Nature of Evolutionary Progress 39 



pain causes one to withdraw from and avoid that 

 which produces the pain, while a sensation of pleasure 

 or comfort has the reverse effect. 



But somewhat to the astonishment of the natural 

 man, the devotee of mechanism as a philosophy re- 

 jects these conclusions. He holds that sensations, 

 emotions, thoughts, purposes, and opinions have 

 nothing to do with action. He holds, as we have be- 

 fore remarked, that sensations of hunger and thirst 

 have nothing to do with eating and drinking. Sensa- 

 tions of cold do not influence our approach to the fire. 

 Our political sympathies and beliefs have nothing to 

 do with the way we vote. My thoughts and opinions 

 have nothing to do with what I say to you in these 

 lectures. 



How does the mechanist escape from the natural 

 conclusion that sensations, purposes, and opinions 

 influence our actions .^^ He believes that he finds an 

 escape in certain relations between the physical and 

 the mental that we have already mentioned. When 

 different sensations, emotions, thoughts, and pur- 

 poses are present, there are characteristic different 

 physico-chemical conditions as well. When a sensa- 

 tion arises or changes, the physical condition of the 

 organism changes also; when any mental condition 

 alters, there is likewise an alteration in the physical 

 condition. I am physiologically different when I am 

 hungry, as compared with my condition when I am 

 filled. I am physically different when I think, as com- 

 pared with my condition when I do not think. When 

 an idea occurs to me, my body changes within. 



