or Sensations on the one hand, and Images or Ideas on the other; and does not hesitate to state that the latter are in some sense copies of the former.
This is a view which was of course not original with the elder Mill, but it was brought into prominence by him and was held by his followers without any thoroughly critical examination; and it is a view which is subscribed to, although somewhat hesitatingly, by many psychologists to this day. Hume in fact held that the difference referred to was based upon a mere difference of intensity: and Prof. James, when writing his larger Psychology, still clung to the same view,[1] although he acknowledged other, but for him less important, marks of difference.
Prof. G. F. Stout[2] indeed tells us that "we ought to hesitate before discarding a distinction generally accepted both by psychology and common sense. On the other hand, if we accept it, we must mean by 'vividness' something different from those degrees of sensible quality which may be equally present in the sensible quality as actually perceived and as mentally reproduced. What is this vividness? The answer seems to be contained in Hume's words. According to him the distinctive characteristic of percepts as compared with images is the force and liveliness with which they strike the mind. This 'striking the mind' is the essential point. At bottom the difference is a difference of quality, not of degree. Images do not strike the mind in the same way as percepts." Evidently we are here dealing with a phenomenon of attention and not with the distinction between presentation and representation which Stout speaks of as a 'difference of quality'.
In any event it seems clear that we must abandon the view that the difference between the two is merely a difference of intensity; a view which, in the opinion of Dr. James Ward, was effectually disposed of by Reid and by Lotze, and which Dr. Ward[3] has himself certainly shown to be untenable. As Sully[4] says, "it is evident that this" (difference of intensity) "is not the whole of it; otherwise we should confuse weak and indistinct impressions (e.g., those of faint sounds, or of indistinctly seen objects) with images"; and this we do not find ourselves doing.
It is not difficult to understand how this notion that
