ment, utilizing every canon of induction, the facts of development 

 are to be brought under wide general laws of causation, which 

 will be in the first instance physiological laws of 'response to 

 stimuli, of metabolism, and of growth : by means of these laws 

 we can predict, and our predictions can be verified. The 

 thought process cannot, however, rest here. Ultimately as we 

 believe it may be possible, no more than that can yet be said, 

 but it may be possible to state the widest generalizations of 

 biology in chemical and physical, and these again in purely 

 mechanical, terms. Thus evolution of form in the individual as 

 well as the larger evolution of form in the race, become but the 

 final terms in a far vaster cosmic progress, from ' homogeneity 

 to heterogeneity'. 



The idea, of course, is perfectly familiar ; it is the analysis of 

 purely physical causes carried to its extremest limit. Phenomena 

 are thought out in terms not of origins merely but of one origin, 

 and that one origin is the only mystery that remains. This 

 unification of the sciences always has been, and must still remain, 

 the dream and the faith and the inspiration of the scientific man, 

 and could such an edifice of the intellect ever be realized the 

 task of science would have been completed. 



But where science leaves off there philosophy begins, and it 

 is for philosophy to attempt the solution of this last mystery 

 of all. 



Philosophy cannot rest content in an endless regress of cause 

 and effect, and a first supreme cause, first in time that is, is 

 metaphysically out of the question. An original homogeneity 

 is equally unthinkable, for out of a system all whose parts are 

 absolutely alike, by no imaginable process could any hetero- 

 geneity ever be evolved. 



That first simplicity must have contained potentid all that has 

 since developed out of it, it must have possessed a structure, an 

 arrangement of parts such that the end which it has realized, or is 

 to realize, would be what it is or will be, and to regard the end as 

 well as the beginning is the duty of philosophy, a duty which 

 Aristotle and Kant have both impressed on us. The outlook of 

 pure science, an outlook to which, qua science, it cannot too 

 rigidly confine itself, is thus supplemented and enlarged. 



