possession by man of an immaterial soul. Metaphysics is, from the nature of the case, the ultimate court of appeal in such a question; the crude assertion that scientists reject the soul because the microscope, the skiograph, or the scalpel has never revealed it, is one of the choice expressions invented by theologians, who never read scientists for the satisfaction of their people, whom they will not allow to read them. Neither literally nor metaphorically is it a correct statement of the case. The truth is that there are two forces at work in modern physical science, which proceed satisfactorily until we come to human psychology, and which the scientist is naturally loth to relinquish at this point until the gravest possible reasons are shown for respecting the immunity claimed for it. On the one hand we have this law of unity or parsimony, the tendency to restrict as far as possible the number of ultimate factors of the universe; this is a natural protest of a sounder scientific spirit against the reckless multiplication of forces and principles of less enlightened ages, when all different sets of phenomena were attributed at once to radically distinct principles, and supposed to be explained. On the other hand there is the law of evolution—the most brilliant discovery of the century—which has shed so marvellous a light on the past history of the world, and which now only encounters serious opposition when it deals with the origin of human intelligence. To show that a mechanical or monistic view of the universe and an acceptance of evolution cannot include man, it is necessary to point to certain of his characteristics, which reveal the presence in him of a new and specifically distinct principle; until that is done the claims which evolution and mechanicism derive from their already universal application cannot be set aside. Difficulties in their application there will be; but difficulties, as theologians so loudly protest in other matters, are not objections.
The philosophy which I taught was, of course, essentially dualistic: it takes a middle course between Materialism and Berkleian Idealism. Moreover, it teaches that the human soul is not an isolated spirit, as in Plato’s and Descartes’s teaching, in absolute contrast to the rest of the universe; the immaterial world is interwoven much more intimately with the material. The problem, therefore, on which my mind was exercised, and in the solution of which I came to my present attitude, was to establish clearly the frontiers of the immaterial world, where we could confidently face the rising tide of scientific naturalism, and say: “Here shall thy proud waves break.” For I thought there was no sadder sight in the history of the century than the retreat of our apologists from the untenable positions they successively occupied. Not only was this the case in Scripture and in history, but it was conspicuously true in those provinces of philosophy which they once peopled with immaterial principles. Whatever may be said of conser-
