[223:1] PRELIMINARY NOTE.--By _naturalism_ is meant that system of philosophy which defines the universe in the terms of _natural science_. In its dogmatic phase, wherein it maintains that _being is corporeal_, it is called _materialism_. In its critical phase, wherein it makes the general assertion that the natural sciences constitute the only _possible knowledge_, whatever be the nature of reality itself, it is called _positivism_, _agnosticism_, or simply _naturalism_. [226:2] Lucretius: _De Rerum Natura_, Bk. II, lines 569-580. Translation by Munro. [229:3] The reader will find an interesting account of these opposing views in Locke's chapter on _Space_, in his _Essay Concerning Human Understanding_. [230:4] Descartes distinguished his theory from that of Democritus in the _Principles of Philosophy_, Part IV, § ccii. [231:5] Pearson: _Grammar of Science_, pp. 259-260. Cf. _ibid._, Chap. VII, entire. [232:6] Quoted in Ueberweg: _History of Philosophy_, II, p. 124. [233:7] Quoted from the _Opticks_ of Newton by James Ward, in his _Naturalism and Agnosticism_, I, p. 43. [236:8] Haeckel: _Riddle of the Universe_. Translation by McCabe, p. 254. The best systematic presentation of "energetics" is to be found in Ostwald's _Vorlesungen über Natur-Philosophie_. Herbert Spencer, in his well-known _First Principles_, makes philosophical use of both "force" and "energy." [238:9] Cf. Chap. IX. [240:10] Lucretius: _Op. cit._, Bk. I, lines 1021-1237. [241:11] Quoted from La Place's essay on _Probability_ by Ward: _Op. cit._, I, p. 41. [243:12] An interesting account and criticism of such a theory (Clifford's) is to be found in Royce's _Spirit of Modern Philosophy_, Lecture X. [244:13] This method replaced the old theory of "catastrophes" through the efforts of the English geologists, Hutton (1726-1797) and Lyell (1767-1849). [245:14] Harvey's discovery of the circulation of the blood, published in 1628, was regarded as a step in this direction. [250:15] From the account of La Mettrie in Lange: _History of Materialism_. Translation by Thomas, II, pp. 67-68. [251:16] Quoted from Voltaire's London _Letter on the English_, by Lange: _Op. cit._, II, p. 18. [251:17] Quoted by Lange: _Op. cit._, II, p. 113. [252:18] The phrase "psycho-physical parallelism," current in psychology, may mean automatism of the kind expounded above, and may also mean dualism. It is used commonly as a methodological principle to signify that no causal relationship between mind and body, but one of _correspondence_, is to be looked for in empirical psychology. Cf. § 99. [255:19] Quoted by Ward: _Op. cit._, I, p. 18. [256:20] There are times when Huxley, _e. g._, would seem to be on the verge of the Berkeleyan idealism. Cf. Chap. IX. [256:21] For the case of Karl Pearson, read his _Grammar of Science_, Chap. II. [261:22] Pater: _The Renaissance_, pp. 249-250. [262:23] Hobbes: _Leviathan,_ Chap. XV.