NATURAL PHILOSOPHY IN ENGLAND 



tion of the solar system was of the crude kind 

 which speculated about the causes of the "first 

 impulse " for the motion of the planets. Still his 

 ideas seemed so dangerous to the theological 

 dualists that for instance Leibniz denounced the 

 Newtonian theory of gravitation, because it un- 

 dermined natural religion and denied revealed 

 religion. The theistic ideas owed a continued ex- 

 istence to the influence of Rousseau and Voltaire, 

 though especially the last-named was a scoffer at 

 all religions based on supernatural revelation. 



But materialism remained close on the trail of 

 metaphysics. In France, Descartes was person- 

 ally confronted by Gassendi, who revived Epi- 

 curean materialism and accomplished for mate- 

 rialism in France what Hobbes did in England. 

 And Pierre Bayle prepared the way for a more 

 mature philosophy in France by a cutting criti- 

 cism of Cartesian metaphysics. Driven by re- 

 ligious doubts to a closer study of metaphysics, 

 Bayle wrote the history of metaphysics only to 

 give dualism a blow from which it would never 

 fully recover. 



After this destructive work of materialistic 

 criticism, Locke appeared as a constructive ma- 

 terialist, in 1690, with his " Essay Concerning 

 Human Understanding," which was enthusias- 



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