DEVELOPMENT BY NATURAL SELECTION. 127 



was essentially mechanistic. To realise this one has 

 only to glance at books of the type of Paley's Evidences 

 of Christianity, with its comparison of the living bo<l\ 

 to the machinery of a watch. Had Darwin made an 

 actual physiological study of variation in the individual 

 in response to changes or accidents of environment, 1 

 think that with his singularly acute outlook he would 

 soon have seen that the mechanistic theory of life cannot 

 be reconciled with the fact of evolution. If the mechan- 

 istic theory were correct, Darwin's own expression, 

 1 the struggle for existence," would cease to have any 

 meaning : for matter on the mechanistic hypothesis 

 cannot help existing, and cannot " exist " any better 

 in one form than in another. But the verv life of an 

 organism is, as I have tried to show, a constant struggle 

 for definite order — a constant adapting. In the evolu- 

 tion of living organisms we thus see a progressive evolu- 

 tion of order out of chaos. The imperfection of the 

 order, as Darwin showed, is bound up with the develop- 

 ment. But for either struggle or development to occur 

 living organisms must have the distinctive characters 

 of living organisms ; and development is the outcome 

 of life, not of mechanism. The further back, therefore, 

 we can trace the course of development, the further 

 we are pushing biological interpretations towards that 

 region of our relative ignorance which we call the in- 

 organic world ; and this is the special point which I 

 set out to make. 



Perhaps I may be asked whether it matters to us what 

 particular view we take of life, evolution, and the in- 

 organic world. To me it seems to matter a great deal. 

 Some members of my audience have probably read a 



