§ 1. Science and common sense
It may seem absurd to talk about the philosophers' world. Why cannot philosophers be like other people and content themselves with the world revealed to science and common sense? There are many reasons other than natural perversity. One reason is that common sense and science so quickly get out of step.
To common sense the world is in the main made up of solid bodies. These bodies are coloured in various ways; they are soft and hard, hot and cold; and they have at any moment a definite size and shape and weight. It is true that both the size and the shape may look different from different distances and different points of view, and even the weight may feel different if we hold the thing weighed in different hands. But we can get over these difficulties by simple processes of measurement. By measuring a body we can find out what we take to be its real size and shape and weight; and these we oppose to its apparent size and shape and weight. We can even understand by elementary geometry why a penny which is really round must look elliptical when seen from a certain angle and located in a plane other than that in which it is.
The real characteristics determined by measurement may be called primary qualities. In the case of colours we cannot make this difference between the real colour and the colour as it appears, nor can we determine what the real colour is by measuring it. Characteristics that cannot be determined by measurement may be called secondary qualities; but to common sense they are none the less real qualities of bodies; and here the real quality may be said to coincide with the apparent quality. Grass does not merely look green: it is green. We may even believe that grass not merely looks beautiful but is beautiful. Yet beauty is a different kind of quality from greenness: it seems to depend on a combination of qualities like colour and shape, and it may be called a tertiary quality.
Science, unlike common sense, is concerned only with what can be measured: the world of science is a world of primary qualities alone. This at least is—or used to be—the ideal of science and the secret of its success, although the ideal may be fully attained only by the more developed sciences, notably by physics. Hence it is not surprising if scientists, at any rate as they begin to think philosophically, tend to dismiss secondary, and still more tertiary, qualities as unreal. More precisely, greenness is not for them an intrinsic quality of the grass itself: it arises only when certain light waves are focussed on the retina of a normal human eye. These light waves can themselves be measured, but it would be absurd to say that invisible light waves are green; and the measurement of the waves which cause grass to look green is not a measurement of the green colour itself, even if it may be correlated with differences that can be seen.
Once embarked on this course of measurement science gets more and more out of hand, so far as common sense is concerned. Our comfortable solid bodies are found to be composed mainly of empty space; for they are divided into molecules, and the molecules are divided into atoms, and every atom is a solar system in itself. This has led Eddington into speaking of his two tables—his common-sense table and his scientific table; and it suggests that the world of science is a different world from the world of common sense. Again, even on Newtonian principles, weight is found not to be a property of a body itself: it depends on the relation of the body to other bodies. For Einstein a body does not even have a definite fixed size and shape: what common sense calls its real shape and size differ, and must within certain limits differ, according to the position and velocity of the instrument by which its size and shape are measured—rather like the way in which, on a common-sense level, the seeming size and shape differ, and must differ, according to the position of the observer. The primary qualities of objects have ceased to be absolute and have become relative. All our ordinary concepts of shape, size, motion, energy, and even of space and time, have to be modified or exchanged for others. The talk about atoms as solar systems may itself already be out of date. No wonder we are left breathless: we seem to be plunged headlong into a different world.
But this is not the worst. We ordinarily assume, in spite of difficulties, that we are directly and immediately aware of bodies and their qualities. All our knowledge of the external world is built up on this supposition. Even a scientist, we may imagine, regards his measuring instruments more or less in the same way as we regard tables and chairs. All his measurements must in the end be based on what he can see and touch. How could he use a spectroscope unless he were immediately aware of the colours on its surface? Hence his account of what he measures seems to be applied less austerely to his own measuring instruments. But even if this need cause no qualm, a further fact emerges which is truly staggering. As the process of ever exacter measurement goes on, we discover that direct awareness of objects is a myth. When, as we suppose, we see directly the colour and shape of grass, what is really happening is something like this. Certain rays of light are reflected back from a surface to our eye, and this sets up in our nervous system a process which ultimately reaches the brain; and then we see a coloured shape. Seeing, that is to say, is a final effect in a very elaborate chain of causal events. But an effect need not be like its cause, and there seems to be no reason for supposing that the coloured shape we see bears the slightest resemblance to its original cause. We have to abandon our belief in the direct perception of bodies, and we begin to wonder whether we have any contact with reality at all.
