VII

MODERN SCIENCE

A. NEED FOR SCEPTICISM ABOUT SCIENCE

B. AIMS AND METHODS OF SCIENCE

C. THE NATURE OF MATHEMATICS

D. PHYSICS, BIOLOGY, PSYCHOLOGY

E. DETERMINACY AND FREEDOM

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A. NEED FOR SCEPTICISM ABOUT SCIENCE

WE must now consider the part which natural science plays in the life of the modern world, and the part which it should play in the better world which we desire to make. I shall first briefly summarize-the whole argument of this and the following chapter, in order to show as clearly as possible how the present subject bears upon the general theme of the book.

Scientific exploration is one of the distinctively human activities. No doubt it is a development of animal curiosity and animal experimentation; but, like art, which also has primitive roots, science is one of the growing points of the human spirit. It is therefore one of the activities which in a properly constituted world-society would be fostered for its own sake, and not merely because of its immense practical utility. In our day there is little danger that science will be neglected, but great danger that it will be prostituted; that as culture becomes more and more debased by industrialism, scientific interest and talent will be directed more and more exclusively toward practical and even purely commercial ends, less and less toward the awakening of human mentality. Already there are plentiful signs that science is becoming a deadening influence. Let us therefore form as clear an idea as possible both of its harmfulness and of its true value.

In what sense can science be a spiritualizing influence? In the first place it is in an obvious sense 'enlightening'. It gives information about tile magnitude and intricacy of the universe, information which cannot but have a salutary effect on the more naive kind of human self-complacency. Secondly, like art, but in a different sphere, it can waken the mind to new and more penetrating ways of experiencing. We may, for instance, be now in the course of learning a more accurate way of conceiving space and time. Man has only very recently begun to explore the world scientifically, but already the whole framework of physical knowledge has been altered, and possibly, if science develops unchecked, the coming centuries will bring profound changes, not merely in man's scientific concepts, but even in his 'common sense' notions and intuitions of the physical world and of his own psychological nature. Finally, the spirit of scientific detachment, of respect for the facts, no matter what the conclusions to which they point, can be a truly spiritual discipline, and can for some minds open the way to a dispassionate yet fervent worship, not of a God conceived in man's image, but of the inconceivable, and in a sense inhuman, reality which everywhere confronts the experiencing mind. I shall have more to say on this subject when I discuss religion.

The dangers of science are as formidable as its promise is beneficent. Ours is said to be a scientific age. We have far more knowledge of the scientific kind than earlier peoples ever had, and owing to the effects of science our civilization is already very different from all earlier civilizations. In every country that has come under the influence of science men and women live in ways that were formerly impossible. Not only do they travel in trains, motor-cars and aeroplanes, speak to one another across continents, and make use of innumerable products of factories and laboratories, but also, through the influence of science, they are coming to have a new view of the world. Not only are the scientists themselves deeply influenced, but also the minds of ordinary men and women are increasingly dominated by the second-hand scientific ideas which they pick up from newspapers, books, wireless and the cinema.

Every year the part that science plays in the world is greater than in the previous year. Scientists are becoming more and more important as a class; and some day they may possibly take charge of the government of the whole world, and control it far more effectively, for good or ill, than politicians can ever do.

Many persons are quite unable to conceive that there should be any weakness or danger whatever in such a triumphantly successful thing as science. I have already, in Chapter I, suggested that they are mistaken. I shall presently try to show- in more detail that, though science is one of the most splendid, and life-giving, and world-building, of all our activities, it is also harmful, not merely because we use its inventions to destroy one another or enslave one another, but also because it may confuse our minds.

Every age has its own peculiar mental climate, or fashion of thought, and ours is scientific. The prevailing climate of our time affects us all to some extent; but especially it affects those brilliant, but perhaps sometimes too confident persons, who are regarded by the man in the street as the advance guard of progress. It is very difficult for the ordinary more or less intelligent man, who is at pains to keep abreast of his period, to realize that the prevailing fashions may not be entirely sane. Unwittingly he is inclined to favour the fashionable set of arguments and beliefs and be suspicious of any less fashionable set. Though he may very well be far more open-minded in some respects than those who are definitely 'behind the times', yet his mind tends to be partly closed on one side. He is not quite open-minded enough, or clear-headed enough, or earnest enough in his thinking, to see the weak spots in fashionable ideas.

