WHAT WE DO WITH OUR BRAINS 17 



in turn cause other bodily acts. The evidence that 

 mind is a function of brain (mind in the ordinary 

 sense in which we use the term in science and in 

 common life) is of exactly the same sort as the evi- 

 dence that in birds flight is a function of wings, and 

 to an unprejudiced observer it is quite as convincing. 

 This means, of course, that thinking is mechanisti- 

 cally determined, the same as flying and walking; 

 and also that thinking is a true cause of subsequent 

 events — not an epiphenomenon.^ We do not know 

 how the brain thinks, nor as much as we would like 

 about how a muscle contracts; but this does not forbid 

 accepting the evidence that these organs do perform 

 these functions. 



^ The expression "mechanistic determinism" inevitably carries with 

 it some metaphysical implications which we do not wish to discuss here. 

 RBut to avoid misunderstanding it is necessary to point out at the start 

 » that our conception of determinism does not imply that the entire history 

 of our cosmos was wrapped up in definitive form at its primordial origin. 

 Cosmic evolution, like organic growth, is not a mere unfolding of what 

 was already there; it is a creative process. New patterns are fabricated 

 out of old materials by natural agencies. What is now has been deter- 

 mined in causal sequence. It is also a determining cause of what will be 

 next. 



In ordinary scientific usage the concepts of cause, mechanism and 

 determinism are empirically formulated. A causal sequence implies an 

 observed and verifiable uniformity of orderly progress of events. Each 

 component of the causal sequence is a determining agent in the sense 

 that the succeeding events would be difFerenf if it were absent. In this 

 empirical sense it is necessary. A new causal factor enters at every change. 

 Mechanistic determinism thus resolves itself into a progressive deter- 

 mining. Some implications of this naive naturalistic way of looking at 

 experience are elaborated in another work now in process of prepara- 

 tion. 



