ledging this risk, a few sentences must be given to it. Negatively, it is a vigorous protest against the unwarranted advocacy of the purely mechanical and chemical categories as complete and adequate media for the explanation and appreciation of vital phenomena. It is also a protest, eminently sane in its contentions, against the loose and inaccurate extensions of analogy from one stage to another of life processes, save when an examination of each series concerned may have shown the analogy just. Positively, the theory assigns to "agenetic science " the securing of exact quantitative formulæ descriptive of phenomena in convertible propositions. Thus, A = B, and B = A. In all truly genetic science, on the other hand, descriptive formulge are never reversible. The product of any genetic series at any stage of its development always contains something unique which was not previously in the series. The author says: "Genetically A = B, but it does not follow that B = A" (p. 303). Again, "that series of events only is truly genetic which can not be constructed before it has happened, and which cannot be exhausted by reading backwards after it has happened" (p. 311). "In the life processes there seems to be a real genetic series, an irreversible series. Each stage exhibits a new form of organization" (p. 330). From Mr. Baldwin's point of view, history as well as biology is a genetic science. One cannot employ exact science for prediction (even theoretically), but after historical events have occurred they should, according to our author, be capable of formulation in the terms of exact science.
So far as Mr. Baldwin is attempting to curb the overweening pride of the prophets of a physico-chemical philosophy of life, he will find sympathizers in plenty. Whether the method which he proposes can finally be accepted, it will hardly be possible to say until the doctrine is more fully developed. Take, for example, his expressions about reversibility. If the irreversibility of vital phenomena refers to the mere conceivability of a given order, then the contention is obviously false. If it refers to causal relations of any kind, then it is true of all series, inorganic as well as organic, and the distinction becomes useless. Mr. Baldwin will have to make his peace with Kant, Royce, and others for the liberties he takes—as I understand him—with irreversibility. Moreover, it is not clear in what sense a genetic series produces results which are unique in any way which is not equally true of inorganic processes. Surely the distinction here is not so obviously one of uniqueness in the product, as it is one resting upon the degree of our ability to control the producing factors. If we once know what the series of fission processes are by which a cell divides, we are just as
