318 THE PHILOSOPHY OF BIOLOGY 



chemical transformations beginning with the elements 

 carbon, oxygen, and hydrogen, and ending with the 

 substance sugar, would not have occurred. We have 

 no right to say, therefore, that such syntheses destroy 

 the distinction between the organic and the inorganic. 

 What they do indicate is the distinction between the 

 tendency expressed by the second law of thermo- 

 dynamics (inorganic processes), and those that occur 

 as the result of direction conferred upon processes 

 taken as a whole, either by the vital agency of the living 

 cell, or by the intelligence of man (vital processes). 



The direction, therefore, that may be conferred on 

 a series of physico-chemical processes is what we must 

 understand by the " vital impetus " of Bergson, or the 

 " entelechy " of Driesch. 



It must be admitted that it is difficult to describe 

 more precisely than we have done above what is meant 

 by these terms. It is with very much the same em- 

 barrassment that is experienced by the physicist 

 when he has to apply the concepts of mass and inertia, 

 in their eighteenth-century meaning, to his description 

 of an universe in terms of electro-magnetic theory, that 

 we seek to describe the modern concept of entelechy. 

 Yet the physicist has had to make this step forward, 

 and the same adventure awaits the biologist if the 

 speculative side of his science is to make further pro- 

 gress, and if he is disinclined to make his science an 

 appendage of physics and chemistry. Entelechy does 

 not correspond to the eighteenth-century notion of a 

 " vital force," or to the " soul " of Descartes, as the 

 writer of a book on evolutionary biology seems to 

 suggest. It is a concept which is forced upon us 

 mainly because of the failure of mechanistic hypotheses 

 of the organism. If our physical analysis of the 

 behaviour of the developing embryo, or the evolving 



