It remains to point out that the embryological doctrines of Maupertuis were intimately connected with certain metaphysical conceptions, of a type that has often since shown itself to be peculiarly congenial to minds trained in biology. The 'Système de la Nature' is primarily an exposition and a defense of the theory that all matter possesses some sort of consciousness—a 'monism' similar to that of which Haeckel is the contemporary prophet. A purely mechanistic materialism, such as the atomism of the Epicureans, or the crude notions which La Mettrie had recently put forward, seemed to Maupertuis an evident absurdity; 'in order to overthrow such a system,' he writes, 'one need do no more than ask those who hold it how it would be possible for atoms without intelligence to produce an intelligence.' Mere mechanism appeared as little capable of explaining the phenomena of organic life, as it was of explaining the phenomena of consciousness; especially manifest, Maupertuis thought, is the inadequacy of purely mechanical causes to account for the processes which he conceived to be involved in the formation of the embryo. "A blind attraction uniformly distributed throughout all particles of matter can not serve to explain how these particles arrange themselves to form even the simplest of organized bodies. If they all have the same tendency, the same power, to unite with one another, why is it that certain elements go to form the eye, certain others to form the ear, etc.? Why this marvelous arrangement? Why is it that the various elements are not united pell-mell?" The combination of material particles to form a living organism seemed to imply a principle of selection, a species of elective affinity between the particles, which could not be reduced to physical or chemical categories; and the singular fact of heredity, the transmission of qualitative similarities from one organism to another through whatever minute bodies serve as the vehicles of heredity, seemed to imply the possession by those bodies of something which could only be conceived under the analogy of conscious memory. It is necessary, then, to attribute to each particle of matter the possession of some rudimentary forms of sentiency, memory and volition. (Si l'on vent dire sur cela quelque chose qu'on conçoive, quoiqu'encore on ne le conçoive que sur quelque analogie, il faut avoir recours a quelque principe d'intelligence, a quelque chose de semblable a ce que nous appellons désir, aversion, mémoire). Maupertuis does not forget the radical difficulty which has been urged against the identification of the res cogitans and the res extensa ever since Descartes—the difficulty, namely, that the attributes of consciousness and extension have nothing in common, and that neither can thought be conceived as ex-
of generation appeared earlier than that of Maupertuis, which is not the case. The general conception of the 'evolution movement' and of the relative importance of its several eighteenth century representatives, in Professor Oshorn's book, seems to the present writer decidedly misleading.
