PRESENTATION AND REPRESENTATION. 57 tion ; and this notwithstanding the fact that the differences between successive presentations in the same person may altogether escape our observation. Sec. 3. If however we accept this view without further consideration we overlook one very important fact of ex- perience which on its face seems to stand in opposition to our position. We constantly speak, not only in every-day conversation, but also in careful philosophical discussion, of the existence of representations ; and we use this term as though it were a matter of common agreement that the mental states referred to are not in each case new presentations, but are duplica- tions of former presentations of which we have an unchanged record a record with which we compare the so-called repre- sentations, and with which we in a measure identify them. Nor is this merely a matter of the careless use of words. It is clear that the founders and earlier expounders of the Associationist school tacitly assumed such permanence of presentations ; and that the Herbartians did so explicitly. If our contentions are valid we are then surely called upon to explain the nature of these so-called representations as a certain type of new and unique presentations. The common assumption of psychologists, the validity of which is thus questioned, is au fond the same as one which is involved in the view of the associationists who held that images and ideas are of a sensational type, being copies in some sense of real sensational experiences, or developments of such copies. This being the case it will be well to begin our study of the problem before us with a consideration of the general nature of images and ideas as these are dis- tinguished from sensational impressions. II. OF PRIMARY AND SECONDARY PRESENTATIONS. Sec. 4. " The sensations which we have through the medium of the senses exist only by the presence of the object and cease upon its absence." " When our sensations cease, by the absence of their objects something remains," "It is not the sensation, but something different from the sensation, yet more like the sensation than anything else can be ; so like that you call it a copy, an image, of the sensation, sometimes a representation or trace of the sensa- tion." " Another name for this is Idea." With these words James Mill opens the second chapter of his Analysis, thus clearly presenting the broad distinction between Impressions