In our age all normal persons have at least some scientific interest. Like apes and monkeys, human beings are by nature inquisitive animals, and meddlesome or experimenting animals. They have also some capacity for understanding. If they are to attain complete well-being, they must exercise these capacities. To-day, the way in which they exercise them most easily is by means of science. Most of us, even those who have no special bent for scientific work, are deeply influenced by scientific ideals of thought.

This is entirely to the good, so long as it does not close our minds to experiences which science does not consider. Science is a highly developed activity which is favoured by the circumstances of our age, and it is well for us to take advantage of our opportunity and be scientists so far as we can. We cannot all be expert scientists, any more than we can all be creative artists or philosophers or gardeners or postmen. But just as we all need to be artists and philosophers in some degree, so we all need to be scientists. On the other hand, since science is to-day more fashionable than art or philosophy, there is more danger that we may become blindly scientific than that we may become blindly artistic or blindly philosophical.

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B. AIMS AND METHODS OF SCIENCE

I shall now try to describe as clearly as I can the essential characteristics of modern natural science, in order that, in the following chapter, I may give a more detailed estimate of its value.

It may be well to begin by pointing out that the word 'science' has two meanings. In one sense every kind of intellectual inquiry may be said to be 'scientific' if it is unprejudiced and thorough; every kind of knowledge may be said to be 'science' if it has not been falsified by the demands of emotional satisfaction. In this sense our age is suffering not from too much but from too little 'science'. Only those who believe that intellectual activity is essentially deceptive can object to 'science' in this wider sense of the word.

But the ordinary meaning of 'science' in our day is more restricted. By 'science' we mean Modem Natural Science, a movement of thought which began to have importance in the Renaissance, and is now at its height. In this sense 'science' consists of the system of knowledge which modern scientists have constructed, and of the method, the process of inquiry, by which they make their discoveries.

The system of knowledge that is called science is always changing. It keeps on spreading over new fields, becoming more exact in detail and more systematic as a whole. Scientists are ever making new discoveries, establishing new theories, reorganizing old theories. Matters which formerly lay beyond the reach of scientific inquiry are one by one tackled and scientifically understood.

The method of inquiry, which is also called science, or more accurately 'Scientific Method', does not change. It is differently applied at different times and in different fields of research, but it remains essentially the same method always and everywhere. It varies only in being adapted now to one kind of scientific field, now to another, or in being now thoroughly and now inefficiently carried out. Of course, the observation of worms and jellyfish is a very different undertaking from the observation of stars, or again of human beings, or of electric currents. Each field of observation demands a special technique. Also, the technique of science to-day, in all its fields, is much more complicated and exact than the technique of the earliest true scientists. But in every age and every field of research the general method of science is identical. It is simply the method of observing events as carefully as possible and describing them as accurately and simply as possible, either by means of principles and formulae invented for the occasion, or preferably by principles and formulae already found useful on other occasions. This process of description often takes the form of explaining the perceived in terms of the hypothetical unperceived; but always scientific explanation is but an extended description, given in terms of concepts all of which are derived originally from our perception of the physical world.

When a scientist's curiosity is aroused by some kind of event in the physical world, he sets about observing, and if possible experimenting, so as to gather facts that bear upon his problem. He uses his senses. He looks, listens, touches, smells, tastes. Whenever possible, he uses sight rather than any other sense, because sight gives him much more varied and detailed information than the other senses; and especially because by careful seeing, and comparison with standard visible scales, he can very accurately measure the size, shape and position of things. But though he uses chiefly sight, he is apt to think very largely also in terms of the experience of touch, and of the resistance of physical objects to his effort.

Often the scientist devises instruments, such as micro- scopes, telescopes, balances, measuring rods, clocks, which will give his senses additional experiences, and his intelligence further data to interpret. By one means or another he tries to approach the puzzling kind of event from as many directions as possible, and also to collect as many examples of it as seem necessary to show him just what the essential common characters in all examples really are.

When he has thus gathered a mass of facts, he tries to invent principles or laws or mathematical formulae which will describe them as accurately as possible and also as simply as possible. More precisely he sets out to describe, either in words or in mathematical symbols, principles which do actually characterize or hold good of, the observed facts.

