224 Science Religion and Reality 



direction. Physiology, which had had httle to say to the evohi- 

 tion theory, since taxonomic classification had been founded on 

 differences of form rather than of function, now began to occupy 

 more and more the centre of the field, and as this process went on 

 it was seen that physiology wore no longer the garments in which 

 traditional teaching had pictured herj but appeared in the breast- 

 plate of chemistry, the helmet of physics, and armed with the spear 

 of mathematics. As time went on the hitherto neglected subject 

 of biochemistry became more and more important, so that at the 

 present day zoology has become comparative biochemistry and 

 physiology biophysics. The causes for the change lie deep, but 

 the effect has been a profound infiltration of physico-chemical ideas 

 and terminology into the whole biological field, and this implies 

 a corresponding peaceful penetration of the mechanistic theory of 

 life. This change from comparative morphology to comparative 

 biochemistry is indeed one of the most important factors in the 

 scientific history of the last few decades. It will never again be 

 equalled in importance until comparative biochemistry passes over 

 into electronic biophysics. For it means that we have passed one 

 step deeper into the problem of life — important as the distribution 

 and form of organisms may be, it cannot be so much so as the actual 

 examination of the physico-chemical attributes of living matter 

 itself, of the universal substrate of the innumerable manifestations 

 of living beings. The forms of the different types of sea-urchins 

 are truly most interesting, but they are only the forms taken by 

 the same chemical elements, and in this case as in others the body 

 is more than the raiment. 



This profound change in the domain of science has had its 

 effects on philosophy. Whereas evolution was the key-interest 

 of biological philosophy fifty years ago, it is now so no longer, for 

 a more comprehensive problem has supplanted it. The mechan- 

 istic theory of life is now the important problem, and the rela- 

 tions of biological science to religion are accordingly altered. 

 Mechanism is a more inclusive conception than evolution, it is 

 deeper, and therefore it more definitely demands the co-operation 

 of philosophy. 



But the mechanistic theory of life is not new. On the con- 

 trary, it is one of man's earliest speculations. And throughout 

 its history it has had to suffer the opposition of religious thought 

 because it has, as a rule, been linked in thought with materialism or 



