in.] IDEAL GENESIS OF MATTER 251 



derstanding, working on the image supposed to be fixed 

 of the progressing action, shows us parts infinitely mani- 

 fold and an order infinitely well contrived, we catch a 

 glimpse of a simple process, an action which is making 

 itself across an action of the same kind which is unmaking 

 itself, like the fiery path torn by the last rocket of a fire- 

 works display through the black cinders of the spent 

 rockets that are falling dead. 



From this point of view, the general considerations 

 we have presented concerning the evolution of life will 

 be cleared up and completed. We will distinguish more 

 sharply what is accidental from what is essential in this 

 evolution. 



The impetus of life, of which we are speaking, consists 

 in a need of creation. It cannot create absolutely, be- 

 cause it is confronted with matter, that is to say with the 

 movement that is the inverse of its own. But it seizes 

 upon this matter, which is necessity itself, and strives 

 to introduce into it the largest possible amount of indeter- 

 mination and liberty. How does it go to work? 



An animal high in the scale may be represented in 

 a general way, we said, as a sensori-motor nervous system 

 imposed on digestive, respiratory, circulatory systems, 

 etc. The function of these latter is to cleanse, repair 

 and protect the nervous system, to make it as independent 

 as possible of external circumstances, but, above all, to 

 furnish it with energy to be expended in movements. 

 The increasing complexity of the organism is therefore 

 due theoretically (in spite of innumerable exceptions 

 due to accidents of evolution) to the necessity of complexity 

 in the nervous system. No doubt, each complication 

 of any part of the organism involves many others in ad- 

 dition, because this part itself must live, and every change 



