3io Heredity and Environment 



in science and in actual life is that every effect is the resultant of 

 antecedent causes and that identical causes yield identical results. 

 Determinism does not mean predeterminism : the one finds every 

 effect to be due to a long chain of preceding causes, the other at- 

 tributes every effect to a single original cause; the one is scien- 

 tific naturalism, the other is fatalism. 



Applying this to personality actual experience teaches that 

 constant conditions of heredity and environment give constant 

 results in development and that different conditions give differ- 

 ent results. Undoubtedly the entire personality, body and mind, 

 undergoes development, and modifications of either heredity or 

 environment modify personality. This is scientific determinism, 

 but it is not fatalism and it is not incompatible with a certain 

 amount of freedom and responsibility. 



2. Control of Phenomena and of Self. Even the most extreme 

 mechanists, who maintain that we are mere automata and that 

 we could never do otherwise than we do, admit the possibility of 

 a certain amount of control over phenomena outside ourselves. 

 They tell us that the aim of science is not merely to understand 

 but also to control nature. But if man may to a limited extent 

 control physical, chemical and biological processes in the world 

 around him, if he may control to a limited extent the behavior of 

 a star-fish or dog or child, on what ground is it possible to deny 

 a similar control of his own behavior? Does it not come to this 

 that all such control means intelligent action, or rather the intro- 

 duction of intelligence as a factor in the chain of cause and effect? 

 Before the appearance of intelligence, whether in ontogeny or 

 in phylogeny, no such control of phenomena or of self is possible, 

 but when intelligence becomes a factor in behavior a limited 

 control of the world and of the self is made possible. 



Of course man has no control over events which have already 

 happened. Our heredity and early development are accomplished 

 facts which nothing can change. Development is not a reversible 

 process ; a man cannot enter a second time into his mother's womb 

 and be born again. Once the sex cells are formed their heredi- 