It may be replied that the conclusions of science cannot be thus used to discredit the premises from which they are derived. Perhaps not. But we ought at least to note that this is precisely what seems to happen, and the problem cries out for a solution. It should not be solved, as it sometimes is, by a simple appeal to faith in science. We proceed strangely if we first of all reject faith in the name of science and then go on to uphold science in the name of faith.
§ 2. Materialism
Philosophers cannot but be dissatisfied when they are left with two separate worlds on their hands—the world of common sense and the world of science. They dislike this bifurcation and the contradictions to which it apparently gives rise—as sober men they have a rooted objection to seeing double. The simplest way of escaping from this is to say that one of the two worlds is illusory or unreal, or at least that it is derivative and subjective. One method of maintaining this is to adopt the philosophy of materialism.
The materialist accepts the world of science—the world of primary qualities—as the real world. Matter is the primary reality. It exists in itself independently of our perceiving and thinking; and it is the source of our sensations, ideas, thoughts, and indeed of mind itself. Mind is thus secondary or derivative or, as is sometimes said, epiphenomenal. In extremer language, the material world is the only reality.
But what then is the material world? For the older materialist the answer was simple. The world was made up of little bodies or particles acting and reacting on one another like billiard balls. It was in short a kind of machine, or mechanism, of which it was possible to construct, or at least to picture, a model in miniature. There was no nonsense or mystery about this straightforward engineer's world, and its laws were completely knowable. Many of its laws were already known, and it only remained to discover more and more of them by the scientific methods which had already justified themselves by success.
This old-fashioned, simple-minded conception of the material world has now gone by the board. The little bodies or particles have been replaced by electrons, which are not particles at ail. Causal laws are replaced by statements of statistical averages. All the conceptions which had seemed so fixed and firm, including those of time and space, are transmuted and transmogrified into very different conceptions, for which we can construct no miniature models; and perhaps no one knows how this process is going to end. We cannot be certain that our present scientific conceptions may not in turn be transmuted into something else. Hence we cannot say that we have knowledge of the world as it really is; and some scientific thinkers propound the paradox that although we know our own measurements, we have no idea of what they are supposed to measure.
Those who object to materialism make a great deal of such congiderations, but it may not be possible to dispose of this philosophy so easily. The essential character of materialism is not adherence to an exploded scientific theory, but the view that the world revealed to science is the primary, or even the only, reality. This view is still widely held. Admittedly the scientist no longer claims to know the character of the physical world as it really is, and he is prepared for revolutionary changes. He may even wish to abandon words like ‘matter’ altogether; but such terminological variations are not to be confused with a fundamental change of principle and attitude.
The objections to materialism will have to go deeper than this. On the materialistic view sensation—and also what we call thinking—is said sometimes to be a product, and sometimes to be a reflexion, of what we may still be permitted to call the material world. No doubt a reflexion, though the term seems ambiguous, may also be a product or event caused by the material world; but what we have to explain is how such a caused event can be knowledge of the material world. More generally, we have to ask ourselves how the material world, whatever be its character, can be known. If we are told dogmatically that this is just a fact behind which we cannot go, we are left in the presence of an unexplained mystery, a miracle which taxes our powers of credulity to the utmost. Philosophers, as a rule, do not like unexplained mysteries, and it is hard to see why they should accept this one in preference to others; and still harder to see how by so doing they can get rid of mysteries altogether.
But it is not our business here to refute materialism. The one indubitable fact we have to note is this. Materialism is, and is meant to be, and indeed is bound to be, fatal to religion. If the material world is the primary reality, God could at most be a secondary reality; that is to say, He could not be God. Materialism can function as a kind of religion—it can certainly suffer from religious aberrations like fanaticism; but it would be an unnecessary elaboration of the obvious to insist that it is essentially, as well as professedly, atheistic.
§ 3. Phenomenalism
If we are dissatisfied with materialism as a philosophy and are still looking for one homogeneous real world unlike the very mixed world of common sense, the obvious alternative is to fall back on what is given directly to sense proper uncontaminated by thought. Let us avoid all unnecessary complications about the causes of our perception and say boldly that the world is what we see and hear and touch and taste and smell. Everything else is derivative or even unreal—the bodies and electrons of the scientist as much as the immortal souls and intelligible universals and unknown substances of traditional philosophy. All of these, if they do not spring from verbal confusion or sheer mystification, are on this view only useful devices which enable us to predict with greater certainty what we are likely to see and hear and touch. We may say that we see tables and hear bells; but we should never lose grip of the fundamental truth that what we see is colours and what we hear is sounds. Only the secondary qualities—if among them we may include also apparent shapes and sizes and so on—can be given immediately to our senses, and we may call them sensa or sense-data, though they are sometimes ambiguously spoken of as sensations.
