Page:Popular Science Monthly Volume 36.djvu/652

634 reading, we cast the eye rapidly down the page and, although we do not see one half the words, or a fraction of the letters, yet we catch the sense. If it happens to be a letter from a well-known friend, we read also, as we say, between the lines. Really we read out of our own heads.

The subjective or a priori factor is simplest, therefore, when, as in the cases given, it is merely the class notion, horse or sugar; it is most complex when it represents, for instance, a whole system of astronomy, as when, in a falling body, there is apperceived a law of gravitation. But, simple or complex, it follows, first, that unless there be an inner group of ideas to which the object may in some way be referred, knowledge of it is impossible; and, secondly, that the character of the resulting knowledge depends upon the character of the inner group of ideas. You and I, therefore, see everything to some extent differently. You see things from the standpoint of your previously acquired groups of ideas; I from mine. Strictly, no two persons can see the same thing in the same way, for it can never happen that two persons have precisely the same groups of ideas relating to any subject. These depend on our past experience, on our education, on the beliefs of our times, on our various sects or parties, on our pet theories, our interests, and our desires. Here is a simple illustration. Suppose an artist and an engineer, standing side by side overlooking a tract of country. What they perceive is the same; what they apperceive is wholly different. To the engineer the country presents itself as a possible line for a railroad, with here advantageous grades and there economic bridges. Before the artist is spread out a landscape, with light and shade and harmony of colors. Suppose, again, a plot of level ground in the suburbs of a city. A college student riding by apperceives it as a possible ball-ground; a young girl, as a tennis-court; a speculator, as an addition for town lots; an undertaker, perhaps, as a possible site for a cemetery.

In the primary laws of knowing, above stated, we discover the ground principles of the psychology of prejudice. The results may be summed up in the form of two laws:

 1. We see only so much of the world as we have apperceptive organs for seeing. 2. We see things not as they are but as we are—that is, we see the world not as it is, but as molded by the individual peculiarities of our minds.

Applications of the first law I shall state briefly; of the second, more in detail. The eye is limited by its structure to the reception of ethereal vibrations between the colors red and violet. The ear converts into sound only air-vibrations of a limited rapidity. Just so the mind, in its reception of knowledge, is