In Locke's famous countryman, Isaac Newton (1642-1727),[1] 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 discard 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 great principle, "Abandon substantial forms and occult qualities and reduce natural phenomena to mathematical laws," before he could crown the discoveries of Galileo and Kepler with his own. For this successful union of Bacon's experimental induction with the mathematical deduction of Descartes, this combination of the analytic and the synthetic methods, which was shown in the demand for, and the establishment of, mathematically formulated natural laws, presupposes that nature is deprived of all inner life [2] and all qualitative distinctions, that all that exists is compounded of uniformly acting parts, and that all that takes place is conceived as motion. With this Hobbes's programme of a mechanical science of nature is fulfilled. The heavens and the earth are made subject to the same law of gravitation. How far Newton himself adhered to the narrow meaning of mechanism (motion from pressure and impulse), is evident from the fact that, though he is often honored as the creator of the dynamical view of nature, he rejected _actio in distans_ as absurd, and deemed it indispensable to assume some "cause" of gravity (consisting, probably, in the impact of imponderable material particles). It was his disciples who first ventured to proclaim gravity as the universal force of matter, as the "primary quality of all bodies" (so Roger Cotes in the preface to the second edition of the _Principia_, 1713). [Footnote 1: 1669-95 professor of mathematics in Cambridge, later resident in London; 1672, member, and, 1703, president of the Royal Society. Chief work, _Philosophic Naturalis Principia Mathematica_, 1687. _Works_, 1779 _seq_. On Newton cf. K. Snell, 1843; Durdik, _Leibniz und Newton_, 1869; Lange, _History of Materialism_, vol. i. p. 306 _seq_.] [Footnote 2: That the mathematical view of nature, since it leaves room for quantitative distinctions alone, is equivalent to an examination of nature had been clearly recognized by Poiret. As he significantly remarked: The principles of the Cartesian physics relate merely to the "cadaver" of nature _(Erud_., p. 260).]