in THE MEANING OF EVOLUTION 277 



that of the cerebral activity. In reality, consciousness 

 does not spring from the brain ; but brain and con 

 sciousness correspond because equally they measure, the 

 one by the complexity of its structure and the other by 

 the intensity of its awareness, the quantity of choice that 

 the living being has at its disposal. 



It is precisely because a cerebral state expresses simply 

 what there is of nascent action in the corresponding 

 psychical state, that the psychical state tells us more 

 than the cerebral state. The consciousness of a living 

 being, as we have tried to prove elsewhere, is inseparable 

 from its brain in the sense in which a sharp knife is 

 inseparable from its edge : the brain is the sharp edge 

 by which consciousness cuts into the compact tissue of 

 events, but the brain is no more coextensive with con 

 sciousness than the edge is with the knife. Thus, from 

 the fact that two brains, like that of the ape and that 

 of the man, are very much alike, we cannot conclude 

 that the corresponding consciousnesses are comparable 

 or commensurable. 



But the two brains may perhaps be less alike than 

 we suppose. How can we help being struck by the 

 fact that, while man is capable of learning any sort of 

 exercise, of constructing any sort of object, in short of 

 acquiring any kind of motor habit whatsoever, the faculty 

 of combining new movements is strictly limited in the 

 best-endowed animal, even in the ape? The cerebral 

 characteristic of man is there. The human brain is 

 made, like every brain, to set up motor mechanisms 

 and to enable us to choose among them, at any instant, 

 the one we shall put in motion by the pull of a trigger. 

 But it differs from other brains in this, that the number 

 of mechanisms it can set up, and consequently the choice 

 that it gives as to which among them shall be released, 



