Philosophy

by Bertrand Russell

Let us now take up Dr. Watson’s view. We shall find, if I am not mistaken, that his position also is to a very large extent valid. That being so, we shall seek to find an intermediate opinion, accepting what seems valid and rejecting what seems doubtful in the contentions of both protagonists.

Dr. Watson’s view as to what is most certain is one which is in entire accordance with common sense. All psychological matters the plain man regards as more or less open to question, but he has no doubts about his office, his morning train, the tax-collector, the weather, and the other blessings of this life. It may amuse him, in an idle hour, to listen to some one playing with the idea that life is a dream, or suggesting that the thoughts of the people in the train are more real than the train. But unless he is a philosophical lecturer, he does not countenance such notions in business hours. Who can imagine a clerk in an office conceiving metaphysical doubts as to the existence of his boss? Or would any railroad president regard with favour the theory that his railroad is only an idea in the minds of the shareholders? Such a view, he would say, though it is often sound as regards gold-mines, is simply silly when it comes to a railroad: anybody can see it, and can get himself run over if he wanders on the tracks under the impression that they do not exist. Belief in the unreality of matter is likely to lead to an untimely death, and that, perhaps, is the reason why this belief is so rare, since those who entertained it died out. We cannot dismiss the common-sense outlook as simply silly, since it succeeds in daily life; if we are going to reject it in part, we must be sure that we do so in favor of something equally tough as a means of coping with practical problems.

Descartes says: I think, therefore I am. Watson says: There are rats in mazes, therefore I don’t think. At least, a parodist might thus sum up his philosophy. What Watson really says is more like this: (1) The most certain facts are those which are public, and can be confirmed by the testimony of a number of observers. Such facts form the basis of the physical sciences: physics, chemistry, biology, anatomy, physiology, to mention only those that are relevant to the matter in question. (2) The physical sciences are capable of affording an explanation of all the publicly observable facts about human behaviour. (3) There is no reason to suppose that there are any facts about human beings that can be known only in some other way. (4) In particular, “introspection”, as a means of discovering by self-observation things that are in principle undiscoverable by observation of others, is a pernicious superstition, which must be swept away before any really sound knowledge of man becomes possible. (5) And, as a corollary, there is no reason to believe in the existence of “thought” as opposed to speech and other bodily behaviour.

I have numbered the above propositions, as it is important to keep them separate. On the whole, (1), (2), and (3) seem to me to be true, but (4) and (5) seem to me to be false. Behaviourists, I think, incline to the view that (4) and (5) follow from (1), (2), and (3); but this view I attribute to what I should regard as errors concerning the basis of physics. That is why it was necessary to discuss physics before coming to a decision on this question of self-observation. But let us examine each of the above propositions in turn.

(1) It is true that the facts upon which the physical sciences are based are all of them public, in the sense that many men can observe them. If a phenomenon is photographed, any number of people can inspect the photograph. If a measurement is made, not only may several people be present, but others can repeat the experiment. If the result does not confirm the first observer, the supposed fact is rejected. The publicity of physical facts is always regarded as one of the greatest assets of physics. On a common-sense basis, therefore, the first of the propositions in which we have summed up the behaviourist philosophy must be admitted.

There are, however, some very important provisos which must be mentioned. In the first place, a scientific observer is not expected to note his integral reaction to a situation, but only that part of it which experience leads him to regard as “objective”, i.e. the same as the reaction of any other competent observer. This process of learning to note only “objective” features in our reaction is, as we have seen, begun in infancy; training in science only carries it further. A “good” observer does not mention what is peculiar to himself in his reaction. He does not say: “A boring speck of light danced about, causing me eye-fatigue and irritation; finally it settled at such-and-such a point.” He says simply: “The reading was such-and-such”. All this objectivity is a result of training and experience. One may say, in fact, that very few men have the “right” reaction to a scientific situation. Therefore an immense amount of theory is mixed up with what passes in science as pure observation. The nature and justification of this theory is a matter requiring investigation.

