498 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



organs when once called into existence is due to stimuli 

 similar to those which affect the motions of the limbs 

 of the higher animals, is altogether probable. What- 

 ever be its nature, the preliminary to any animal move- 

 ment which is not automatic, is an effort. And as no 

 adaptive movement is automatic the first time it is per- 

 formed, we may regard effort as the immediate source 

 of all movement. Now, effort is a conscious state, and 

 is a sense of resistance to be overcome. When an act 

 is performed without effort, resistance has been over- 

 come, and the mechanism necessary for the performance 

 of the act has been completed. The stage of automa- 

 tism has been reached. At the inception of a new 

 movement resistance is necessarily experienced. It is 

 generally believed that a mental state, as a sensation 

 or a desire, which may or may not stimulate a rational 

 process as an intervening element in the circuit, is 

 concerned in overcoming this resistance. 



A different view is held by certain physiologists and 

 metaphysicians, as e. g. Wundt and Hoffding. Hux- 

 ley thus states his opinion in his Belfast address of 

 I874, 1 a propos of Descartes's doctrine that all animals 

 below man are automata. "The consciousness of 

 brutes would appear to be related to the mechanism of 

 their body simply as a collateral product of its work- 

 ing, and to be as completely without any power of 

 modifying that working as the steam-whistle which 

 accompanies the work of a locomotive-engine is with- 

 out influence on its machinery. Their volition, if they 

 have any, is an emotion indicative of physical changes, not 

 a cause of such changes" (Italics mine.) In other 

 words, stimulus excites conscious states, but the state 

 thus produced has no influence on the resulting act. 



^Scientific Culture and Other Essays, p. 243. 



