Philosophy

we become more accurate. Both memory and testimony lead us into the sphere of psychology. I shall not at this stage discuss either beyond the point at which it is clear that there are genuine philosophical problems to be solved. I shall begin with memory. Memory is a word which has a variety of meanings. The kind that I am concerned with at the moment is the recollection of past occurrences. This is so notoriously fallible that every experimenter makes a record of the result of his experiment at the earliest possible moment: he considers the inference from written words to past events less likely to be mistaken than the direct beliefs which constitute memory. But some time, though perhaps only a few seconds, must elapse between the observation and the making of the record, unless the record is so fragmentary that memory is needed to interpret it. Thus we do not escape from the need of trusting memory to some degree. Moreover, without memory we should not think of interpreting records as applying to the past, because we should not know that there was any past. Now, apart from arguments as to the proved fallibility of memory, there is one awkward consideration which the sceptic may urge. Remembering, which occurs now, cannot possibly—he may say—prove that what is remembered occurred at some other time, because the world might have sprung into being five minutes ago, exactly as it then was, full of acts of remembering which were entirely misleading. Opponents of Darwin, such as Edmund Gosse’s father, urged a very similar argument against evolution. The world, they said, was created in 4004 B.C., complete with fossils, which were inserted to try our faith. The world was created suddenly, but was made such as it would have been if it had evolved. There is no logical impossibility about this view. And similarly there is no logical impossibility in the view that the world was created five minutes ago, complete with memories and records. This may seem an improbable hypothesis, but it is not logically refutable. Apart from this argument, which may be thought fantastic, there are reasons of detail for being more or less distrustful of memory. It is obvious that no direct confirmation of a belief about a past occurrence is possible, because we cannot make the past recur. We can find confirmation of an indirect kind in the revelations of others and in contemporary records. The latter, as we have seen, involve some degree of memory, but they may involve very little, for instance when a shorthand report of a conversation or speech has been made at the time. But even then, we do not escape wholly from the need of memory extending over a longer stretch of time. Suppose a wholly imaginary conversation were produced for some criminal purpose, we should depend upon the memories of witnesses to establish its fictitious character in a law-court. And all memory which extends over a long period of time is very apt to be mistaken; this is shown by the errors invariably found in autobiographies. Any man who comes across letters which he wrote many years ago can verify the manner in which his memory has falsified past events. For these reasons, the fact that we cannot free ourselves from dependence upon memory in building up knowledge is, prima facie, a reason for regarding what passes for knowledge as not quite certain. The whole of this subject of memory will be considered more carefully in later chapters. Testimony raises even more awkward problems. What makes them so awkward is the fact that testimony is involved in building up our knowledge of physics, and that, conversely, physics is required in establishing the trustworthiness of testimony. Moreover, testimony raises all the problems connected with the relation of mind and matter. Some eminent philosophers, e.g. Leibniz, have constructed systems according to which there would be no such thing as testimony, and yet have accepted as true many things which cannot be known without it. I do not think philosophy has quite done justice to this problem, but a few words will, I think, show its gravity. For our purposes, we may define testimony as noises heard, or shapes seen, analogous to those which we should make if we wished to convey an assertion, and believed by the hearer or seer to be due to someone else’s desire to convey an assertion. Let us take a concrete instance: I ask a policeman the way, and he says, “Fourth turn to the right, third to the left.” That is to say, I hear these sounds, and perhaps I see what I interpret as his lips moving. I assume that he has a mind more or less like my own, and has uttered these sounds with the same intention as I should have had if I had uttered them, namely to convey information. In ordinary life, all this is not, in any proper sense, an inference; it is a belief which arises in us on the appropriate occasion. But if we are challenged, we have to substitute inference for spontaneous belief, and the more the inference is examined the more shaky it looks. The inference that has to be made has two steps, one physical and one psychological. The physical inference is of the sort we considered a moment ago, in which we pass from a sensation to a physical occurrence. We hear noises, and think they proceed from the policeman’s body. We see moving shapes, and interpret them as physical motions of his lips. This inference, as we saw earlier, is in part justified by testimony; yet now we find that it has to be made before we can have reason to believe that there is any such thing as testimony. And this inference is certainly sometimes mistaken. Lunatics hear voices which other people do not hear; instead of crediting