328 



PHILOSOPHICAL THOUGHT. 



around this illuminated portion there lies the region of 

 the " petites perceptions," the half illuminated storehouse 

 of thought. These " petites perceptions " accompany as 

 a background all our thinking, as they also form the 

 source and guarantee the continuity of all our thoughts. 

 This suggestive view put forward by Leibniz has also 

 been taken up in various forms by thinkers during the 

 nineteenth century. But Leibniz's immediate successors 

 took more interest in the process by which what was 

 unclear and mystical might be drawn into clear daylight 

 than in emphasising those internal possessions of the 

 human mind which can never be completely ration- 

 alised. 1 



believe in the possibility that the 

 highest faculties of the mind could 

 some day be reduced to a mechan- 

 ism ; in fact, he did not shrink 

 even from the consequence that if 

 once such a method were found it 

 would require only experience and 

 ingenuity to find new truths : a 

 genius himself, he strove to make 

 genius superfluous " (Windelband, 

 ' Geschichte der Neueren Philo- 

 sophic,' vol. i., 4th ed., 1907, p. 

 468). The term " petites per- 

 ceptions " was characteristic of 

 Leibniz's manner of looking at 

 things, and had no doubt its origin 

 in the infinitesimal method which 

 he perfected and applied in the 

 calculus : it combined the spirit of 

 analysis with the principle of Con- 

 tinuity which forms another funda- 

 mental notion in Leibniz's specu- 

 lation. What in recent psychology 

 is termed the " presentation -con- 

 tinuum " or the " plenum of con- 

 sciousness " was mathematically 

 represented in Leibniz's mind by 

 the totality or continuous back- 

 ground of the " petites perceptions," 

 in the same way as geometrical 

 structures may be treated as the 



integrals of their infinitesimal ele- 

 ments or differentials. The ques- 

 tion then arose, how, on this 

 continuous background or out of 

 this half illuminated store of per- 

 ceptions, certain among them rose 

 into distinct vision. This led to 

 the doctrine of apperception, which 

 involved at the same time an activity 

 of the human intellect ; likewise 

 an idea which we meet with again 

 more fully developed in recent psy- 

 chology. (See supra, p. 290.) 



1 The study of Leibniz's philo- 

 sophy and its continued influence 

 on philosophical thought ever since 

 affords a good example of the 

 difference between a history of 

 philosophy or of philosophical sys- 

 tems and a history of philosophical 

 thought. Leibniz, more like Des- 

 cartes, and in contrast to Spinoza, 

 published no concise and connected 

 statement of his reasoned creed. 

 Nearly all his writings seem to 

 have been suggested by those of 

 otjier thinkers, or for special per- 

 sons, and on special occasions. 

 Thus the ' Monadology ' was written 

 in 1714, for Prince Eugene of 

 Savoy, in order to promote a better 