Sometimes he makes use of principles with which he is already familiar. He says, 'at bottom this is just a special case of such and such a well-known law'. Sometimes, however, the facts are so odd that he cannot connect them with any familiar principle. He must then either discover a new principle or re-state an old one more accurately, to fit the new facts.

If possible, he describes the facts in terms of the principles which apply over the widest field, and seem to underlie many of the special principles of particular fields. The principles which have actually proved most useful, and have seemed most fundamental, are those which are discovered in the study of moving objects, and their interactions with one another. Of course, the subtle laws of modern physics describe very queer objects and very queer movements, and indeed a very queer space and time. But in essence they are simply a development of common-sense experience of moving objects, seen and felt.

When the scientist thinks he has found the principle which is the essential principle in all his facts, he works out logically or mathematically some of its possible consequences in various directions, and tries to confirm his predictions by fresh observations and experiments. If he still finds no facts which are inconsistent with his principle, he accepts it as a 'law of nature'. By this he means that, whether his description of his principle is given in English or French or Chinese or mathematical symbols, and whether his measurements are made in inches or centimetres, miles or kilometres, pounds or kilograms, degrees Fahrenheit or degrees Centigrade, it is in fact a true description of the actual order or pattern in which events occur.

If some day he comes upon a kind of event which seems to violate his law, either he has to show that this kind of event is not, after all, really relevant to his law; or if it is relevant, he has to see the underlying principle of his law more precisely, and re-state it in such a way as to cover the new kind of event.

Let us consider one outstanding example. Early scientists discovered the principle which holds good of falling bodies near the earth. They described mathematically the rate at which falling bodies increase their speed every second. Newton discovered that the same principle, seen more broadly and accurately, was true of the movements of the planets. In our age, however, certain facts cropped up which suggested that the law of gravity had not, after all, been quite truly formulated. For instance, the planet Mercury did not behave precisely as was expected. Einstein and others, using a mathematical technique which had not hitherto served any practical purpose, described the principle behind the old law much more accurately, so that it was seen to include under its rule not only the awkward facts, but also vast new fields.

It is extremely important to realize that the scientist works by the method of abstraction. All understanding consists in discovering some kind of order in a mass of facts which appear at first chaotic. If we are looking for order, we have first to distinguish different characters within the chaos, and to observe the relations which these characters have to one another. Then we attend specially to those characters or classes of characters which either happen to be of interest to us, or seem to be the essential characters for the understanding of the whole matter. This is the essence of the method of abstraction. It consists of drawing something away from something else which is left behind. When we abstract we attend to and think about certain characters within a complex mass of characters, and we ignore the rest.

The pioneers of modern science were faced with the blend of confusion and order which we all meet in our ordinary perception of the physical world. They seized upon such tissues of order as were given in perception, and sought to extend them by relevant observations, experiments, and generalizations. Inevitably they attended to the more promising, more readily intelligible aspects of the physical world, and ignored the rest. Desiring to understand precisely and unambiguously, they sought wherever possible to gather data which could be measured, and they developed a mathematical technique for expressing the results of their measurements in comprehensive formulae. Little by little this process led them to concentrate chiefly upon movements, great and small, and to work out those very general dynamical concepts, such as energy, resistance, mass, momentum, which have played so great a part in physical science up to our own day. Though the advancement of science has proceeded by the inclusion of ever wider fields within the scope of research, it has also, in respect of its explanatory principles, involved an ever more rigorous exclusion of those aspects of the perceived world which were not amenable to mechanical and mathematical interpretation. This process gave us in the nineteenth century the conception of a universe composed of microscopic 'billiard balls' charged with electro-magnetic energy, but has since advanced even farther in abstraction. To-day the physicist 'has abandoned even this much of concrete perceived reality, and claims only to describe the mathematical relations of 'somethings' the qualitative nature of which lies entirely beyond his scope.

Now the mathematical aspect of the objective world really is an aspect of it, and a very significant aspect of it. But qualitatively it is a very meagre aspect. Mathematics is extremely abstract. A physics which has excluded all but the mathematics of physical reality is in no position to afford the basic principles for explaining all things in heaven and earth. Let us spend a few moments in considering what the activity of mathematics really is.

