Mechanistic Biology 247 



whether the mechanistic theory of life is as strong on the philo- 

 sophical side as it is on the experimental. 



As has been shown in one of the earlier essays in this book, 

 naturalism gained ground by immense strides during the first 

 seventy-five years of the nineteenth century, but came to a climax 

 about then, and has been undergoing severe criticism ever since. 



In the first place the general acceptance of the evolution theory 

 had vastly different effects from anything that Huxley and Spencer 

 could have conceived. It affected the philosophers profoundly, 

 for apart from raising difficulties over the question of how muta- 

 tions and the production of new species could possibly follow 

 from mechanical laws, how qualitative transformation could result 

 from quantitative permanence and determinism, it led also to a 

 subjective position represented later by many minds. Naturally 

 enough, if man had been evolved in the struggle for existence, as the 

 evolutionists said, then his mind also must be conceived of as the 

 product of such a struggle and could therefore hardly be fitted for 

 the grasping of absolute truth. " The forceps of our mind are 

 crude," said Bergson later, " and they crush the delicacy of reality 

 when we attempt to hold it." This argument from evolution was 

 also applied in the physiological world by Poincare to the genesis 

 of our sense of space. 



More important for our purposes are the criticisms of the 

 scientific method which were made by Mach, LeRoy, and Duhem. 

 Mach pointed out that science has a biological end; it is a kind of 

 shorthand, it guides man through an impossible maze of facts, 

 and without it he would be lost. But in doing so it necessarily 

 abstracts from those facts and gives him a sketch, not a complete 

 picture. Mach distinguished three periods in scientific thought, 

 the first experimental, in direct contact with reality, the second 

 deductive, not so much in contact, and the third theoretical or 

 formal, entirely subjective. Scientific descriptions, mechanistic 

 descriptions, according to Mach, are " quite fictitious, though still 

 valuable modes of describing phenomena, and to place the laws of 

 physics actually in external nature is to hypostatise an abstraction 

 of purely human origin." In his constructive suggestions he was not 

 perhaps so happy, for, as Aliotta says, he replaced " a mechanical 

 by a sensorial mythology." Boutroux, anticipating Bergson, 

 maintained that the scientific method takes us farther away from 

 rather than nearer to the nature of reality, because it is forced to 



