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.
Again, we may apperceive an object or quality from our recognition of something which in our experience has been associated, under those particular circumstances, with only that object or quality. I see smoke on the ocean’s far horizon, and I decide instantly, “a steamer.” I have not perceived any steamer, but only something that “goes with it,” as it were. I see the ship with my mind, not with my eyes; for I know that a cloud of smoke out there always has, in my past experience, represented just that. I compare the newly appearing stimulus—smoke in that particular location—with all that is associated with it in my mind, and classify it with the known. I apperceive “steamer.”
In apperception, then, we construct from the known actually perceived by the senses, the unknown. How does the child realize that the moving speck on the distant hillside is his father? There is nothing to indicate it except that it is black and moves in this direction. But experience tells Johnny that father comes home that way just about this time. Moreover, it says that father looks so when at that distance. When Johnny is as sure it is his father as if he could see his face close beside him he has apperceived him. The speck on the hill is the newly arriving stimulus. Johnny compares it with what corresponds to it in his mind’s experience and proclaims, as a fact, that he sees his father.
Reason is the mind’s comparison and grouping of concepts to form judgments, and its association of judgments to form new judgments.
Example: My concept man includes the eventual certainty of his death. My concept mortal means “subject to death.” Therefore my judgment is, “Man is mortal.” Reason has compared the concepts and found that the second includes the first.
Judgment is the mind’s decision arrived at through comparing concepts or other judgments.
Example: Man is mortal is my decision after comparing the concepts man and mortal and finding that the latter really includes the former. Judgment at the same time says that “Mortals are men,” is not a true conclusion. For in this case the first concept is not all included in the second. Mortals are all life that is subject to death.
We may assume personal consciousness even as we recognize an individual body. Psychology does not deal with any awareness separated from a person. It knows no central mind of which you partake or I partake, and which is the same for us both. A universal consciousness would simply mean one which is the sum of yours and mine and everybody’s who lives today, or who has ever lived. So by personal consciousness the psychologist means his consciousness, or yours, or mine. But they can never be the same; for mine is determined by my entire past and by how things and facts and qualities affect me; and yours, by your past, and by things and facts and qualities, and by how they affect you.