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C. THE NATURE OF MATHEMATICS

Mathematical philosophers are far from agreeing about the nature of mathematics. Two important schools at least would reject the following account of the matter. But for what it is worth I shall sketch that view which accords with my whole picture of man-in-the-universe.

The mathematician, then, like the rest of us, is faced by the huge mass of characters which make up the world, so far as it is presented to man. But, as a mathematician, he is interested most in one great set of these characters, one aspect of the world, namely the mathematical aspect, or the ways in which things, or characteristics of any sort, can be counted or computed.

What, at bottom, is counting? What are the 'numbers' by means of which we count? Ages ago men noticed that there was a certain identical character in all groups of the kind which we now call 'couples'. Whether the parts of the couple are hands, or stones, or stars, or men, or days, or pains, or thoughts, whether the parts are of the same kind or of different kinds (say a man and a woman, or a man and a day), always the couple has a certain character, in virtue of which it differs from all single things and triplets. And triplets themselves have all a certain character in virtue of which they differ from all quadruplets, and so on.

Men noticed also that if a 'single thing' was added to another 'single thing', there was a 'couple'; and if another thing was added to the 'couple', there was a 'triplet', and so on. Not only did they see that this always did happen whenever they added anything to a group, but also they saw that it must be so, because of the inherent nature of singles and couples, and so on; because a couple actually was one less than a triplet, and so on. And because of this inherent nature of groups, they were able to work out many very complicated mathematical laws.

They also invented such things as 'imaginary numbers', which are not characters of any possible groups. Thus √-2 is an imaginary number, since no number whatever multiplied by itself .can give a minus quantity. Imaginary numbers seem at first to make nonsense of the view that mathematics deals only with the actual characters of groups. But there is, perhaps, a key to such puzzles. The three marks √-2 do not really mean any one character at all. They mean three distinct things, namely 'two' (the character of any couple whatever), 'minus' (the operation of subtracting or taking away), and 'square root' (the operation of finding what number multiplied by itself will give a required number). The two marks √4 mean a real number, but the three marks √-2 do not. All the same they can be used in the game of mathematics as though they did in combination mean a real number. Similarly with the very many other paradoxical mathematical symbols, and formulae; if they are taken as wholes, they cannot mean any real character or possible operation, yet they may be analysed into elements each of which does mean a real character or a possible operation.

We may significantly compare mathematics with a highly artificial game such as chess. No doubt chess was originally derive a from the actual nature of contemporary warfare. Its pieces were stylized and simplified warriors, its rules and moves stylized and simplified martial operations. One striking difference there is between chess and mathematics. Games of chess cannot be used for finding out anything important about the conduct of modern war; games of mathematics can be used for finding out much of importance for the control of the physical world. This difference would seem to be due to the fact that the numerability of things remains always the same, but the operations of war have changed. Thus, though mathematics has indeed been very much 'stylized', and has proliferated into many forms and conventions which seem to have no application to the physical world, it has also produced a number of systems which do as a matter of fact continue to have such application.

So long as mathematics deals with distinct individuals that can be numbered, it can operate without paradox. But when it attempts to deal with continuities, such as time or space, which seem not to be composed of atomic parts, mathematics becomes very paradoxical. It has to apply principles derived from one kind of objective experience (namely experience of distinct individuals) to another kind of objective experience (namely experience of continuous quantity), and this it cannot do without paradox. It has to pretend that continuity is composed of an infinite number of distinct and atomic units; and to deal with this infinity it has to invent many paradoxical concepts. But always, however metaphorical his thought, the mathematician thinks in terms of numerability such as he originally experienced in contrasting any group with a greater or smaller group.

Calculating by means of the laws of number, scientists are able to predict confidently what would happen in all sorts of situations in which number is concerned. They are able to deal mathematically not only with separate 'things' but (though often paradoxically) with continuous quantities of any of the measurable characteristics that make up the perceived universe, such as length in space, duration in time, and all the characters that can be measured by means of length and duration, such as weight and pressure.