Those who take the view that the world is composed of sense-data, and that all else is derivative, are known as phenomenalists. The word ‘phenomenon’ is simply the Greek for what appears; and on this theory what appears is what appears directly to the senses, namely, sense-data. The classical exponent of phenomenalism is David Hume, although his modern followers are in many ways more sophisticated.
Phenomenalism seems at the moment to be under a cloud, and is sometimes said, even by thorough-going empiricists, to be dead at last. Its funeral oration has been pronounced in Mind by Mr. Isaiah Berlin, who has also done something to lay its unquiet ghost. Although its supporters, like most other philosophers, sometimes claim that they are only stating clearly what the ordinary man really believes, the doctrine is manifestly repugnant to common sense. It may seem even more repugnant to science, but this would be a mistake. In point of fact it received a new lease of life when the physicists had to abandon the hope of being able to illustrate their theories by constructing mechanical models.
So much has been written on this topic in recent years, and with such subtle variations, that we must here be satisfied with a bare allusion. Phenomenalism may be taken to deny the existence, not only of the permanent bodies believed in by common sense and of the particles accepted by the old-fashioned materialist, but also of whatever may be said by the modern physicist to fill time and space—if his assertions can be put in these terms. But more recent phenomenalists may reject this language as metaphysical. They prefer to state their position in linguistic terms, which would run something like this.
We employ two languages—a sense-datum language and a material-object language. Everything said in the material-object language can in principle be said in the sense-datum language, just as—to take a rough parallel—everything said about a committee can in principle be translated into statements about members of the committee. Hence a material object need not be regarded as an inferred entity (an entity inferred from sense-data), but as what is called a logical construction.
Whether or not it is possible thus to by—pass metaphysical problems need not here concern us. Phenomenalism, like materialism, is one of the great simplifying philosophies, and as such is worthy of respect. What is important for us is that in the process of simplification mind has to go the same way as matter. Mind, just as much as body, can be taken to be a logical construction (provided we do not ask what does the constructing): anything that can be said of it can in principle be translated into the language of sense-data and images. In the more metaphysical language of Hume a mind can be ‘nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement’.
Some of us may doubt whether these alleged translations from one language into another are possible even in principle—no one pretends that they are possible in practice. We may doubt, not whether we can, perhaps by an effort, see coloured shapes that are only coloured shapes, but whether coloured shapes can be directly given to sense without activity on our part, or can be called sense-data without misleading implications. We may also doubt whether the view that our perceptions are distinct existences can be other than a metaphysical superstition based on faulty analysis and unsupported by empirical evidence. We may even maintain that this philosophy fails to do justice to our knowledge of the world and of ourselves and is unable to explain how it itself could come into existence as a philosophy. But summary criticism and dogmatic rejection are out of place in dealing with any philosophy at which acute thinkers have laboured with the highest degree of subtlety. One thing at least is clear—the only thing that matters for our present purpose. If phenomenalism denies the existence of bodies and minds except as collections of sense-data or bundles of distinct perceptions, it must, to be consistent, deny equally the existence of God. If it reduces bodies and minds to the status of logical constructions, God cannot be more than a logical construction, and perhaps he cannot even be that. Phenomenalism, like materialism, so far as I can see, must be fatal to any kind of theistic religion.
This conclusion, it should be added parenthetically, takes phenomenalism strictly as the doctrine that only what is given to sense can be real. But since the combinations in philosophy are endless, it is possible, whether consistently or not, to be a phenomenalist about the so-called material world and yet to hold that we have a notion of mind—or of minds—which is independent of our senses. Such a view, which finds its most famous advocate in Bishop Berkeley, is manifestly compatible with religion, but it is far from being pure phenomenalism in the sense intended here.
Perhaps phenomenalism and materialism have one thing in common, in spite of their fundamental differences. Both of them take the world to be a mere aggregate—to be, if I may so express myself without disrespect, just one damned thing after another. If we take our world to be an aggregate or sum of parts, and confine our attention to the relations subsisting between one part and another, we may contribute to the philosophy of science, but it is hard to see how we can find any place for religious belief.
