His creatures depend entirely upon Him." ((Euvres, 

 VI. 109.) The test of truth is "the evident concep- 

 tion of a healthy and attentive mind, so clear and 

 distinct that no doubt is left." ((Euvres, XI. 212.) 

 Apparently, then, if on any question there be 

 different opinions, that one is infallibly true which 

 is the conception of a " healthy " mind ; it will, 

 moreover, be in accordance with " the truths styled 

 eternal" which " have been established by God." 



Descartes does, however, find an opening for a 

 science which should depend to some extent upon 

 observation, and he finds it nearly in the same way as 

 Copernicus had done. In his "Principiae Philo- 

 sophic," III. 45, after premising that "undoubtedly 

 the world was in the beginning created in all its 

 perfection," he writes, " But yet, as it is best if we 

 wish to understand the nature of plants, or of men, to 

 consider how they may by degrees proceed from 

 seeds, rather than how they were created by God in 

 the beginning of the world ; so, if we can excogitate 

 some extremely simple and comprehensible prin- 

 ciple out of which, as if they were seeds, we can 

 prove that the stars and earth and all this visible 

 scene could have originated, although we know full 

 well that they never did originate in such a way, we 

 shall in that way expound their nature far better 

 than if we merely described them as they exist at 

 present." 



Many systems have, like that of Descartes, taken 



