In Theosophical literature, for instance, we are confronted with a scheme of things built up of such terms as "Astral Plane," "Etheric Double," "Causal Body," "Karma" and so forth. With all due deference to my Theosophical friends I submit that this is not scientific explanation and cannot be so unless its exponents are prepared to tell us what is the relation between the astral plane and the physical world, between the etheric double and the body as known to physiologists. Thus it is intellectually unsatisfying and little calculated to arouse the sympathetic interest of the strictly logical thinker. I do not mean to say that none of the words of the type quoted have any real significance. On the contrary I think it very probable that many of them have and that they do represent real parts of the actual scheme of things. The trouble is that they are only names; and to name a thing is not the same as to explain it. In common fairness I ought, however, to admit that in several passages Mr. Leadbeater--one of the best known Theosophical writers--makes a distinct effort to escape from this tendency and it has further been opined by a very eminent Occultist that the bulk of contemporary literature on the subject will be out of date in a few years. I am inclined to suspect that this failing was the cause he had in mind. I repeat that my primary quarrel is not with the accuracy or otherwise of the statements made. Every word of them may be perfectly correct, but so long as they are expressed in terms wholly unrelated to pre-existing concepts I must, _qua_ scientist, remain unconvinced. The third school which includes the Orthodox Theologians sometimes resembles the Occultists in the use of unintelligible terms but their chief weakness is their failure to recognise and to cater for the intellectual demand for coherent explanation. They never weary of insisting, quite rightly, on the paramount importance of Spiritual things, but no effort is made to show the continuity which must, in a sane Cosmos, exist between Matter and Spirit, or to state the "common factor," so to speak, which unites them as parts of a coherent whole. For myself I refuse to believe that no such common factor is discoverable. As Sir Oliver Lodge says, "I have learned to believe in intelligibility." This omission on the part of theologians did not so much matter in the days before Physical Science had attained to its present degree of development. Men knew so little about the material Universe that they experienced little difficulty in finding a place in it for Spirit and the Spiritual life. "Heaven" was conveniently represented as being somewhere "above" and "Hell" as somewhere "below." But now things have altered and we know quite a fair amount about the material world. Consequently the scientist demands--not unreasonably, I think--an explanation of "Spirit" which shall not conflict with the fundamental laws of continuity and causation.