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Page:Popular Science Monthly Volume 72.djvu/470

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POPULAR SCIENCE MONTHLY

tedious, and would demand a greater amount of space than this magazine could be expected to furnish. The nature of the objections to the article can, however, be made clear without so comprehensive and minute an examination.

Let us, in the first place, take a single one of the tests, that relating to the size of the moon:

My next question did not refer to immediate perception, but to a memory image so vividly at every one's disposal that I assumed a right to substitute it directly for a perception. I asked my men to compare the size of the full moon to that of some object held in the hand at arm's length. I explained the question carefully, and said that they were to describe an object just large enough, when seen at arm's length, to cover the whole full moon.

The answers ranged from a carriage-wheel to a pea; and on this result Professor Münsterberg makes a number of interesting comments. "To the surprise of my readers, perhaps," he says, "it may be added that the only man who was right was the one who compared it to a pea. It is most probable that the results would not have been different if I had asked the question on a moonlight night with the full moon overhead. The substitution of the memory image for the immediate perception can hardly have impaired the correctness of the judgments. If in any court the size of a distant object were to be given by witnesses, and one man declared it as large as a pea and the second as large as a lemon-pie and the third ten feet in diameter, it would hardly be fair to form an objective judgment till the psychologist had found out what kind of a mind was producing that estimate." And elsewhere he refers to the fact that his students do not know "whether the moon is small as a pea or large as a man."

Now, this experiment, damaging as Professor Münsterberg considers it, has, in point of fact, no bearing whatever upon the perceptive powers of his students. If they understood perfectly what his question meant, and shaped their answers accordingly, those answers were the outcome of some kind of conscious mental calculation or experimentation (unless, indeed, we suppose that some of the students, for example the one with the pea, had made the explicit experiment of the obscuration of the moon by an object held at arm's length, and remembered the result). There is absolutely nothing in our direct perception of the moon to give us any idea of the angle it subtends, or of the size of an object which, held at arm's length, would "just cover it." Professor Münsterberg is, indeed, in this dilemma: either he wants to know what the intuitive feeling of a given man is as to the apparent size of the moon when he looks up at it, or he wants to know just what he explicitly declared—what object, held at arm's length, would cover it from the eye (i. e., one eye). If he means the former, the intuitive feeling, each person is the final arbiter of the question—he is either lying or telling the truth; the moon either does or does not seem to