4.80 HEREDITY AND ENVIRONMENT 



termination shall we cease to be scientists and 

 close our eyes to the evidence? The first duty 

 of science is to appeal to fact and to settle 

 later with logic and philosophy. Is it not a 

 fact that the possibilities of our inheritance 

 depend for their realization upon development, 

 one of the most important factors of which is 

 use, functional activity in response to stimuli? 

 Is it not a fact that in many animals behavior 

 is modifiable and that impulses may be in- 

 hibited and controlled? Is it not a fact that 

 experience, intelligence, will are factors in 

 human behavior and that by means of these 

 men are often able to choose between alterna- 

 tives and so to control their own activities as 

 well as external phenomena? Is it not a fact 

 that our capacities are very much greater than 

 our habitual demands upon them? Is it not 

 a fact that belief in our responsibility ener- 

 gizes our lives and gives vigor to our mental 

 and moral fiber? Is it not a fact that shifting 

 all responsibility from men to their heredity 

 or to that part of their environment which is 

 beyond their control helps to make them 

 irresponsible? 