Mathematicians find their mathematical activity intensely satisfying, since it fulfils so well their capacity for grasping order or system. They find in the intricacy and exactness of the science of pure number, or of the 'numerability' of things, a severe beauty, like the beauty of certain kinds of music. Here mathematics seems to be related to the aesthetic delight in form. Partly through the sheer fascination of mathematics, partly through the fact that it applies to hosts of characteristics of the physical world, and is extremely useful for the control of physical events, men have sometimes been inclined to think that the mathematical aspect of the world was in some way the most real and fundamental thing about it, and that everything else could be explained by mathematics. Thus the philosopher Pythagoras said that everything was number.

Such a view shows very clearly the danger of all abstraction, namely that in fixing attention on one kind of character in the world, we may come to think that nothing else matters, or that nothing else is real, or that, at any rate, everything can be explained by the principles or laws of one particular study, whether of mathematics, or of physics, or of psychology. But it should be obvious that, for instance, the world cannot simply consist of number, since, for there to be number, there must be 'somethings' other than number, to be numbered or numerous. Number implies numerous or numerable instances of some quality or other.

But though the method of abstraction has its danger, it is very necessary. Indeed, all our intellectual knowledge of the world has been reached in this way, namely by attending to, and studying, certain characters and relations of character, and ignoring others. Human minds cannot attend to everything at once. So long as we remember that we are abstracting, and do not imagine that what we are studying is all that matters, no harm is done. Of course, if we want to know our world as truly as possible, we must try to see the relations of all our different kinds of abstract knowledge, so as to form a system of knowledge which takes everything into account. This is the task of philosophy.

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D. PHYSICS, BIOLOGY, PSYCHOLOGY

Since the days when men first dared to doubt the accepted theories about physical nature, scientists have built up, generation by generation, a number of great sciences, great systems of knowledge about different kinds of events and facts. As time passes, these great systems become more detailed and accurate and also more closely connected with one another. The ideal of the scientists is to unite the many sciences together in one all-embracing science. But though they have made much progress in this enterprise, they have still very far to go. In our day there are many distinct sciences. Some are very closely connected in their fundamental nature, such as physics, chemistry, astronomy; some are much less thoroughly connected, such as physics and biology, physics and psychology.

Physics is concerned with all the seemingly most fundamental characteristics of the physical universe, such as gravity and electro-magnetism, every kind of movement, and even space and time themselves. Whether or not these characters really are fundamental, or are merely aspects of something much deeper and much more all-embracing, they certainly are the most fundamental characters from the scientific point of view. Astronomy deals with the physical laws of the solar system, the stars, the nebulae, the galaxies, and with the physical structure of the cosmos as a whole. Chemistry studies the different kinds of matter, and so far as possible reduces their differences to fundamental physical characters. Geology studies the structure and history of the earth, seeking to interpret its data by means of physics. It also takes note of the fossilized remains of living things, thereby connecting itself with biology.

Biology includes many sciences, such as physiology and zoology, all of which are concerned with living things, their general nature, their varieties, their structure and behaviour. In some respects biology has many connexions with chemistry and physics. Very many events in living bodies can be described by chemical laws. But whether all such events will ever be so described is at present uncertain. Some biologists insist that in the behaviour of a living thing as a whole, and in its form and origin, there is a purposefulness which cannot conceivably be described in terms of principles which are purely mechanical. Others are equally confident that all such 'teleology' is illusory.

Psychology is concerned with the ways in which living things, and especially human beings, behave consciously; or with the description of their awareness and their striving. The kind of events which psychology studies cannot conceivably be completely described purely by the physical laws of moving bodies. Thinkings and desirings, admirations and hopes, are a different sort of event from failings, explosions and electric currents.

If we consider the great company of sciences, we see that they fall into three classes, namely: those which deal with 'dead matter', and describe its behaviour by purely mechanical laws; those which deal with living things, regarded externally, but regarded sometimes as purposive, and not as purely mechanical; and those which study and make use of man's experience of his own mental life, of his knowing and feeling and striving.

If the sciences are to be united as one great science, they must be shown to be all based on the same fundamental principles, or concepts, or laws. Either physics must swallow biology and psychology, or psychology must swallow biology and physics; or we must work out some science more fundamental and more comprehensive than either physics or psychology.

If physics is to triumph, the seemingly purposive behaviour of living things must be explained away in terms of physical mechanism.

The principle of mechanism may be roughly defined as that according to which, given event A, then event B will follow, whatever its consequences. This is contrasted with the principle of teleology, or purposiveness, according to which, given event A, there will follow a train of events conducive to an end Z. Teleology does not necessarily include any reference to consciousness. Mechanism is not necessarily confined to the physical. Mental processes, for instance, might be purely mechanical.

