Page:Popular Science Monthly Volume 50.djvu/533

Rh entity, akin in its nature to the physical substratum of light and electricity. The doctrine of the "astral body" belongs to this type. Or, the third entity may be conceived as akin to consciousness in its essential nature, although capable of separation from it. It may, for example, be identified with the life of sensation and sensuous desires which common sense discriminates from the "more spiritual" elements of thought, reason, and will.

If the third alternative be adopted, we must regard the principle which lies at the foundation of such phenomena as purely mental. The oldest form of this theory is the doctrine of possession, which ascribes all automatism to the agency of some adventitious mind, as that of a demon or spirit, entering into the body of the patient and assuming control, to the total or partial exclusion of its rightful owner.

In modern times the doctrine has assumed the form of "duplex personality." This theory maintains that in every man there are two minds, one known to us and one usually unknown. To the latter are ascribed all the phenomena of suggestibility and automatism, sometimes also telepathy, clairvoyance, and the like, and even the power of moving furniture, of objectifying and "materializing" its ideas, and of performing the other tricks which "mediums" ascribe to spirits.

A similar theory has been developed by Mr. F. W. H. Myers in a series of papers in the Proceedings of the Society for Psychical Research. Mr. Myers avoids the words soul, spirit, and the like in stating his theory, on account of their crude associations, but I shall in this popular sketch make use of these familiar words, even at the risk of misrepresenting him a little.

Mr. Myers agrees with the other representatives of the soul theory in acknowledging the existence of a spiritual entity of some sort, although he does not define it or attempt to fix its relation to matter. Its essence is consciousness; but—and this is the point characteristic of the theory—the consciousness of which my soul consists is not identical with what I call my consciousness. Every soul is the basis or ground of existence of many wholly distinct consciousnesses of which the consciousness I call mine is but one. It is not even the most important of them, although it also is not the least important. It has been evolved by a process of selection out of an infinity of possible elements solely on the ground of utility. Its function is the preservation of the body; those mental elements which were found most directly to