Page:Popular Science Monthly Volume 30.djvu/241

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PHYSIOLOGY OF ATTENTION AND VOLITION.
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attempting to reform education by "devising courses," by finding out new things, by contesting the supremacy of this or that branch of knowledge, does it not seem wiser to insist upon right teaching? Subjects as doleful to the common student-mind as Latin grammar, Greek grammar, formal logic, psychology, and ethics, have been made "to revolutionize" the whole state of being for many a pupil, and this by right teaching. All knowledge is worthy—worthy the best of human endeavor, both to secure and to communicate. Let us, then, pass from this as from a matter not needful longer to be discussed, and demand true teaching.

THE PHYSIOLOGY OF ATTENTION AND VOLITION.

By JAMES CAPPIE, M. D.

"GIVE me a fulcrum," cried the ancient sage—"give me a fulcrum, and I shall move the world." "Grant me a few postulates," says the modern reasoner, "and I shall read you the riddle of the universe." An unchallengeable postulate, however, is almost as difficult to find as a stable extra-terrestrial fulcrum. The scientific "spirit of the age" walks by sight and not by faith. It revels in facts. It numbers, and weighs, and measures; it catalogues and describes; it compares and classifies. To make progress among the secrets of Nature its highway is experiment, and its watchword is demonstration. For any interpretation of a natural phenomenon it demands proofs that can appeal to the senses, and it looks with wholesome suspicion, if not contempt, on mere "arm-chair" speculation.

The marvelous success in advancing knowledge, and in gaining power over the forces of Nature that has resulted from its use, is convincing evidence that the scientific method of interrogation is sound, and that it should always be adopted wherever possible. But it is not always possible to apply the method. The nearer we approach the region of subjective phenomena, the more difficult it becomes to test particular interpretations by an appeal to experiment. The galvanometer may reveal agitation in a sensory surface, but it tells nothing about sensation. The convolutions of a dog's brain may be tampered with, but he will not describe to us his feelings. Consciousness alone can discriminate the facts of consciousness; and the character, or succession, or relation of these can only be described in terms of meta-physic. Theories of physical relationship here must at first be tentative, and at the best they will require to be stated in very general terms. The argument must consist in the application of general principles; and, in choosing these, analogy balanced by common sense must be our guide. In drawing our conclusions, we may be satisfied if these can be held with some moderate degree of probability.

In attempting to gain a closer view of the somatic relations of mind,