In the fields of physical science mechanism has proved an extremely useful principle, teleology has been abandoned. Indeed, so accustomed have we become to the idea of mechanism that we seem to discover in it a logical necessity which we do not find in teleology. But this feeling of necessity in the connexion of physical cause and effect is illusory. All the laws of physics are based upon inductive observation. There is no demonstrable necessity in virtue of which an unsupported stone must fall; but we are so used to observing such events, that we confidently expect matters to turn out in the familiar manner.

Though mechanism has, till recently, been unquestioned in physics, and is still making headway in the biological sciences, psychology is as yet very far from being reduced to physical mechanism. Of course, as was noted in an earlier chapter, it might turn out that all mental events were related to and dependent upon, certain physical events, say in the brain; and therefore that consciousness itself was entirely ineffective. This is far from being proved; but even if it were, our mental life itself would not be describable in actual physical terms.

If psychology is to triumph over the other sciences, both biology and physics must be shown to be really dealing with the physical manifestations of striving minds. In the case of physics, the minds would have to be the minds of electrons and protons, or of whatever are the simplest physical things. All physical events, including volcanic eruptions and the movements of stars, would be the result of the massed strivings of innumerable 'minute' minds; save where they could be shown to be controlled by 'larger' minds, such as our own, or, say, the minds of galaxies or stars, or the mind of the cosmos as a whole. But even if this were shown to be the case, the physical aspects of minds would not be describable in psychological terms.

At present psychology is obviously incapable of swallowing physics, and to the clear thinker physics seems quite as incapable of swallowing psychology. Each remains obstinately outside the other.

But physics is a greedy science, and having already almost succeeded in swallowing chemistry, it looks hungrily toward biology, and toward psychology also. More accurately speaking, scientists have generally been more inclined to explain life and mind in terms of physical mechanism than to explain physics as the psychology of atoms or electrons, or of God's imagination.

It is easy to see how scientists have come to have so strong a faith in physical mechanism. The pioneers of modern science were not only inquisitive and intelligent, but apt with their hands. They enjoyed devising experiments and instruments. They did not feel bored when they were manipulating weights, pulleys, lenses, scalpels. Though many of them were interested in theology and philosophy, all of them were gifted also with a natural interest in tangible and visible things. Consequently they were favourably disposed toward explanations in terms of the tangible and the visible.

It so happened that there were vast fields of exploration waiting to be opened up by people who were inclined to make practical experiments, and intelligent and patient enough to observe the results accurately. The experimenters met with surprising success. They found themselves able to make matters look intelligible and precise which had seemed erratic and more or less miraculous.

As time passed, and the sciences became more and more detailed, and the idea of mechanism became more and more useful, many scientists began to feel that in describing the mechanical principles of things they were giving a complete account of the nature of things, and a complete explanation of their behaviour. It came to seem unnecessary and fantastic to explain events in terms of God's will, or human purpose, or the striving of physical things themselves. Moreover, if you thought of things behaving mechanically and in definite ways according to their nature, you could make them serve your purposes. You could make steam engines and electric motors, you could perform surgical operations, and so on. The other idea was too vague to be of any use. Thus as our modem machine-served world developed, men became ever more impressed by mechanical explanations; ever more convinced that, to explain any mysterious set of facts, it was only necessary to show their relation to some familiar mechanical system; and that, if no such relation could be found, the mysterious facts must be unimportant or even unreal.

Thus scientists, and the ever-increasing host of people who were deeply impressed by science, came to distinguish between the characters which, they said, really belonged to things, and those which merely seemed to belong to things, but were in fact mere figments of our minds. The real characters were those which were supposed to be mechanically effective, such as shape, size, movement, hardness. The unreal ones were those which seemed to play no direct part in the mechanical system of the world. These included the 'secondary qualities' (such as colour and sound), the beauty and ugliness of natural objects and works of art, the pleasantness and unpleasantness of all our activities, the rightness of certain human actions and the wrongness of others. The mysterious, 'inner life' of a mind, with all its desirings and fearings, its passions, its acts of will, its insight into beauty and rightness and rationality, were held to be somehow caused in us by underlying mechanical events. Thus if a man believed that he moved his limbs by 'an act of will', he was mistaken. If he believed that they moved because he desired them to move in defence of his beloved, or to make money, or to go to church, he was mistaken.. Their movement was wholly due to intricate mechanical causes whose nature was physical.

