288 BRAINS OF RATS AND MEN 



tern of nature. There is diversity of pattern but no 

 disruption of the unity, no plurahsm in the sense of 

 unrelated systems of events or materials. Even in 

 evolutionary history, where the laws of change them- 

 selves undergo progressive modification from cycle to 

 cycle, the factors of this progression are intrinsic, not 

 extrinsic, to the evolving cosmos. There is no break in 

 the continuity of the process; there is differentiation, 

 but always through the action of resident forces upon 

 pre-existing material. 



Each field of science, accordingly, has its own 

 lawful modes or patterns of structural (static) and 

 functional (dynamic) manifestations, and these in 

 turn are all related members of the total world as 

 known to science. The vital modes (all of them) are 

 thus related with inorganic modes, but without loss of 

 their own differentiae. 



The most complex and distinctive of the vital 

 modes are those related with the nervous system — 

 reflex, instinct, and others. And the biologist must re- 

 gard consciousness (by which I mean some sort of 

 awareness during the progress of bodily functions) as 

 a function of the nervous system in the same sense 

 as are nervous conduction, reflex, and physiological 

 habit. The evidence for this conclusion is of exactly 

 the same sort as that which supports the beUef that 

 contraction is a function of muscular tissue, and to 

 the unprejudiced observer it is equally convincing. 

 My brother (1907, p. 213) has written: 



