Philosophy

Perhaps it might be expected that I should begin with a definition of “philosophy”, but, rightly or wrongly, I do not propose to do so. The definition of “philosophy” will vary according to the philosophy we adopt; all that we can say to begin with is that there are certain problems, which certain people find interesting, and which do not, at least at present, belong to any of the special sciences. These problems are all such as to raise doubts concerning what commonly passes for knowledge; and if the doubts are to be answered, it can only be by means of a special study, to which we give the name “philosophy”. Therefore the first step in defining “philosophy” is the indication of these problems and doubts, which is also the first step in the actual study of philosophy. There are some among the traditional problems of philosophy that do not seem to me to lend themselves to intellectual treatment, because they transcend our cognitive powers; such problems I shall not deal with. There are others, however, as to which, even if a final solution is not possible at present, yet much can be done to show the direction in which a solution is to be sought, and the kind of solution that may in time prove possible. Philosophy arises from an unusually obstinate attempt to arrive at real knowledge. What passes for knowledge in ordinary life suffers from three defects: it is cocksure, vague, and self-contradictory. The first step towards philosophy consists in becoming aware of these defects, not in order to rest content with a lazy scepticism, but in order to substitute an amended kind of knowledge which shall be tentative, precise, and self-consistent. There is of course another quality which we wish our knowledge to possess, namely comprehensiveness: we wish the area of our knowledge to be as wide as possible. But this is the business of science rather than of philosophy. A man does not necessarily become a better philosopher through knowing more scientific facts; it is principles and methods and general conceptions that he should learn from science if philosophy is what interests him. The philosopher’s work is, so to speak, at the second remove from crude fact. Science tries to collect facts into bundles by means of scientific laws; these laws, rather than the original facts, are the raw material of philosophy. Philosophy involves a criticism of scientific knowledge, not from a point of view ultimately different from that of science, but from a point of view less concerned with details and more concerned with the harmony of the whole body of special sciences. The special sciences have all grown up by the use of notions derived from common sense, such as things and their qualities, space, time, and causation. Science itself has shown that none of these common-sense notions will quite serve for the explanation of the world; but it is hardly the province of any special science to undertake the necessary reconstruction of fundamentals. This must be the business of philosophy. I want to say, to begin with, that I believe it to be a business of very great importance. I believe that the philosophical errors in common-sense beliefs not only produce confusion in science, but also do harm in ethics and politics, in social institutions, and in the conduct of everyday life. It will be no part of my business, in this volume, to point out these practical effects of a bad philosophy: my business will be purely intellectual. But if I am right, the intellectual adventures which lie before us have effects in many directions which seem, at first sight, quite remote from our theme. The effect of our passions upon our beliefs forms a favourite subject of modern psychologists; but the converse effect, that of our beliefs upon our passions, also exists, though it is not such as an old-fashioned intellectualist psychology would have supposed. Although I shall not discuss it, we shall do well to bear it in mind, in order to realise that our discussions may have bearings upon matters lying outside the sphere of pure intellect. I mentioned a moment ago three defects in common beliefs, namely, that they are cocksure, vague, and self-contradictory. It is the business of philosophy to correct these defects so far as it can, without throwing over knowledge altogether. To be a good philosopher, a man must have a strong desire to know, combined with great caution in believing that he knows; he must also have logical acumen and the habit of exact thinking. All these, of course, are a matter of degree. Vagueness, in particular, belongs, in some degree, to all human thinking; we can diminish it indefinitely, but we can never abolish it wholly. Philosophy, accordingly, is a continuing activity, not something in which we can achieve final perfection once for all. In this respect, philosophy has suffered from its association with theology. Theological dogmas are fixed, and are regarded by the orthodox as incapable of improvement. Philosophers have too often tried to produce similarly final systems: they have not been content with the gradual approximations that satisfied men of science. In this they seem to me to have been mistaken. Philosophy should be piecemeal and provisional like science; final truth belongs to heaven, not to this world. The three defects which I have mentioned are interconnected, and by becoming aware of any one we may be led to recognise the other two. I will illustrate all three by a few examples. Let us take first the belief in common objects, such as tables and chairs and trees. We all feel quite sure about these in ordinary life, and yet our reasons for confidence are really very inadequate. Naive common sense supposes that they are what they appear to be, but