matter; and the other, because he can when he will reflect upon his knowledge, provided there is no external impediment to his doing so. It is this one only, however, when actually reflecting upon his knowledge, being in activity, and fully acquainted with some one subject, as A. for instance, who is to be accounted learned in reality. Both those first men, in fact, are learned in potentiality; but the one is so from having been modified by learning, and undergone frequent changes from one habit to an opposite one; and the other is so from possessing sensibility or rudimentary learning, and being able, although in a different manner, to pass from inertia to activity.
But the term impression is not absolute in signification, as sometimes it implies a kind of destruction by a contrary, and sometimes it signifies rather preservation of something being in potentiality by something which is in reality and like, in the relation that potentiality bears to reality. Thus, the possession of knowledge implies the power of reflecting upon it, and this either is not change, being but an increase of knowledge and a step towards its completion, or it is change of a different kind. It is not correct, therefore, to say that an individual, when thinking, is undergoing change, any more than that a builder, when employed in building, is undergoing change; so that the process by which an individual passes, as to his thinking and reflecting faculties, from potentiality to
