A theory, no matter in what department of investigation it may be found, whether relating to matter or mind, is strong in proportion to the number of facts which it will bring into line, harmonize and reduce to system. It is that which makes the Nebular Theory of the formation of the planetary system so wonderfully strong; it harmonizes and reduces to system so many known but otherwise unrelated and unsystematized facts; and it is easier to find excuses or form minor theories to account for isolated and apparently erratic facts, like the retrograde motions of the satellites of Uranus and Neptune, than to give up a theory, at once so grand in itself and at the same time harmonizing so many important astronomical phenomena. The same is true of the undulatory theory of light, and again of the theory of evolution, which forty years ago was looked upon as a flimsy hypothesis, but which is now universally accepted as an established truth. Some of the facts are still unclassified and unexplained, yet it so harmonizes in general the facts of the visible world, that instead of a mass of disjointed and heterogeneous objects and phenomena, such as men beheld in nature only a hundred years ago, the arbitrary work of a blind chance or a capricious Creator, we now behold a beautiful and orderly sequence, progression, and unfolding of the natural world according to laws which command our admiration and stimulate our reverence. Apart from recent studies, exactly the same condition of chaos and confusion exists regarding psychical phenomena as existed concerning the facts in the physical world only a hundred years ago. Nor is it likening great things to small when we compare the nebular hypothesis, or the theory of evolution, conceptions which have educated an age and vastly enlarged the boundary of human thought, to the theory of telepathy and the fact and power of the subliminal self. For if it was important that men should know the laws governing inanimate matter, to comprehend the orbits and motions of the planets; if it developed the understanding to contemplate the grandeur of their movements, the vast spaces which they traverse, and the wonderful speed with which they accomplish their various journeys--if such knowledge has enlarged the capacity of men's minds, given them truer notions of the magnitude of the universe, and grander conceptions of nature and the infinite power and intelligence which pervades and is exhibited in it, is it not equally important and equally improving and practical to study the subtler forces which pervade living organisms, the still finer laws and adjustments which govern the action of mind?