70 Heredity 



combination and differentiation ; but it still remains true that these 

 two facts themselves exist only in and by thought, and we do not 

 know what thought is. If we add that these phenomena are given 

 us under the form of a sequence, or of simple series, and that suc- 

 cession is the essential condition of consciousness, we do but 

 express the form of thought, not its nature, for things may be 

 successive without being facts of consciousness. Thought, there- 

 fore, is still impenetrable to us : it explains all things, but does not 

 explain itself; it is one of those noumena wherewith we solve the 

 enigma of the universe, but it is itself an enigma. 



The unity of the intellect is an indisputable fact, established alike 

 by consciousness, experience, and theory. Nothing, therefore, could 

 be more chimerical that to suppose that given intellectual opera- 

 tions are, by their own nature, beyond the laws of heredity. Logic 

 rejects any such conclusion, and it is no less contradicted by facts. 



It will, perhaps, excite surprise that, in the foregoing remarks, we 

 have not named that highest mode of intellect which metaphysi- 

 cians call reason. This faculty whose object, according to some, 

 is the absolute, the infinite, the perfect, according to others, the 

 necessary process of thought is pre-eminently the metaphysical 

 faculty. It has its seat in that region of the impalpable and the 

 invisible where we look for the ultimate reasons of things. It lies 

 so far above experience that, in a study on experimental psychology, 

 we are almost obliged not to speak of it. We need only declare 

 our position with regard to every possible theory of reason. 



Metaphysicians are by no means agreed as to the nature of 

 this faculty. In France, a theory, borrowed from Leibnitz, 

 broadened and deepened by idealists in our own day, reduces 

 reason to two constituent principles, viz. the principle of contra- 

 diction or of identity, and the principle of raison suffisante both 

 ultimately reducible to one. The principle of identity, the last 

 resort of logic and science, is subordinate to the principle of 

 raison, suffisante, which is the ultimate principle of all existences, 

 because the latter accounts for all things, is not limited to the 

 declaration that a thing is, but why it is, and what determined its 

 existence ; and this ultimate principle itself would not be explic- 

 able were it not that it implies the summum intdligibile, which is 

 identical with the good. All things, therefore, would be reduced 



