II. EVOLUTION IN PHILOSOPHY (cont.)
French Writers of the 18th Century.Let us now pass to the French writers of last century. Here we are first struck by the results of advancing physical speculation in their being on the conception of the world. Careful attempts, based on new scientific truths, are made to explain the genesis of the world as a natural process. Maupertuis, who, together with Voltaire, introduce the new idea of the universe as based on Newtons discoveries, sought to account for the origin of organic things by the hypothesis of sentiment atoms. Buffon the naturalist speculated, not only on the structure and genesis of organic beings, but also on the course of formation of the earth and solar system, which he conceived after the analogy of the development of organic beings out of seed. Diderot, too, in his varied intellectual activity, found time to speculate on the genesis of sensation and thought out of a combination of matter endowed with an elementary kind of sentience. De la Mettrie worked out a materialistic doctrine of the origin of things, according to which sensation and consciousness are nothing but a development out of matter. He sought in (Lhomme-machine) to connect man in his original condition with the lower animals, and emphasized (Lhomme-plante) the essential unity of plan of all living things. Helvetius in his work on man, referred all differences between our species and the lower animals to certain peculiarities of organization, and so prepared the way for a conception of human development out of lower forms as a process of physical evolution. Charles Bonnet met the difficulty of the origin of conscious beings much in the same way as Leibnitz, by the supposition of eternal minute organic bodies to which are attached immortal souls. Yet though in this way opposing himself to the method of the modern doctrine of evolution, he aided the development of this doctrine by his view of the organic world as an ascending scale from the simple to the complex. Robinet, his treatise De la Nature, worked out the same conception of a graduation in organic existence, connecting this with a general view of nature as a progress from the lowest inorganic forms of matter up to man. The process is conceived as an infinite series of variations of specifications of one primitive and common type. Man is the chef daeuvre of nature, which the gradual progressive of beings was to have as its last term, and all lower creations are regarded as pre-conditions of mans existence, since nature "could only realize the human form by combination in all imaginable ways each of the traits which was to enter into it." The formative force in this process of evolution (or "metamorphosis") is conceived as an intellectual principle (idée genératrice). Robinet thus laid the foundation of that view of the world as whooly vital, and as a progressive unfolding of a spiritual formative principle, which was afterwards worked out by Schelling. It is to be added that Robinet adopted a thorough-going materialistic view of the dependence of mind on body, going even to the length of assigning special nerve-fibres sense. The system of Holbach seeks to provide a consistent materialistic view of the world and its processes. Mental operations are identified with physical movements, the three conditions of physical movement, inertia, attraction, and repulsion, being in the moral world self-love, love, and hate. He left open the question whether the capability of sensation belongs to all matter, or is confined to the combinations of certain materials. He looked on the actions of the individual organism and society as determined by the needs of self preservation. He conceived of man as a product of nature that had gradually developed itself from a low condition, though he relinquished the problem of the exact mode of his first genesis and advance as not soluble by data of experience. Holbach thus worked out the basis of a rigorously materialistic conception of evolution.
The question of human development which Holbach touched on was which occupied many minds both in and out of France during the past century, and more especially towards its close. The formations of this theory of history as an upward progress of man out of a barbaric and animal condition were laid by Vico in his celebrated work Principii di Scienza Nuova. In France the doctrine was represented by Turgot and Condorcet.
Of the English writers who discussed the question of mans development we have already spoken. The German speculation on the subject will be touched on presently.