Mechanistic Biology 237 



been called outside the scientific world, by Bernard Shaw and others, 

 the Life-Force. 



Driesch considered the organism as a type of manifoldness which 

 is at the same time a unity, and in which, besides the obvious 

 extensive manifoldness, there was a sort of intensive manifoldness 

 appearing from inside outwards. The cause at work Driesch 

 called the entelechy, borrowing an Aristotelian word for the 

 occasion. Most explicitly he defines this factor as possessing 

 psychoid properties of willing and knowing and as not being con- 

 scious, though he is equally sure that it is not material, not a physical 

 thing. It stands intermediate between everything, and it is much 

 easier to say what it is not than what it is. Its mode of operation 

 he conceives of as being the intimate regulation of the physico- 

 chemical processes on the body ; it does nothing active itself but it 

 suspends other processes at one time and releases them at another. 

 For example, transformations of energy-distribution necessitated 

 by differences of chemical potential would be held up by the 

 entelechy until the proper time had come to allow them to go 

 forward. 



But Driesch also adds a logical speculative argument. He 

 starts by maintaining that there cannot be more content in the 

 effect than there was in the cause. Therefore, since the pre- 

 dominant attribute of developing organisms is their continual 

 increase in complexity and differentiation, the original cause, the 

 undivided ovum, is insufficient alone to account for the change, and 

 something outside must be postulated. 



Haldane, on the other hand, was led to neo-vitalism entirely 

 by experiments on the adult animal. To Haldane, as to Driesch, 

 the functions of separate organs may admit of physico-chemical 

 description, but the body as a whole in all its efficiency of co- 

 ordination and purposiveness cannot do so. No constellation of 

 purely physical and chemical facts can account for the fertility 

 and co-ordinateness of adaptation. The kernel of the nut which 

 physics and chemistry will never be able to crack, lies for him in the 

 continual tendency of the organism to keep its environment, both 

 exterior and interior, constant. The animal body continually 

 tends to maintain the conditions optimum for its own existence, and 

 Haldane cannot conceive of a machine being able to do that 

 Haldane also considers quite impossible the mechanistic theory 

 of heredity. " On the mechanistic theory," he says, " the cell- 



