be returned to this question. We may suppose the one answer to be that our knowledge is wholly, or almost wholly, due to the mind itself; that none, or, at any rate, very few of the ingredients of cognition are derived from foreign sources. And conversely we may suppose the other answer to be, that all, or nearly all, the elements of cognition are derived from foreign sources, and that none, or scarcely any, of them are native products of the mind. I have laid down these two answers in an extreme form, in order that you may the better understand them. The one solution is, that the mind originates all, or nearly all, its knowledge from within, and derives almost nothing ab extra. The other solution is, that the mind derives all, or nearly all, its knowledge, ab extra, and originates scarcely anything from within.
4. These two solutions, which I have advanced by way of supposition, have found plenty of upholders, as we know from the history of philosophy—upholders not perhaps in quite the extreme forms in which I have expressed them, but in forms certainly approaching very near to these extremes. Indeed these two answers may be said to divide the psychological world into the two most general divisions which it presents. The party which tends towards the one extreme consists of those who advocate the psychology of innate ideas. The party which approaches, and I think we may say sometimes reaches, the other extreme, consists of those who advocate