The study of mental events was allowed to belong to psychology. But it was assumed that if the very backward science of psychology could do its work properly, it would somehow show that all its laws were at bottom physiological laws. And these, it was thought, must be at bottom merely special cases of the universal mechanical laws of physics.

Unfortunately psychology remained backward. The study of the 'inner life' of a mind was very much more difficult than the study of moving objects, chemical combinations, and so on. Even to-day, in spite of the widespread interest in psychology, and the really important discoveries that have been made, our knowledge of ourselves and of the nature of mind is extremely vague and uncertain. The Newton of psychology has yet to be born.

It is true that psychology has at last made a beginning. It can roughly classify the kinds of mental actions, and it can show that some are much simpler than others. It can also describe some of the differences between a healthy mind and an unhealthy mind, and tell us, up to a point, what is necessary for mental health. In co-operation with physiology, it can tell us a good deal about the ways in which mental life is influenced by bodily life, and the reverse. But how the one is related to the other, and what it is that experiences, and what the real natures of the most complicated and highly developed mental activities are, it cannot say. All it can do is to try to explain the more complicated in terms of the simpler, and these again in terms of the simpler still. Some psychologists expect to explain everything in terms of physiology; and physiology they would hand over to chemistry and physics. But this kind of explanation has to ignore, as it descends from stage to stage, everything which is distinctive of the higher stage.

At present no one knows the true solution of the great problem of the relation of the physical, the biological and psychological sciences. It is something, at any rate, to see clearly that there is a problem, and to be on our guard against false solutions of it.

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E. DETERMINACY AND FREEDOM

Some scientists have suggested that, when the simple physical units, say atoms or electrons, come together into certain very complicated patterns or organizations, an organism thus formed generates new powers, of which its parts, as loose units, had no trace whatever. Thus, they say, arises the unconscious purposefulness of simple living organisms, and on a still higher plane the consciousness of the more developed organisms, such as ourselves. But how a mere pattern can have such miraculous powers they cannot explain.

Others suppose that even in the simple physical units there are, as a matter of fact, latent capacities which, when the units are not organized together as living things, cannot manifest themselves. Therefore they cannot be detected by our purely physical experiments. Similarly, these thinkers would say, human beings brought up in isolation from one another would never manifest the complex social ways of behaviour which we know in the actual world of men in society; but nevertheless there would be contained in them all the necessary capacities for such behaviour. It is insisted that if we could discover the whole nature of the seemingly merely physical units, we should be able to predict the behaviour of any kind of system made up of such units, even of living organisms.

Others, again, are convinced that modern physics has discovered, even in the known physical behaviour of the physical units themselves, a fundamental arbitrariness. They claim, not merely that we are too ignorant to be able to predict the movements of a particular electron, but that its movements are absolutely unsystematic, unrelated to other facts, and therefore in their own nature unpredictable.

If this view is correct, all ordinary physical laws of the behaviour of matter in bulk describe, not how matter must of necessity behave, but how the myriad arbitrary actions of the minute units will probably turn out in the long run. They might conceivably turn out very differently. A kettle of water on the fire might freeze instead of boiling. But there is a very great probability that on any.. particular occasion it will boil and not freeze. But what is probability? Is it anything more than our own irrational tendency to expect things to behave as they have formerly behaved? Or again is it an objective fact which determines our expectation, namely an actual though obscure connexion between objective events of certain types?

Some scientists are confident that this view that the physical is indeterminate is confused and false. Those who hold it, they say, mistake the limitation and uncertainty of our scientific method for an uncertainty or arbitrariness in the actual physical world. They point out that though we may not be able to predict when an electron will jump, or where precisely it is at a given moment, we know that, sooner or later, jump it will, and that at a given moment it will be, at any rate in some sense, somewhere within a very narrow field. Had we a much more intimate knowledge of electrons, we should see (so they tell us) that the seemingly arbitrary behaviour of each electron is the exact expression of its nature in its particular environment.

