WHAT WE DO WITH OUR BRAINS 19 



power (as the man on the street correctly calls it) 

 is the measure of the size of the pay check in the 

 university as well as in the office and factory. 



Some day we may be able to write chemical and 

 energy equations to express the physical changes in 

 my cerebral cortex while I solve a mathematical 

 problem and to map the courses of all of the nervous 

 currents which play back and forth in my brain; but 

 even in advance of that distant day I go on adding 

 the columns of my ledger or whatever else is necessary 

 to. strike a trial balance of my day's work at its close. 



But this is not all. Human thinking employs 

 language and other symbols, by the aid of which we 

 generalize from our experience, discover laws of na- 

 ture, and so prognosticate the future. What I do to- 

 day I do in the light of its probable effect upon tomor- 

 row. Foreknowledge of the probable consequences of 

 my action becomes a causative factor in determining 

 the present act. It is not that I foresee what I shall be 

 compelled to do, but the prevision of the possible 

 results of an action is a causative factor in deciding 

 what I actually do now. The deUberate balancing 

 of consequences of possible action in the hght of 

 general notions, laws of nature, and personal ideals 

 seems to be a distinctive human capacity. We have 

 no satisfactory evidence that any brute can perform 

 this wonderful feat, and we have the best of evidence 

 that in mankind this supernal achievement is a 

 function of the cerebral cortex. 



Here a very particular kind of mind, which is a 