§ 4. Platonism
It is obvious enough that no philosophically simple world can be satisfactory to the religious consciousness. If we seek to find a world more adaptable to religion, let us try to combine sense-data and material objects within a more Platonic view—how much of it is actually to be found in Plato himself need not here concern us: some of my interpretations would be challenged by many scholars. All I am trying to do is to sketch very roughly the philosophers' world which has in fact been the European background of religion. I will ignore modern developments of mathematics and logic and will use traditional language without criticism, even if it may be sometimes slightly emotive and not always wholly clear.
A material object—let us call it for short ‘a body’—always appears to us by means of sensations or sense-data. Sense-data are appearances of a body; a body is the reality which appears. They are apprehended by sense; it is perceived by a combination of sense and thought. They are the sign; it is the thing signified. They are images or reflexions, often distorted, of it; it is their original or model. They cannot be without it; but it can be without them. They are conditioned by it, and it is their condition—the ground of their being and the explanation of their character. It is one; they are many. It is permanent; they are fleeting. It is intelligible; they are sensible. It is real; they are relatively unreal.
On this view sense-data are rather like shadows, or even like the images which appear in dreams.
The passage from the world of sense-data or of changing appearances to the world of real bodies is made, or at least justified, by a process of counting and weighing and measuring, which determines what we now call primary qualities. Although this process is an intellectual one, it must be based on units which are ultimately sensible. As elaborated by modern science, it no longer brings us to knowledge of comfortable solid bodies; but it still brings us to knowledge of what is measurable independently of the observer's personal sensibility. Fresh difficulties do arise, as I have indicated, when we cease to regard sense perception as direct awareness and assert that it is the result of a causal process; but these difficulties must here be ignored.
A more serious objection may be raised from a philosophical point of view. We are distinguishing between appearance and reality and supposing that appearances are unreal, or at any rate less real. We are manifestly preparing the way for a doctrine that there can be degrees of reality, and this—it may be held—is manifestly nonsense. Things cannot be more or less real. They are either real or else they are nothing at all.
This question need not be argued here. It would not be difficult to find support in ordinary language for either usage; but words have always to be understood in their context, and their context here is a whole philosophy. We must simply note that what is opaque to understanding is being treated as less real than what is intelligible—in the sense of being measurable and so describable by mathematics. This seems also to be the view of many scientists and materialistic philosophers, and it involves a distinction between existing and being real: we may say that a thing either exists or does not exist, but if it does exist, it can still be more or less real. We may even have to recognize that the word ‘exist’ itself may be used in different senses. But with Plato we make the further, and more dubious, assumption that not only the sensible, but the changeable as such, is opaque to the understanding, and that the intelligible must also be the permanent or unchanging.
If we adopt this last assumption, the world of bodies cannot be wholly intelligible or wholly real. Although it is permanent relatively to sense-data, it is for ever changing, or becoming, or being what it is not: ‘it tumbles about between being and not-being’—perhaps even more than Plato thought; and our measurements, however mathematical, are still based ultimately on sense. Hence our so-called knowledge of the world of bodies is only fallible opinion. If our craving for knowledge of reality is to be satisfied we must look elsewhere.
Where can we find such knowledge better than in the world of mathematics? Here we can examine by themselves the measurements and numbers and shapes and sizes in virtue of which alone bodies are intelligible. We can count numbers instead of sheep. We can discover the character of triangles and squares and cubes which are really triangles and squares and cubes instead of imperfect approximations to them. We gain genuine knowledge when we pass from the world of the surveyor to the world of the mathematician. Instead of trying to describe the irregular visible motions of the heavenly bodies, we can think out mathematically the relations of moving bodies to one another. We can deal with shapes and bodies and motions which are unaffected by the changes of their imperfect copies in the material world; which do not come into being or pass out of being; which are, in short, permanent and indeed timeless or eternal. In this way we can attain infallible knowledge of a world which is truly intelligible and truly real. This unchanging world is the condition and explanation of all that is intelligible in the changing world of bodies, just as the world of bodies is the condition and explanation of whatever may be intelligible in the flux of sense-data or sensible images.
