" is simply to be conscious of it. A more substantial definition may use the word "knowing", but something is lacking from definitions of this type. To have knowledge of a fact is to have a record of that fact in the mind, in the same way that a record may exist in a book or in a computer. But whereas books and computers are not aware of the facts they contain, people are.

Indeed there sometimes seems to be confusion between consciousness and intelligence. This must stem from the fact that these are the two features which distinguish humans from inanimate objects, and both involve something happening in the brain. But it is essential to distinguish between the two ideas. There may be disagreement on whether computers should yet be described as "intelligent", but now that the world's greatest chess player has been beaten at his game by a machine, it must be admitted that some progress is being made in the field of AI. But few people would attribute consciousness to even our most sophisticated digital machines. And yet their accomplishments are pushing us ever further into a corner as we seek to distinguish between the mere processing of information, in the mind or in a computer, from the subjective or experiential nature of consciousness. Computers respond to signals from their input devices as we respond to signals from our sense organs. They appear to decide what actions to perform in the light of the nature and content of these signals. They have memories of past events and can store memories of present ones. They can process information inwardly just as we can lie motionless and solve a problem, or picture an image, or plan a stategy. So none of these activities can be said to capture the essence of consciousness.

We are seeking those functions of the human mind which are not displayed by computers, certainly for the foreseeable future, and we can indeed find some of these. Computers do not feel pleasure or pain, they do not experience emotions such as love, hate, fear or envy. Nor do they understand the data they process. And although they may contain images of pictures and sounds, they do not integrate these into a representation of the outside world as we do. So perhaps the essence of consciousness consists of feelings, of emotions, of understanding, and the assembling of our sense data into a wider picture of the world and of ourselves. But we must be careful if we define consiousness simply in terms of those activities which computers cannot demonstrate. Such a definition will ensure that computers, on purely logical grounds, can never be conscious. And it runs the risk of proving at some future time that neither are humans!

The mystery of consciousness seems to deepen as we try to divine its nature by introspection. It is tempting to visualise all our sense data being collected together and relayed to a small screen at the back of the brain, where sits a little man, our consciousness, observing it all from a comfortable seat in the stalls! Even if this were a suitable analogy, however, it would bring us no nearer to an explanation or a definition, for it assumes that this little man himself is conscious. How do we define that?

In fact this picture is nowhere near the truth. Modern brain research shows that when we view even a simple scene, such as a single object against a neutral background, different aspects of this affect many widely separated areas of the brain. The colour has its effect on one area of the visual cortex, the shape on another, and the motion of the object on yet another. If we are studying the object our attention must collect together these widely separated influences. We do not know how this "collecting together" occurs, but it seems likely to be metaphorical, rather than a coming together of real physical signals. Whatever the mechanism, however, it does seem that this attention is the essence of our consciousness. We know from experience that we can think of only one thing at a time; we can give detailed attention to only one of the composite pictures our senses are making available, or if we are in reflective mood, to only one of the many sets of impressions that exist in our memory. It is this close attention that enables us to understand or recognise the particular picture on which we concentrate.

The jostling for attention by ideas in the mind has its most important influence when we need to decide on some course of action, whether immediately or in the future. (This is the process which gives rise to our false belief that we are free agents, and that we can overrule by "free will" the natural processes of the brain, as discussed in Chapter 5.) A particularly powerful example of this motivation occurs when we experience an intense pleasure or pain, which in the former case impels us to behave so that the pleasure is prolonged, and in the latter case so that we escape from the pain. It is clear how evolution has conspired to build into us such potent driving forces, because of their obvious survival value.

Pleasures and pains, along with weaker influences such as emotions and sentiments, are the most forceful reminders to us that we are conscious, and are the characteristics we are most likely to believe will never be displayed by machines. But it is my belief that the pleasure consists solely of the tendency to seek the continuation of the stimulus which causes it, and the pain is nothing other than the compelling tendency to escape.

Despite the significant progress made in recent years in understanding the brain, and despite the disappointing results of our attempts to simulate it with man-made devices, I maintain that we still grossly underestimate the complexity of the brain, and of the thought processes which it can support. It is this immense complexity which raises its deliberations above the threshhold of consciousness.

Chapter 9, Conclusions

Erratum:

The fourth line of p.149 should obviously read:

" ... we rely on there being millions ..."

Bibliography

I would like to add the following two important books to my list of essential reading:

Dawkins, R., The Selfish Gene (OUP, 1976 & 1989)
Price, H., Time's Arrow and Archimedes' Point (OUP, 1996)