1 8 BRAINS OF RATS AND MEN 



If we look at the matter in this way, some very 

 important consequences follow. If our thinking is 

 recognized as an efficient cause of subsequent mental 

 and physiological processes, clearly it influences not 

 only behavior but also the stable personal organiza- 

 tion that we call "disposition" and "character." 

 To some extent, the practice of thinking, deciding, 

 feeling, appreciating, and sympathizing molds the 

 personality of the thinker. Presumably, the stable 

 patterns of cortical association are changed by the 

 performance of these acts just as on a lower plane 

 muscles are changed by systematic exercises. There 

 is thus a certain measure of internal control, through 

 conscious effort, of the course of character-building 

 as truly as there is an internal control in the course of 

 habit formation (perhaps unconsciously) by trial-and- 

 error. To this extent the person controls his own 

 destiny, for human destiny is evaluated not merely 

 by how long we live, but by how we live, what we 

 get out of life for ourselves, and what we contribute 

 to the world in which we live. These are the true 

 measures of the worth of life. 



Obviously, then, thinking, willing, loving, hating, 

 joy and sorrow, are really parts of living on the bio- 

 logical plane, and we biologists and psychologists 

 need not cut ourselves off from the rest of mankind 

 (even academically) by refusing to recognize and 

 employ these useful and on the whole rather pleasant 

 vital processes in our business as professors of science. 

 Indeed, we capitalize our ability to do so, for brain 