them with abnormally acute hearing, we lock them up. But if we sometimes hear sentences which have not proceeded from a body, why should this not always be the case? Perhaps our imagination has conjured up all the things that we think others have said to us. But this is part of the general problem of inferring physical objects from sensations, which, difficult as it is, is not the most difficult part of the logical puzzles concerning testimony. The most difficult part is the inference from the policeman’s body to his mind. I do not mean any special insult to policemen; I would say the same of politicians and even of philosophers. The inference to the policeman’s mind certainly may be wrong. It is clear that a maker of wax-works could make a life-like policeman and put a gramophone inside him, which would cause him periodically to tell visitors the way to the most interesting part of the exhibition at the entrance to which he would stand. They would have just the sort of evidence of his being alive that is found convincing in the case of other policemen. Descartes believed that animals have no minds, but are merely complicated automata. Eighteenth-century materialists extended this doctrine to men. But I am not now concerned with materialism; my problem is a different one. Even a materialist must admit that, when he talks, he means to convey something, that is to say, he uses words as signs, not as mere noises. It may be difficult to decide exactly what is meant by this statement, but it is clear that it means something, and that it is true of one’s own remarks. The question is: Are we sure that it is true of the remarks we hear, as well as of those we make? Or are the remarks we hear perhaps just like other noises, merely meaningless disturbances of the air? The chief argument against this is analogy: the remarks we hear are so like those we make that we think they must have similar causes. But although we cannot dispense with analogy as a form of inference, it is by no means demonstrative, and not infrequently leads us astray. We are therefore left, once more, with a prima facie reason for uncertainty and doubt. This question of what we mean ourselves when we speak brings me to another problem, that of introspection. Many philosophers have held that introspection gave the most indubitable of all knowledge; others have held that there is no such thing as introspection. Descartes, after trying to doubt everything, arrived at “I think, therefore I am”, as a basis for the rest of knowledge. Dr. John B. Watson the behaviourist holds, on the contrary, that we do not think, but only talk. Dr. Watson, in real life, gives as much evidence of thinking as anyone does, so if he is not convinced that he thinks, we are all in a bad way. At any rate, the mere existence of such an opinion as his, on the part of a competent philosopher, must suffice to show that introspection is not so certain as some people have thought. But let us examine this question a little more closely. The difference between introspection and what we call perception of external objects seems to me to be connected, not with what is primary in our knowledge, but with what is inferred. We think, at one time, that we are seeing a chair; at another, that we are thinking about philosophy. The first we call perception of an external object; the second we call introspection. Now we have already found reason to doubt external perception, in the full-blooded sense in which common-sense accepts it. I shall consider later what there is that is indubitable and primitive in perception; for the moment, I shall anticipate by saying that what is indubitable in “seeing a chair” is the occurrence of a certain pattern of colours. But this occurrence, we shall find, is connected with me just as much as with the chair; no one except myself can see exactly the pattern that I see. There is thus something subjective and private about what we take to be external perception, but this is concealed by precarious extensions into the physical world. I think introspection, on the contrary, involves precarious extensions into the mental world: shorn of these, it is not very different from external perception shorn of its extensions. To make this clear, I shall try to show what we know to be occurring when, as we say, we think about philosophy. Suppose, as the result of introspection, you arrive at a belief which you express in the words: “I am now believing that mind is different from matter”. What do you know, apart from inferences, in such a case? First of all, you must cut out the word “I”: the person who believes is an inference, not part of what you know immediately. In the second place, you must be careful about the word “believing”: I am not now concerned with what this word should mean in logic or theory of knowledge; I am concerned with what it can mean when used to describe a direct experience. In such a case, it would seem that it can only describe a certain kind of feeling. And as for the proposition you think you are believing, namely, “mind is different from matter”, it is very difficult to say what is really occurring when you think you believe it. It may be mere words, pronounced, visualised, or in auditory or motor images. It may be images of what the words “mean”, but in that case it will not be at all an accurate representation of the logical content of the proposition. You may have an image of a statue of Newton “voyaging through strange seas of thought alone”, and another image of a stone rolling downhill, combined with the words “how different!” Or you may think of the difference between composing a lecture and eating your dinner. It is only when