This whole matter is connected with the distinction between sentences and single words, which we found important when we were discussing language. But even when we confine ourselves to single words, there are difficulties in Dr. Watson’s view. Cases are alleged in which children, after learning to speak, can recall incidents which occurred before they could speak, and describe them in correct words. This would show that the memory had persisted in a non-verbal form throughout the period before they learned to speak, and had only subsequently found verbal expression. Such extreme incidents are rare and might be questioned, but in a less extreme form it ought not to be difficult to obtain examples of the same sort of thing. Suppose, for example, that a young child hurt his wrist badly before he knew the word “wrist”, and that some time afterwards he learnt it; I should not be surprised if he could relate that he had hurt his wrist. Such instances, however, would not refute the essence of Watson’s theory. He would allow “visceral” memory, for example, and the association with the word “wrist” might be grafted on to this. The real difficulty in Dr. Watson’s view, to my mind, is the fact that our sentence may vary verbally as much as it likes so long as it retains the same “meaning”, and that we clearly do not rehearse to ourselves beforehand all the possible sentences having the “meaning” in question.
It should be realised that behaviourism loses much of its attractiveness if it is compelled to postulate movements that no one can observe and that there is no other reason to assume. Dr. Broad, in his book on The Mind and its Place in Nature, distinguishes between “molar” and “molecular” behaviourism: the former assumes only such bodily movements as can be observed, while the latter allows and utilises hypothetical minute movements, more especially in the brain. Now here we must make a distinction. Physics believes in a large number of phenomena which are too minute to be observed even with the strongest microscope, and if physics is at all correct, there must be minute movements in all parts of a human body, of a sort which we can never hope to see. We cannot reasonably demand of the behaviourist that he should abstain from an hypothesis which physics asserts for very good reasons. And in the process which leads from stimulus to reaction there are bound to be small occurrences in the brain, which, though they cannot be observed, are essential to the physiological explanation of what occurs. But when the behaviourist assumes small occurrences for which there is no ground in physics, and which are needed solely in order to safeguard his theory, he is in a less strong position. Dr. Watson asserts, for instance, that whenever we “think” there are small movements in the larynx which are beginnings of the movements we should make as if we spoke words out loud. It may be that this is true; certainly I am not prepared to deny it. But I am not prepared to say that it must be true merely because, if it were not, behaviourism would be false. We do not know in advance that behaviourism is true; we have to find out whether it will explain observed facts. Whenever it has to postulate something unobserved merely in order to avoid a refutation, it weakens its case. And if it maintains, as, from Dr. Watson’s language, it seems to do, that we only remember an occurrence by forming a verbal habit in connection with it, then it is obliged to postulate much implicit use of words of which we have no evidence.
To sum up this discussion. While it is quite possible, by behaviourist methods, to ascertain whether a person remembers a past occurrence or not, unless he is deliberately obstructing the observer, and while much memory can be quite adequately explained as habit, there do seem to be great difficulties in the view that memory consists entirely of habit, at least in the case of the recollection of an event. These difficulties seem insuperable if we suppose memory to be essentially a verbal habit. They are not insuperable if we postulate sufficient minute unobservable bodily movements. We have not considered whether they can be overcome by introducing data derived from introspection, since we wish, for the present, to maintain a strictly objective attitude to human behaviour. The introspective discussion of memory will be taken up at a later stage.
[CHAPTER VII]
INFERENCE AS A HABIT
In this chapter, we are concerned with inference as it can be observed when practised by some one else. Inference is supposed to be a mark of intelligence and to show the superiority of men to machines. At the same time, the treatment of inference in traditional logic is so stupid as to throw doubt on this claim, and syllogistic inference, which was taken as the type from Aristotle to Bacon (exclusive), is just the sort of thing that a calculating machine could do better than a professor. In syllogistic inference, you are supposed to know already that all men are mortal and that Socrates is a man; hence you deduce, what you never suspected before, that Socrates is mortal. This form of inference does actually occur, though very rarely. The only instance I have ever heard of was supplied by Dr. F. C. S. Schiller. He once produced a comic number of the philosophical periodical Mind, and sent copies to various philosophers, among others to a certain German, who was much puzzled by the advertisements. But at last he argued: “Everything in this book is a joke, therefore the advertisements are jokes”. I have never come across any other case of new knowledge obtained by means of a syllogism. It must be admitted that, for a method which dominated logic for two thousand years, this contribution to the world’s stock of information cannot be considered very weighty.