that is impossible, since they do not appear exactly alike to any two simultaneous observers; at least, it is impossible if the object is a single thing, the same for all observers. If we are going to admit that the object is not what we see, we can no longer feel the same assurance that there is an object; this is the first intrusion of doubt. However, we shall speedily recover from this set-back, and say that of course the object is “really” what physics says it is.1 Now physics says that a table or a chair is “really” an incredibly vast system of electrons and protons in rapid motion, with empty space in between. This is all very well. But the physicist, like the ordinary man, is dependent upon his senses for the existence of the physical world. If you go up to him solemnly and say, “would you be so kind as to tell me, as a physicist, what a chair really is”, you will get a learned answer. But if you say, without preamble: “Is there a chair there?” he will say: “Of course there is; can’t you see it?” To this you ought to reply in the negative. You ought to say, “No, I see certain patches of colour, but I don’t see any electrons or protons, and you tell me that they are what a chair consists of”. He may reply: “Yes, but a large number of electrons and protons close together look like a patch of colour”. What do you mean by “look like”? you will then ask. He is ready with an answer. He means that light-waves start from the electrons and protons (or, more probably, are reflected by them from a source of light), reach the eye, have a series of effects upon the rods and cones, the optic nerve, and the brain, and finally produce a sensation. But he has never seen an eye or an optic nerve or a brain, any more than he has seen a chair; he has only seen patches of colour which, he says, are what eyes “look like.” That is to say, he thinks that the sensation you have when (as you think) you see a chair, has a series of causes, physical and psychological, but all of them, on his own showing, lie essentially and forever outside experience. Nevertheless, he pretends to base his science upon observation. Obviously there is here a problem for the logician, a problem belonging not to physics, but to quite another kind of study. This is a first example of the way in which the pursuit of precision destroys certainty. 1 I am not thinking here of the elementary physics to be found in a school text-book; I am thinking of modern theoretical physics, more particularly as regards the structure of atoms, as to which I shall have more to say in later chapters. The physicist believes that he infers his electrons and protons from what he perceives. But the inference is never clearly set forth in a logical chain, and, if it were, it might not look sufficiently plausible to warrant much confidence. In actual fact, the whole development from common-sense objects to electrons and protons has been governed by certain beliefs, seldom conscious, but existing in every natural man. These beliefs are not unalterable, but they grow and develop like a tree. We start by thinking that a chair is as it appears to be, and is still there when we are not looking. But we find, by a little reflection, that these two beliefs are incompatible. If the chair is to persist independently of being seen by us, it must be something other than the patch of colour we see, because this is found to depend upon conditions extraneous to the chair, such as how the light falls, whether we are wearing blue spectacles, and so on. This forces the man of science to regard the “real” chair as the cause (or an indispensable part of the cause) of our sensations when we see the chair. Thus we are committed to causation as an a priori belief without which we should have no reason for supposing that there is a “real” chair at all. Also, for the sake of permanence we bring in the notion of substance: the “real” chair is a substance, or collection of substances, possessed of permanence and the power to cause sensations. This metaphysical belief has operated, more or less unconsciously, in the inference from sensations to electrons and protons. The philosopher must drag such beliefs into the light of day, and see whether they still survive. Often it will be found that they die on exposure. Let us now take up another point. The evidence for a physical law, or for any scientific law, always involves both memory and testimony. We have to rely both upon what we remember to have observed on former occasions, and on what others say they have observed. In the very beginnings of science, it may have been possible sometimes to dispense with testimony; but very soon every scientific investigation began to be built upon previously ascertained results, and thus to depend upon what others had recorded. In fact, without the corroboration of testimony we should hardly have had much confidence in the existence of physical objects. Sometimes people suffer from hallucinations, that is to say, they think they perceive physical objects, but are not confirmed in this belief by the testimony of others. In such cases, we decide that they are mistaken. It is the similarity between the perceptions of different people in similar situations that makes us feel confident of the external causation of our perceptions; but for this, whatever naive beliefs we might have had in physical objects would have been dissipated long ago. Thus memory and testimony are essential to science. Nevertheless, each of these is open to criticism by the sceptic. Even if we succeed, more or less, in meeting his criticism, we shall, if we are rational, be left with a less complete confidence in our original beliefs than we had before. Once more, we shall become less cocksure as