Manc/iestcr JMcjiioirs, Vol. Iv. (1910), No. 4. 5 



little SyntagJiia of Epicurus' philosophy, and that most 

 ingenious gentleman, Mons. Descartes, his principles of 

 philosophy." " He did not see any necessity to ally 

 himself with one party or the other. " Notwithstanding 

 those things, wherein the atomists and the Cartesians 

 differed, they might be thought to agree in the main, and 

 their hypotheses might, by a person of a reconciling 

 disposition, be looked on . . . as one philosophy." ^^ 



Science has often gained immensely by a wise limita- 

 tion of the problem to be solved. Descartes' theory, that 

 space is pervaded by an ethereal fluid, and that ordinary 

 matter consists of atoms swimming in the ether, is 

 formally complete, and has to be adopted sooner or later. 

 Yet Gassend's theory, which is incomplete, since it ignores 

 the ether, and concentrates attention on the atoms, proved 

 more helpful to science in the first instance. Newton 

 was more inclined to Gassend's way of thinking than to 

 Descartes'. In the " Principia" he would not consider the 

 mechanism of gravitation, and in the course of his atomic 

 speculations he almost leaves out of account the means 

 by which chemical attraction arises. Nevertheless, 

 Newton was influenced by Descartes. 



The Cartesian natural philosophy was predominant 

 throughout Europe for the most part of the seventeenth 

 century, and, in the eighteenth, it was supplanted by 

 the Newtonian philosophy, as expounded in the 

 " Principia." The two philosophies being opposed 

 to one another, no one apparently has reflected how 

 much Newton may have been indebted to Descartes. 

 The mere fact that Cartesianism was dominant during the 

 seventeenth century means that Newton must have made 

 himself master of that system of nature. Presumably 



'1 op. fit., vol. I, p. 194. 



12 op. cit., vol. I, p. 227-228. 



