PRELUDE TO THE EPOCH OF NEWTON. 147 



Rohault, a zealous disciple of Descartes, was pub- 

 lished at Paris about 1670 18 , and was, for a time, 

 the standard book for students of this subject, both 

 in France and in England. I do not here speak 

 of the later defenders of the Cartesian system, for, 

 in their hands, it was much modified by the strug- 

 gle which it had to maintain against the Newtonian 

 system. 



We are concerned with Descartes and his school 

 only as they form part of the picture of the intel- 

 lectual condition of Europe just before the publi- 

 cation of Newton's discoveries. Beyond this, the 

 Cartesian speculations are without value. When, in- 

 deed, Descartes' countrymen could no longer refuse 

 their assent and admiration to the Newtonian theory, 

 it came to be the fashion among them to say that 

 Descartes had been the necessary precursor of New- 

 ton ; and to adopt a favourite saying of Leibnitz, 

 that the Cartesian philosophy was the antechamber 

 of Truth. Yet this comparison is far from being 

 happy: it appeared rather as if these suitors had 

 mistaken the door; for those who first came into the 

 presence of Truth herself, were those who never 

 entered this imagined antechamber, and those who 

 were in the antechamber first, were the last in pene- 

 trating further. In partly the same spirit, Playfair 

 has noted it as a service which Newton perhaps 

 owed to Descartes, that "he had exhausted one of 

 the most tempting forms of error." We shall see 

 19 And a second edition in 1672. 



L2 



