So long as we stick to examples, all this seems straightforward; only it is not easy to decide whether mind is activity, or whether these various activities are activities of mind. On the whole, common sense leans to the latter view: the activities are manifestations of mind. Mind itself is then something immaterial, lying behind the manifestations. What sort of thing? Apparently, another human being, =an inner man that dwells within the outer man=, an insubstantial mannikin living inside the head. Does that sound absurd? But it did not seem absurd just now to read that we ascribe to mind the same sort of voluntary and purposeful activity that we ascribe to our fellow-men; and how could we do that unless mind were something like a human being? This inner man appears, in fact, to be the mind of common sense; the inner man thinks, reflects, remembers, desires; he is influenced by the outer man, becoming gloomy and morose when his host cannot digest; and he influences the outer man, who sheds tears when his inmate is grieved. A curious view, when we write it out and think of it in cold logic; but a view that we should understand if we traced the growth of common sense from its first beginnings; and a view of highly respectable antiquity. Very ancient superstitions are connected with the man who is seen in the eye; the Egyptian _ka_ or spirit-double is a smaller copy of the outer man; Greek vase-paintings show the human soul as a tiny human being; primitive thought has from time immemorial explained, and the modern savage still explains, the life and motion of man, or his repose in sleep and death, by the presence or absence of the little creature normally at work within him. Yet however natural a view like this may be, science can make nothing of it. For one thing, it merely pushes the problem a step further back. The inner man acts on the outer man and is acted on by him; but who or what gives the inner man, in his turn, the power to influence and to be influenced? We must suppose an endless nest of mannikins. That and other such arguments apart, however, the view is non-scientific because it offers an interpretation and not a description of mind. _The mind with which psychology deals must be a mind that is describable in terms of observed fact_; otherwise it cannot form the subject-matter of a science. So we must start afresh, and ask what mind is, when mind is looked at =from the scientific point of view=. You will better understand the answer to this question when you have worked through the book. The answer will then have been given in the concrete and particular; now it can be given only in the abstract and general. Remember that it is given, nevertheless, in terms of work done and results obtained; it is not an answer that the psychologist makes up beforehand, but one that he himself has been led to in the course of his attempt to work scientifically upon mind. In brief it is this.