The inferences that we actually make in daily life differ from those of syllogistic logic in two respects, namely, that they are important and precarious, instead of being trivial and safe. The syllogism may be regarded as a monument to academic timidity: if an inference might be wrong, it was dangerous to draw it. So the mediæval monks, in their thinking as in their lives, sought safety at the expense of fertility.
With the Renaissance, a more adventurous spirit came into the world, but at first in philosophy, it only took the form of following Greeks other than Aristotle, and more especially Plato. It is only with Bacon and Galileo that the inductive method arrived at due recognition: with Bacon as a programme which was largely faulty, but with Galileo as something which actually led to brilliant results, namely, the foundation of modern mathematical physics. Unfortunately, when the pedants got hold of induction, they set to work to make it as tame and scholastic as deduction had been. They searched for a way of making it always lead to true results, and in so doing robbed it of its adventurous character. Hume turned upon them with sceptical arguments, proving quite conclusively that if an induction is worth making it may be wrong. Thereupon Kant deluged the philosophic world with muddle and mystery, from which it is only now beginning to emerge. Kant has the reputation of being the greatest of modern philosophers, but to my mind he was a mere misfortune.
Induction, as it appears in the text-books, consists, roughly speaking, in the inference that, because A and B have been found often together and never apart, therefore they are probably always together, and either may be taken as a sign of the other. I do not wish, at this stage, to examine the logical justification of this form of argumentation; for the present, I am considering it as a practice, which we can observe in the habits of men and animals.
As a practice, induction is nothing but our old friend, the law of conditioned reflexes or of association. A child touches a knob that gives him an electric shock; after that, he avoids touching the knob. If he is old enough to speak he may state that the knob hurts when it is touched; he has made an induction based on a single instance. But the induction will exist as a bodily habit even if he is too young to speak, and it occurs equally among animals, provided they are not too low in the scale. The theories of induction in logic are what Freudians call a “rationalisation”; that is to say, they consist of reasons invented afterwards to prove that what we have been doing is sensible. It does not follow that they are bad reasons; in view of the fact that we and our ancestors have managed to exist since the origin of life, our behaviour and theirs must have been fairly sensible, even if we and they were unable to prove that it was. This, however, is not the point that concerns us at present. What concerns us at present is the fact that verbal induction is a late development of induction in behaviour, which is nothing more or less than the principle of “learned reactions”.
This principle, as the reader will remember, states that, if a certain event calls out a certain response, and if another event is experienced just before it, or at the same moment, in time that other event will tend to call out the response which, originally, only the first event would call out. This applies both to muscles and to glands; it is because it applies to glands that words are capable of causing emotions. Moreover, we cannot set limits to the length of the chain of associations that may be established. If you hold an infant’s limbs, you call out a rage reaction; this appears to be an “unlearned reaction”. If you, and no one else, repeatedly hold an infant’s limbs, the mere sight of you will call out a rage reaction after a time. When the infant learns to talk your name may have the same effect. If, later, he learns that you are an optician, he may come to hate all opticians; this may lead him to hate Spinoza because he made spectacles, and thence he may come to hate metaphysicians and Jews. For doing so he will no doubt have the most admirable reasons, which will seem to him to be his real ones; he will never suspect the process of conditioning by which he has in fact arrived at his enthusiasm for the Ku Klux Klan. This is an example of conditioning in the emotional sphere; but it is rather in the muscular sphere that we must seek the origin of the practice of induction.