CHAPTER V. ENGLISH PHILOSOPHY IN THE EIGHTEENTH CENTURY. Besides the theory of knowledge, which forms the cen^ tral doctrine in his system, Locke had discussed the remain* ing branches of philosophy, though in less detail, and, by his many-sided stimulation, had posited problems for the Illumination movement in England and in France. Now the several disciplines take different courses, but the after- influence of his powerful mind is felt on every hand. The development of deism from Toland on is under the direct influence of his "rational Christianity"; the ethics of Shaftesbury stands in polemic relation to his denial of everything innate; and while Berkeley and Hume are deducing the consequences of his theory of knowledge, Hartley derives the impulse to a new form of psychology from his chapter on the association of ideas. I. Natural Philosophy and Psychology. In Locke's famous countryman, Isaac Newton (1642- 1727),* the modern investigation of nature attains the level toward which it had striven, at first by wishes and demands, gradually, also, in knowledge and achievement, since the end of the mediaeval period. Mankind was not able to dis- card at a stroke its accustomed Aristotelian view of nature, which animated things with inner, spirit-like forces. A full century intervened between Telesius and Newton, the concept of natural law requiring so long a time to break out of its shell. A tremendous revolution in opinion had to be effected before Newton could calmly promulgate his
- 1669-95 professor of mathematics in Cambridge, later resident in London ;
1672, member, and, 1703, president of the Royal Society. Chief work, Philo- sophia Naturalis Principia Mathematica, 1687. IVor/^s, lyjq seq. On Newton cf. K. Snell, 1843 ; Durdik, Leibniz und Newton, 1869 ; Lange, History of Materialism, vol. i. p. 306 seq. 181
