356 DARWINISM AND THE PROBLEMS OF LIFE 



the mechanical conception that we are bound to prefer 

 the latter. Selection is precisely proved in a most 

 striking way by the imperfectness of the adaptations. 



Finally, the objection has been raised against the 

 mechanical theory that all evolution pre-supposes some- 

 thing that cannot be explained physico - chemically. 

 This is the will to live. The struggle for life is not 

 imposed from without on organisms ; it is rooted in 

 their own will. Selection would accomplish nothing — 

 it would effect no improvement if living things did not 

 strive to maintain themselves and reproduce. 



We cannot accept this view. The will to live is 

 synonymous with the impulse of self-preservation. 

 This is an instinct, and we said that there is no difficulty 

 in attributing the origin of instincts to natural selection. 

 Moreover, the will to live and to reproduce is not 

 primary. It is certainly not present in the lowest 

 protozoa. These have no will to nourish themselves. 

 They travel about and take into their bodies everything 

 that comes in their way. If the particles are digestible 

 they are used for building up the animal ; if not, there 

 was no use in absorbing them. When the lowest 

 mobile algae swim towards the light, they do not do 

 this in virtue of a will to live, but because an attractive 

 force has been developed in their frame by selection that 

 impels them towards the light, which is important to them. 



Still less can we speak of a will to reproduce. The 

 cleavage of an amoeba clearly means merely that when 

 it has absorbed a certain quantity of food it breaks up of 

 itself, just as steam on the window runs down at length 

 in drops. 



