Page:Philosophical Review Volume 9.djvu/569

553 than to show that the balance of probabilities is in its favor. When we have shown that, we have made the doctrine worthy of credence, we are entirely justified in accepting it as truth and adopting it as a rule of conduct" (p. 80).

The remaining chapters of the book are detailed illustrations of the positions already sketched. As a whole the book is not timely. It proceeds with apparent disregard of modern epistemology, and contains no thorough analysis of the foundations of science.

This volume is the last of a series of three designed "to demonstrate the unity of substance by means of positive facts to the exclusion of all a priori argument." The first volume of the series was entitled La matière et l'energie, the second La vie et l'ame. The first book of this volume gives a resume of the contents of the two earlier works, the outcome of which is that the soul is the function of the brain. It is not a simple unity but a resultant. Just as white light, so apparently simple, is shown by the prism to be the resultant of seven colors, so the unity of the soul is shown by facts both normal and pathological to be a resultant. The soul of man is of the same nature as that of the animal. The difference is only one of degree. Matter and energy alone, however, do not account for the phenomena of life. The theory of evolution suffices to reduce derived forms to anterior types. Science is silent as to these original types. "It follows that the existence of form implies the existence of a first cause." And again, since science shows that all life comes from the germ, "it follows that the origin of life on the terrestrial globe implies the existence of a first cause" (p. 86). Biology has disproved spontaneous generation. Chemistry has disproved the existence of vital forces, and cerebral physiology the existence of individual souls as physical substances. The terms of the metaphysical problem therefore are reduced to a first cause and matter-energy. The problem is how are these two related.

Book second on "Final Causes" maintains that there is a plan and directing idea at the origin of primordial types, but no finality is manifested in the relations of the several groups of beings to one another. "The egg of the hen is not made to serve as food for man, but to produce a hen." Each being has its finality in itself, not outside of itself. There is "internal finality " but no "external finality." Books third and fourth take up more than half the volume, and discuss the plan of the creation of the animal kingdom and vegetable kingdom respectively. The outcome of this discussion is that the theory of gradual perfection is proved false by the facts. Such facts as the late appearance of lower forms, the existence of parasites which must