Let it be granted, for argument’s sake, that trickery is possible. Let it be admitted, as a matter of fact, that many mediums have been detected and exposed in various instances of imposture. This shows merely that some alleged materialisations are not genuine; it does not prove that no materialisation ever takes place. Here, also, the sitter must judge for himself. Where it is possible to adopt both a normal and a supernormal explanation of any observed manifestation the rules of scientific enquiry impose upon us the obligation of postulating a “natural” cause in preference to assuming that some “supernatural” power is in operation; we are bound, for example, in cases admitting of trickery, to hold that the medium is a cheat rather than to infer the intervention of any spirit. But when a normal explanation is not possible, or so highly improbable as to be outside the confines of good sense, we act foolishly if we insist upon declining to recognise a patent fact merely because it does not fit in with our preconceived opinions. The same remark applies, _mutatis mutandis_, to many of the “normal explanations” in themselves. It is, for example, said sometimes that the voices heard in the course of dark sittings are produced ventriloquially by the medium. This leaves out of view the consideration that ventriloquy is in itself an illusion depending upon the sense of sight as well as upon that of hearing. No ventriloquist, however clever, can produce the impression of there being a sound emanating from some specific locality when the hearer is in the dark; a fact that is evident to any person who tries the experiment of shutting his eyes when at a ventriloquial entertainment. And if we reflect that in a materialisation _séance_ several distinct voices are often heard simultaneously, the explanation of the medium being a ventriloquist is seen to be ludicrously inadequate. The “normal” theory does not fare any better in suggesting that the medium manages to vacate his chair in the darkness and to pick up the trumpet or the tambourine, etc., from which he forthwith proceeds to extract some sounds. This might be feasible in the case of a single instrument in a single locality; but it often happens that several instruments of various kinds are being played simultaneously and are heard in different parts of the room at the same time. And when it is remembered that the sitting where such facts occur may, and does frequently, take place in a sitter’s own house, where the medium has not been able to make any preparations and where no confederate is available, the futility of the “natural” way of accounting for the manifestations becomes still further evident. So, after all, we come round once more to the recommendation that the sitter should not interfere, should merely observe, should keep an open mind and should be guided by facts quite irrespectively of whether the facts be normal or supernormal. CHAPTER VIII “SPIRITUALISM” AND “RATIONALISM”