But even this world of mathematics fails to satisfy our desire for unity and system and intelligibility. The thinking of the mathematician rests on unproved assumptions, and he is still so much involved with sense that he has to use visible diagrams, although it is not of these that he is thinking. Even his mathematical figures and motions cannot be separated from space and time, which seem to be neither wholly sensible nor wholly intelligible, if indeed they can be said to be at all. Because of this he is still involved in multiplicity: he has to deal with many ones, with many triangles, with many cubes and spheres. If he is to attain complete intelligibility, he must examine his assumptions and definitions and their relations to one another. He must pass to universals, to what Plato called pure Forms or eternal Ideas, to oneness itself, triangularity itself, and so on. Each of these Forms is one and not many: triangularity is the same in all mathematical triangles, in all triangular bodies, and even in all triangular images. The Forms alone are truly intelligible, and are the source of all intelligibility in everything else. According to Plato, they are the ultimate reality and are grasped by pure intelligence without any sensuous aid other than that of words.
Here then beyond the world of images and the world of bodies and the world of mathematical objects we have a fourth world—the real and intelligible world of pure eternal Forms grasped by pure intelligence. Yet though each Form is one, there are many Forms: we have still to understand them as one system and to grasp the principle of their systematic unity. This principle Plato finds in what he calls the Form of the Good, or Goodness itself; and he believes it can be apprehended, or at least approached, through a process of logical thinking which he calls dialectic. In it we find the original or model of all reality, the unconditioned condition, the ultimate ground and explanation, of the being and nature of everything else.
It will be observed that this whole ascent from sensible images to the Form of the Good is an intellectual one and in its highest stages appears almost to be pure logic. When Plato, it is recorded, gave notice of a public lecture on the Good, the large and fashionable audience which came to hear him was disappointed to find that he talked mostly in mathematical symbols—just like a modern logician. But there is for him another side to all this. Severe as is the long intellectual training necessary for philosophy, it must be accompanied by a practical and moral training no less severe; and the Form of the Good is a guide to life as well as an explanation of reality. Furthermore, we are told that the Form of the Good is beyond knowledge and truth and even beyond being. We are also told by Plato that he would never commit his deepest thoughts to writing. For some men perhaps, at the end of the process of dialectic, there blazes out, it may be suddenly, a vision of transcendent reality, where words are no longer adequate or necessary, and where verbal description, if employed at all, must take the form of poetry and myth. There is thus a mystical side to Plato, which was developed further by some of his successors; but this does not alter the fact that his philosophy was meant to be accepted or rejected as a piece of logical thinking.
All this, it may be said, is utterly ingenuous. In a sense it is, though perhaps it is not more ingenuous than a great deal we have to listen to to-day. There are still echoes of the doctrine, and more than echoes, in such modern thinkers as Santayana and Whitehead. Nevertheless we may agree that Plato was led to claim too much for the new methods in mathematics and philosophy, perhaps because of the intense intellectual excitement they aroused. Few of us realize vividly enough ‘the glory that was Greece’—the escape from the savagery and superstitition of barbarism to the controlled and reasonable life of free men, the passage from chaos to cosmos (or order). The escape was not complete—it never is—but no wonder there was something like a worship of reason and a passionate hope that by rational methods men could make amazing progress, not merely in science, but in moral and political life. Perhaps this hope has never wholly died: it became strong again in Europe in the age of the Enlightenment after the discoveries of Newton. We may wish we had more of it to-day. If it led Plato to claim too much for mathematics and philosophy, to plunge beyond the limits of our finite understanding, to ‘hypostatize’ an eternal and intelligible world of which the philosopher could have infallible knowledge by means of pure intelligence unmixed with sense, this is no reason why we should belittle it. In spite of weaknesses and obscurities—and what philosophy is free from these?—his attempt to ‘carve reality at the joints’ still stands out as one of the greatest achievements of the human mind.
