related to the realm of the perishable and changeable is a problem on which Aristotle has been often (and with some reason) believed to be obscure, if not even inconsistent(21).
In these divergent elements which come to the fore in Aristotle’s treatment we have the appearance of a radical difference of conception and purpose as to psychology. He himself does a good deal to keep them both in view. But it is evident that here already we have the contrast between a purely physical or (in the narrower sense) “scientific” psychology, empirical and realistic in treatment, and a more philosophical—what in certain quarters would be called a speculative or metaphysical—conception of the problem. There is also in Aristotle the antithesis of a popular or superficial, and an accurate or analytic, psychology. The former is of a certain use in dealing, say, with questions of practical ethics and education: the latter is of more strictly scientific interest. Both of these distinctions—that between a speculative and an empirical, and that between a scientific and a popular treatment—affect the subsequent history of the study. Psychology is sometimes understood to mean the results of casual observation of our own minds by what is termed introspection, and by the interpretation of what we may observe in others. Such observations are in the first place carried on under the guidance of distinctions or points of view supplied by the names in common use. We interrogate our own consciousness as to what facts or relations of facts correspond to the terms of our national language. Or we attempt—what is really an inexhaustible quest—to get definite divisions between them, and clear-cut definitions. Inquiries like these which start from popular distinctions fall a long way short of science: and the inquirer will find that accidental and essential properties are given in the same handful of conclusions. Yet there is always much value in these attempts to get our minds cleared: and it is indispensable for all inquiries that all alleged or reported facts of mind should be realised and reproduced in our own mental experience. And this is especially the case in psychology, just because here we cannot get the object outside us, we cannot get or make a diagram, and unless we give it reality by re-constructing it,—by re-interrogating our own experience, our knowledge of it will be but wooden and mechanical. And the term introspection need not be too seriously taken: it means much more than watching passively an internal drama; and is quite as well describable as mental projection, setting out what was within, and so as it were hidden and involved, before ourselves in the field of mental vision. Here, as always, the essential point is to get ourselves well out of the way of the object observed, and to stand, figuratively speaking, quite on one side.