ii.l ADAPTATION AND PROGRESS 103 



But, if the evolution of life is something other than 

 a series of adaptations to accidental circumstances, so 

 also it is not the realization of a plan. A plan is given 

 in advance. It is represented, or at least representable, 

 before its realization. The complete execution of it 

 may be put off to a distant future, or even indefinitely; 

 but the idea is none the less formulable at the present 

 time, in terms actually given. If, on the contrary, evo- 

 lution is a creation unceasingly renewed, it creates, as 

 it goes on, not only the forms of life, but the ideas that 

 will enable the intellect to understand it, the terms which 

 will serve to express it. That is to say that its future 

 overflows its present, and can not be sketched out therein 

 in an idea. 



There is the first error of finalism. It involves another, 

 yet more serious. 



If life realizes a plan, it ought to manifest a greater 

 harmony the further it advances, just as the house shows 

 better and better the idea of the architect as stone is set 

 upon stone. If, on the contrary, the unity of life is to be 

 found solely in the impetus that pushes it along the road 

 of time, the harmony is not in front, but behind. The unity 

 is derived from & vis a tergo: it is given at the start as an 

 impulsion, not placed at the end as an attraction. In 

 communicating itself, the impetus splits up more and more. 

 Life, in proportion to its progress, is scattered in mani- 

 festations which undoubtedly owe to their common origin 

 the fact that they are complementary to each other in 

 certain aspects, but which are none the less mutually 

 incompatible and antagonistic. So the discord between 

 species will go on increasing. Indeed, we have as yet 

 only indicated the essential cause of it. We have sup- 

 posed, for the sake of simplicity, that each species received 

 the impulsion in order to pass it on to others, and that, 