To many of us this view somehow 'tastes' more credible than the other. Perhaps in the last analysis the two accounts will turn out to be merely different ways of saying the same thing. We cannot help noting, however, that there may be kinds of facts about electrons and their environments which are not physical facts at all. Conceivably, for instance, the electron's mysterious jumps are partly the result of its own mental nature, or of the influence exerted on it by hidden mental characters of the universe as a whole. Even if this were the case, however, its jumps might quite well turn out to be systematic, or 'determinate', and not arbitrary.

Since the dispute between the determinists and the indeterminists in physics seems to have some relation to the 'free will' controversy, it is bound to be influenced by powerful though often unwitting emotional dispositions. Many people are outraged by the thought that their actions are determinate expressions of a personality which is itself the determinate outcome of a vast system of causes. They prefer to think of themselves as unique, uncaused, and gifted with the power of arbitrary choice. Any physical theory which seems to lend support to such a view is therefore agreeable to them. For similar reasons those who are strongly moral or moralistic welcome every theory which is opposed to the advance of determinism in science. If moral choice is determined, they say, all that seemed most precious in human nature is illusory.

Now I myself am not at all distressed by the possibility that my acts are not arbitrary but determinate, and in theory predictable. I am content that my choice should be in every case an expression of the interaction of my nature and the environment; and that my nature itself should be an expression of an infinite series of past ancestral natures and past environments. I recognize that when, in youth, I was outraged by this possibility, I was moved only by a rather puerile self-pride; and that in my former insistence on 'free moral choice' I was actuated largely by an unlovely desire to blame and punish others and myself. Nor does the belief in determinism make me any less capable of 'moral effort'. For determinism does not imply that human will is ineffective but only that it is a determinate expression of past causes. Within limits I am free to do as I will. My choice is effective; but how I shall choose is an expression of my extant nature, and possibly this is determinate. I did not arbitrarily make myself. The insistence on arbitrary free will seems after all rather smug, and even impious. One of the most salutary effects of science, I should say, has been this gradual schooling of our minds to overcome the self-complacent prejudice in favour of arbitrary choice. In this respect at least science has, I believe, had a spiritualizing effect. In giving man a sense of his indissoluble unity with the rest of the cosmos; and persuading him to be glad of it, the influence of science has been almost literally religious, binding, harmonizing.

But there is another side to the matter. Determinism in the sphere of physics, and in the sphere of psychology, rests entirely on observation and induction. There is no reason whatever why the universe must be systematic through and through. Up to a point it has so far revealed itself as systematic, but it may break all our scientific laws to-morrow. The sun may assume the features of an old lady, and go pirouetting through the sky, winking and smiling. Men may sprout wings. The starry heaven may roll away and reveal Jehovah among his angels. All things are possible. But all things are not equally desirable. And for my part, at any rate, I find the determinate but mightily pregnant universe which the sciences are beginning tentatively to explore more desirable than an indeterminate one.

There is yet another point. Determinism does not deny spontaneity. Even in the sphere of physics, and even if the truth is that the movements of electrons are determinate, yet their movements are in part spontaneous. If all electrons were merely passive, the whole universe would be passive, which clearly it is not. Each electron makes its own spontaneous contribution to the activity of the cosmos, though it is also influenced by others. Even if its actions are determinate, they are its actions, free expressions of its nature. A man is in the same case. His choice is absolutely spontaneous. In every choice he creatively contributes to the universe. What more of freedom is desirable? What matter if, within limits, we can work out inductive laws by which to predict how he probably will choose? Our laws do not constrain him. They are laws describing only how he and others are, in fact, observed to behave. Thus did he behave in the past: probably he will behave thus in the future. Our predictions are true of him only so long as he remains what he is. If by some sudden spiritual leap he rises to a higher nature and breaks some of our laws, we must make fresh observations and seek to discover more comprehensive laws. If even that creative leap itself is determinate, an expression of hitherto undiscoverable powers in him, of powers focused in him by age-long history and evolution, what matter? So long as my striving is allowed to be an actual effective influence in the world, what matter though it in turn is a product of the past world and the past age? There is no reason whatever to doubt that when we are aware of striving we are aware of exerting our own dynamic nature, and of taking effect on our environment.

Chapter 8

Chapter 6

Waking World Contents