36 THE UNFATHOMED UNIVERSE 



when each recognises its abstractness ; and the hope of their 

 leading on to a philosophical order is in proportion to the 

 clearness with which it is recognised that a synthesis is not 

 additive. 



It is customary to speak of the unity of the sciences, and 

 no doubt they are beginning to form a system or hierarchy, 

 but the ideal of one science of Nature the ideal of Descartes, 

 of Hobbes, of Leibniz is giving place to an ideal of cor- 

 relation rather than of unity. There has been much profit- 

 able breaking down of artificial partitions, much fruitful 

 co-operation of several sciences on one problem, many a use- 

 ful discovery of a common denominator bringing apparently 

 disconnected facts into comparable relationship, but the 

 materialistic proposal to make physiology a branch of 

 physics, and psychology a branch of physiology, has not been 

 substantiated. Biology and Psychology remain autonomous, 

 with categories of their own. Treating of the work of science, 

 Prof. A. E. Dolbear writes : " By explanation is meant the 

 presentation of the mechanical antecedents for a phenomenon 

 in so complete a way that no supplementary or unknown 

 factors are necessary." If that kind of explanation were 

 feasible throughout, there would be one science of Nature, 

 in terms of ideal motions, expressible in mathematical 

 formula. But this is false simplicity; it does not really 

 work. Thus, to take a clear case, in the higher reaches of 

 animal behaviour, most biologists admit the necessity of 

 invoking other than mechanical factors. 



The second hopeful sign we have already referred to, the 

 frank recognition on the part of science that it is not its 

 role to solve the riddles of the universe. It remains more 

 or less open to students of science to deny the feasibility 

 of any solution and to doubt the value of any generalisations 



