GERMAN PHILOSOPHY SINCE HEGEL Materialism.—Various influences combined to occasion a tend ency towards materialism about the middle of the 19th century. Idealism had on the whole sided definitely with conservatism in religion and politics. Hegel's dictum, "the real is rational," was readily exploited in a reactionary sense beyond anything that Hegel intended, conservative as he himself had been. The gen eration inspired by the revolutionary tendencies of 1848 resented this kind of idealism. Stimulated by the microscopic biology of Schwann (who showed the cell to be the unit of plant and animal organisms), by the chemical researches of Liebig, by Schleiden's rejection of vitalism, and by the physical experiments of Mayer, Joule, Colding and Helmholtz, which resulted in the discovery of the principle of conservation of energy, the scientific spirit of the age revolted against the idealists' indulgence in romantic speculation. Industrial progress, advance in the technical arts, and the consequent improvement in economic and material con ditions, also helped to stimulate special interest in things mate rial. And the doctrines of the French materialists of the 18th century, La Mettrie (1709-51), Holbach (1723-89) and Cabanis (1757-1808), were ready at hand to be taken up and developed. J. Moleschott (1822-93) described the whole cycle of life in terms of matter and energy. Matter conditions life, life condi tions thought, and thought conditions the will to improve life. Physical conditions are the main determinants of human destiny.
K. Vogt (1817-95) supplemented Moleschott's dictum, "no sulphur, no thought," with the statement that "thought is related to the brain in the same way as bile is to the liver." The same thing had been said already by Cabanis. Vogt did not pretend to know how exactly the brain does produce thought. L. BUchner was the most influential of this group, and his Force and Matter (1855) served for a considerable time as the source book of materialism. He identified force of every kind with movement, and regarded everything as the product of matter and motion which are distinguishable but not separable. He rejected vitalism, held that life is spontaneously generated out of matter under certain conditions, and that mental process is only "a radiation through the cells of the grey substance of the brain of a motion set up by external stimuli." H. Czolbe (1819-73) re jected everything supersensuous and all "transcendental non sense." But he maintained that the world cannot be derived from any one principle, such as BUchner's "force and matter," but only from a plurality of irreducible principles, including material atoms, organic forces, mental elements, etc., which between them constitute an harmonious and purposive natural system. Like the other materialists in this group, he was inspired by an enthusiasm for humanity and the amelioration of human conditions. (See