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.