FIRST PRINCIPLES 29 



takes a plunge, as it were, into the uncertain sea, trusting 

 to reach firm ground again before its power of swimming 

 is exhausted ; whereas science, more cautious, builds solid 

 facts into a causeway, and never allows the waves of uncer- 

 tainty to wet it above the ankles. But yet it is a question 

 only of degree, for the shortest hypothesis which bridges 

 across from fact to fact is in itself as wanting in solidity as the 

 widest generalisation of which the human mind is capable ; 

 and the widest generalisation is equally with the narrowest 

 but an attempt to unite isolated territories of solid fact. 

 The process of reasoning is in the two cases the same ; 

 but the one regards certainty as the chief desideratum, the 

 other aims at enunciating the theory which will embrace 

 the greatest number of phenomena within its scope. ' ' Scien- 

 tific " and " philosophical " are not antithetical terms, for 

 there can be no opposition between science and philosophy. 

 It would be easy to show, seeing that the scientific process 

 the process of induction is carried to the utmost confines 

 of thought, that all products of human intelligence deserve 

 to be classed as science ; or, on the other hand, since 

 knowledge acquires value only when worked into thought, 

 the whole field of science might with equal propriety be 

 assigned to philosophy. 



The Senses the Agents of the Mind. From very 

 ancient times it has been recognized that the great brain or 

 cerebrum is the seat of consciousness, thought and volition. 

 It may now be asserted that the cortex, or sheet of grey 

 matter which covers the cerebral hemispheres, is alone con- 

 cerned with these processes. The cortex cerebri is therefore 

 the apparatus of mind. Prior to 1870 the brain was a 

 mysterious organ, forbidding further physiological explora- 

 tion. It was thought that it functioned " as a whole, ' ' and 

 any attempt to analyse the constituent physiological pro- 

 cesses of the act of thinking was looked upon as frivolous if 

 not sacrilegious. Our mode of viewing the apparatus of 

 thought has undergone a great change since 1870. Since 



