BIOLOGY IN HUMAN AFFAIRS 



man has a soul. For that entity he had to find a local 

 habitation and a name. He was advanced enough to look 

 for it in the brain, which, unfortunately for his notion of 

 unity, was divided into two hemispheres and symmetrical 

 throughout; so he selected the pineal gland, which is 

 single and near the center of the brain, for the place of 

 honor as the seat of the soul. Descartes, as psychologist, 

 likewise considered the "passions" or emotions, conceiving 

 them in similar mechanistic fashion, analyzing them as 

 intellectual calculations in terms of pleasure forces, or as 

 actions and reactions of attraction and repulsion. What 

 the gland actually was, he could not know. What is 

 pertinent is that he did not think it necessary to inquire. 

 He actually "proved" his own existence by the fact that 

 he could think about it : cogito, ergo sum. He thought he could 

 get at the bottom truth about things, and particularly how 

 we can have knowledge of them, by emptying his mind of 

 all presuppositions, then examining them critically, and 

 demonstrating their validity. It has been neatly said that 

 he took all his mental furniture out of its house, examined 

 it, and put it back again. To us this seems learnedly 

 futile; yet it represents the level and procedure of the 

 "psychology" of three centuries ago. 



Leibnitz (1646-1716), the leading philosopher of the 

 following generation, regarded the relations of mind and 

 body as regulated by a "pre-established harmony," with 

 neither as cause or effect of the other; the two clocks, 

 body and mind, were set once for all to keep the same time. 

 In grading mental processes he came upon the fact that 

 some were obscure and unconscious, coming from within 

 the body, others clear perceptions directed outward — a 

 discerning observation but not followed to its rich 

 possibilities. 



Hobbes (158&-1679) was mainly a pleasure-and-pain, 

 profit-and-loss psychologist entering the field from the 



[58] 