In the second place, we must not misinterpret the nature of the publicity in the case of physical phenomena. The publicity consists in the fact that a number of people make closely similar reactions at a given moment. Suppose, for example, that twelve men are told to watch a screen for the appearance of a bright light, and to say “now” when it appears. Suppose the experimenter hears them all just when he himself sees the light; then he has good reason to believe that they have each had a stimulus similar to his. But physics compels us to hold that they have had twelve separate stimuli, so that when we say they have all seen the same light we can only legitimately mean that their twelve stimuli had a common causal origin. In attributing our perceptions to a normal causal origin outside ourselves, we run a certain risk of error, since the origin may be unusual: there may be reflection or refraction on the way to the eye, there may be an unusual condition of the eye or optic nerve or brain. All these considerations give a certain very small probability that, on a given occasion, there is not such an outside cause as we suppose. If, however, a number of people concur with us, i.e. simultaneously have reactions which they attribute to an outside cause that can be identified with the one we had inferred, then the probability of error is enormously diminished. This is exactly the usual case of concurrent testimony. If twelve men, each of whom lies every other time that he speaks, independently testify that some event has occurred, the odds in favour of their all speaking the truth are 4095 to 1. The same sort of argument shows that our public senses, when confirmed by others, are probably speaking the truth, except where there are sources of collective illusion such as mirage or suggestion.

In this respect, however, there is no essential difference between matters of external observation and matters of self-observation. Suppose, for example, that, for the first time in your life, you smell assafœtida. You say to yourself “that is a most unpleasant smell”. Now unpleasantness is a matter of self-observation. It may be correlated with physiological conditions which can be observed in others, but it is certainly not identical with these, since people knew that things were pleasant and unpleasant before they knew about the physiological conditions accompanying pleasure and its opposite. Therefore when you say “that smell is unpleasant” you are noticing something that does not come into the world of physics as ordinarily understood. You are, however, a reader of psycho-analysis, and you have learned that sometimes hate is concealed love and love is concealed hate. You say to yourself, therefore: “Perhaps I really like the smell of assafœtida, but am ashamed of liking it”. You therefore make your friends smell it, with the result that you soon have no friends. You then try children, and finally chimpanzees. Friends and children give verbal expression to their disgust: chimpanzees are expressive, though not verbal. All these facts lead you to state: “The smell of assafœtida is unpleasant”. Although self-observation is involved, the result has the same kind of certainty, and the same kind of objective verification, as if it were one of the facts that form the empirical basis of physics.

(2) The second proposition, to the effect that the physical sciences are capable of affording an explanation of all the publicly observable facts about human behaviour, is one as to which it is possible to argue endlessly. The plain fact is that we do not yet know whether it is true or false. There is much to be said in its favour on general scientific grounds, particularly if it is put forward, not as a dogma, but as a methodological precept, a recommendation to scientific investigators as to the direction in which they are to seek for solution of their problems. But so long as much of human behaviour remains unexplained in terms of physical laws, we cannot assert dogmatically that there is no residue which is theoretically inexplicable by this method. We may say that the trend of science, so far, seems to render such a view improbable, but to say even so much is perhaps rash, though, for my part, I should regard it as still more rash to say that there certainly is such a residue. I propose, therefore, as a matter of argument, to admit the behaviourist position on this point, since my objections to behaviourism as an ultimate philosophy come from quite a different kind of considerations.

(3) The proposition we are now to examine may be stated as follows: “All facts that can be known about human beings are known by the same method by which the facts of physics are known.” This I hold to be true, but for a reason exactly opposite to that which influences the behaviourist. I hold that the facts of physics, like those of psychology, are obtained by what is really self-observation, although common sense mistakenly supposes that it is observation of external objects. As we saw in [Chapter XIII], your visual, auditory, and other percepts are all in your head, from the standpoint of physics. Therefore, when you “see the sun”, it is, strictly speaking, an event in yourself that you are knowing: the inference to an external cause is more or less precarious, and is on occasion mistaken. To revert to the assafœtida: it is by a number of self-observations that you know that the smell of assafœtida is unpleasant, and it is by a number of self-observations that you know that the sun is bright and warm. There is no essential difference between the two cases. One may say that the data of psychology are those private facts which are not very directly linked with facts outside the body, while the data of physics are those private facts which have a very direct causal connection with facts outside the body. Thus physics and psychology have the same method; but this is rather what is commonly taken to be the special method of psychology than what is regarded as the method of physics. We differ from the behaviourist in assimilating physical to psychological method, rather than the opposite.