These comprehensive concepts, or _universals_, as some psychologists term them, the mind, having pieced together from experience and memory, holds as independent realities, not primarily belonging to _this_ or _that_, but lending themselves to this or that. For example: My mind says "white," and sees white in some object. But I see the white only because my mind has a quality concept, _whiteness_. This outside object corresponds to my concept. I recognize the likeness and call it "white." I speak of goodness, or purity, of benevolence; or of fulness, emptiness, scantiness. There is no object or quality in the outside world I can say is goodness, or fulness. But I do see things in the external world through my ideas of goodness or fulness that correspond to these ideas. They have some of the qualities the ideas embrace; and so I point them out and say, "This represents purity; that, impurity"; or, "This is full, that is empty." One satisfies my concept of purity, while the other does not. One fulfils my concept of fulness; the other does not. And because we can never point out any one quality in the outside world and say "This is purity, and all of purity; this is goodness; or this good plus this good plus this makes all of goodness"; because of this impossibility we speak of these concepts as having reality somewhere. They are _absolutes_, _universals_, _abstract quality concepts_--the unfound all of which the things we call pure and good are but the part. _Apperception_ is the process of comparing the new with all that is in the mind, and of classifying it by its likeness to something already there. With an abstract idea of an object in mind we very deftly, through the use of memory and constructive imagination, deduce the whole from the part recognized as familiar. Example: In walking through the field, along the bank of the brook, I glimpse under the low-hanging branches of the weeping willow a restlessly moving hoof. I see a certain kind of hoof and only that. Or I hear a lowing sound. And I say "cow." I have not seen a cow, but only a part which tells me a cow is there; for all the cows I ever saw had hoofs of that general description, and so it fits into my concept _cow_, and into no others. Or I have heard cows, only, give that lowing sound before. From my perception, then, of hoof or sound I apperceive _cow_. Memory relates that hoof or that lowing sound to a certain kind of animal known in the past; and constructive imagination draws in all the rest of the picture that belongs with it.