SCIENCE AND PHILOSOPHY 145 



And this also must be remembered in comparing 

 a living creature with a machine, that the latter 

 is no ordinary sample of the inorganic world. It 

 is an elaborated tool, an extended hand, and has 

 inside of it a human thought. It is because of 

 these qualities that highly complex machines come 

 to be so like organisms. But no machine profits 

 by experience, nor trades with time as organisms 

 do." Only living creatures have a persistent 

 unified behaviour, a power of profiting by experi- 

 ence, and a creative capacity as genuine agents. 

 Here, then, we have one of the great contrasts 

 in Nature, between the purely physical order and 

 the world of organisms. The scientific question 

 is whether the concepts and formulae that suffice 

 for the description of the inorganic world are also 

 sufficient for the description of vital functions 

 and animate behaviour. The answer of the 

 mechanistic school is "Yes"; all others say 

 "No," but not always for the same reasons. 

 We say "No" for the following reasons: 

 (1) There are many chemical and physical 

 operations in a living body, but as a matter of 

 fact no complete physico-chemical description 

 has yet been given of any distinctively vital 

 activity. It has to be remembered that the most 

 salient fact is the correlation and control of all 

 the manifold chemical and physical processes so 

 that a unified behaviour results. 



