We have seen that the great border-land, or _terra media_, lying between particular ideas and general ideas has been strangely neglected by psychologists, and we may now be prepared to find that a careful exploration of this border-land is a matter of the highest importance for the purposes of our inquiry. I will, therefore, devote the present chapter to a full consideration of what I have termed generic ideas, or recepts. It has already been remarked that, in order to form any of these generic ideas, the mind does not require to combine _intentionally_ the particular ideas which go to construct it: a recept differs from a concept in that it is _received_, not _conceived_. The percepts out of which a recept is composed are of so comparatively _simple_ a character, are so frequently _repeated_ in observation, and present among themselves resemblances or analogies so _obvious_, that the mental images of them run together, as it were, spontaneously, or in accordance with the primary laws of merely sensuous association, without requiring any conscious act of comparison. This is a truth which has been noticed by several previous writers. For instance, I have in this connection already quoted a passage from M. Taine, and, if necessary, could quote another, wherein he very aptly likens what I have called recepts to the unelaborated ore out of which the metal of a concept is afterwards smelted. And still more to the purpose is the following passage, which I take from Mr. Sully:—“The more _concrete_ concepts, or _generic_ images, are formed to a large extent by a _passive_ process of _assimilation_. The likeness among dogs, for example, is so great and striking that when a child, already familiar with one of these animals, sees a second, he recognizes it as identical with the first in certain obvious respects. The representation of the first combines with the representation of the second, bringing into distinct relief the common dog features, more particularly the canine form. In this way the images of different dogs come to overlap, so to speak, giving rise to a typical image of dog. Here there is very little of _active_ direction of the mind from one thing to another in order to discover where the resemblance lies: _the resemblance forces itself upon the mind_. When, however, the resemblance is less striking, as in the case of more abstract concepts, a _distinct operation of active comparison is involved_.”[26]