§ 5. Philosophy and religion
This philosophy is as favourable to religion as phenomenalism and materialism are unfavourable: it is indeed itself almost a religion as well as a philosophy. It formed, at least in its later and more mystical developments, the background of early Christian thinking, very notably in St. Augustine, who did so much to determine the direction of traditional theology. As transmuted by Aristotle and adjusted by Aquinas—in which there was loss as well as gain—it became the official philosophy of the Christian Church. The Reformers were moved by moral rather than theoretical considerations, and they thought, perhaps rightly, that there was a danger of religion being smothered by philosophical subtleties; but almost without question they retained, in the very heart of theological doctrines about the Trinity and the Incarnation, the philosophical concepts of substance and essence which are direct developments of the Platonic Forms. Since then philosophy has gone its own independent way, and in its attempts to keep pace with the advance of science has to its credit achievements based on a far wider knowledge than was possible for Aristotle or for Plato. Theologians have too often either condemned these developments and harked back to Aquinas or else have tried to do without philosophy altogether—or at best have selected out of it whatever seemed to fit their purposes. This may be too harsh a judgement, and there is something to be said for the view that religion should not be committed to any philosophy by which it must stand or fall; but so far as theology is rational, it is in a weak position if it is without any means of philosophical defence. It is in a hopeless position if it attempts to defend itself by philosophical arguments—or still worse by philosophical sophistries—incapable of standing up to any serious rational scrutiny.
From a religious point of view the attraction of the Platonic philosophy is that it claims to give knowledge of an abiding and eternal reality beyond the world of sense and matter and space and time; but it is precisely this claim which modern philosophy has tended more and more to reject. Even Aristotle may be said to have begun this movement when he denied the separate and independent existence of the Forms; but although he was always cavilling at his master Plato, he often finishes up by saying very much the same kind of thing. So long as we hold that there are intelligible universal or Forms or essences or substances which can be grasped by pure intelligence, perhaps it does not greatly matter to religion whether these exist apart from material and sensible objects or only in them. But if we say that all this is only high-falutin' nonsense and that our glorified essences are in fact mere names applied to objects that look alike, then we seem to be confined to a purely sensible or material world of contingent events in space and time; and in such a world there can by definition be no room for God.
In all this nothing has been said of mind or soul, or of the way in which it can know the different grades of reality. Platonism is one form of what is called ‘realism’; and, broadly speaking, whatever may have to be done by mind on the way to knowledge, knowledge is supposed to be a direct vision of reality as it is in itself. This is believed possible on the basis of a kinship between mind and its object. So far as the soul is aware of changing sensible objects, it is itself sensuous and changing; so far as it is aware of eternal and intelligible objects, it too is eternal as well as intelligent; and if the eternal is the real, the soul is most real so far as it is directed to eternal objects both in thought and in action. The Form of the Good, the unconditioned reality which is the source of all truth and knowledge and being and yet is somehow beyond all these, may seem to fall short of God in so far as it is nothing more; and the soul of man may seem to cling precariously to the marble facade of a hierarchy of intelligible Forms stretching upwards beyond his vision. But if this supreme Form is not merely supremely real and supremely intelligible in itself, but is also supreme intelligence—as it conies to be in the more mystical developments of the doctrine—then indeed we have a philosophy in which the religious man may find satisfaction, not only for his head, but for his heart.
It is not surprising that in all ages religious thinkers have sought to go back to some kind of Platonism. It is this which in its various modifications is claimed as the perennial philosophy—philosophia perennis; and there are some who profess to find it in the East as well as in the West. Yet the predicament of religion to-day lies partly in the fact that most modern philosophy is disposed to question the Platonic claim. Is it really possible for us, with our finite minds and our dependence on sense and matter, to obtain knowledge of the supreme reality? Before we are carried away by the eloquence of the divine Plato, ought we not to turn back and reflect on our own limited capacities and ask ourselves how such knowledge can be possible? The Greeks were less troubled by this question than we are to-day; but, as a matter of historical fact, the Academy which Plato founded, and which lasted for a thousand years until it was closed by an intolerant Church, turned in the end to a doctrine of scepticism. We are still told, though not by many, that it is sheer confusion to ask questions about the possibility of our own knowledge; but perhaps Christian theology, in its concern with the individual human soul and with the need for revelation as opposed to reason, has itself helped to stimulate such questions. The developments of science have made these enquiries inevitable. Even if modern thinking is entirely on the wrong lines—a very difficult assumption—we are compelled to consider, not merely the character of the known world, but also the nature of the mind which knows it.
Perhaps after all it is a mistake to speak of the philosophers' world. There is only one world which we all try to know from our different points of view. Of that world man is only a part, and yet a part which claims to know other parts or even to know the whole. Perhaps the first business of philosophy is to examine this claim and to study the powers and limitations of the fallible creatures who make it.