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.