LAMARCK'S VITALISM 225 



state in which we now see them, become easily determin- 

 able" (p. 1 68). 



It is never made quite clear, we may note in passing, how 

 far his second and third laws tend to bring about an increase 

 in complexity, in addition to diversifying animals. 1 



" The function creates the organ," this would seem to be 

 the kernel of Lamarck's doctrine. But how does he reconcile 

 this essentially vitalistic conception with his strictly material- 

 istic philosophy ? 



We have seen that irritability, the sentiment interieur, 

 and intelligence itself, are the effects of organisation. We 

 are told farther on that both the sentiment and intelligence 

 are caused by nervous fluids. A great part of both the 

 PJiilosopliie zoologiqne and the introduction to the Animaux 

 sans Vertcbres is given up to the exposition of a materialistic 

 psychology of animals and man, based entirely upon this 

 hypothesis of nervous fluids. Thus habits are due to the 

 fluids hollowing out definite paths for themselves. 



The sentiment interieur acts by directing the movements of 

 the subtle fluids of the body (which are themselves modifica- 

 tions of the nervous fluids) upon the parts where a new organ 

 is needed. But if it is itself only a result of the movement 

 of nervous fluids? Again, how can a need be "felt" by a 

 nervous fluid? This is an entirely psychological notion and 

 cannot be applied to a purely material system. Whence 

 arises the power of the sentiment interieur to canalise the 

 energies of the organism, so to direct and co-ordinate them 

 that they build up purposive structures, or effect purposive 

 actions (as in all instinctive behaviour)? Either the senti- 

 ment interieur is a psychological faculty, or it is nothing. 



There is no doubt that, as expressed by Lamarck, the 

 conception conceals a radical confusion of thought. It is 

 not possible to be a thorough-going materialist, and at the 



1 Contrast Treviranus " In every living being there exists a capa- 

 bility of an endless variety of form-assumption ; each possesses the 

 power to adapt its organisation to the changes of the outer world, and 

 it is this power, put into action by the change of the universe, that has 

 raised the simple zoophytes of the primitive world to continually higher 

 stages of organisation, and has introduced a countless variety of species 

 into animate Nature." Quoted by Haeckel in History of Creation, i., 

 p. 93, 1876. 



