He has certain powers given him by his forbears, which may have been developed or repressed by his surroundings. With those powers, as modified by the influences surrounding and outside himself, he may do all that his nature desires and is able to do. Up to the limit of his inherited powers he may do all that his environment (his experiences) have taught or incited him to do.
To speak of a man conquering his environment is the same thing as to speak of a man swimming against a stream. He can swim against the stream if he has strength and skill to overcome the stream. His strength is his heredity: his skill is the result of his environment. If his strength and skill are more than equal to the force of the stream he will conquer his environment; if the stream is too strong for him he will be conquered by his environment.
His acts, in short, depend wholly upon his nature and his environment: neither of which is of his own choosing. Of this I will say more in its place.
A man gets his nature from his forbears, just as certainly as he gets the shape of his nose, the length of his foot, and the colour of his eyes from his forbears.
As we do not blame a man for being born with red or black hair, why should we blame him for being born with strong passions or base desires?
If it is foolish to blame a child for being born with a deformed or weak spine, how can it be reasonable to blame him for being born with a deformed or weak brain?
The nature and quality of his hair and his eyes, of his spine and his brain, of his passions and desires, were all settled for and not by him before he drew the breath of life.
If we blame a man because he has inherited fickleness from an Italian grandfather, or praise him because he has inherited steadfastness from a Dutch grandmother, we are actually praising or blaming him because, before he was born, an Italian married a Hollander.
If we blame a man for inheriting cupidity from an ancestor who was greedy and rapacious, or for inheriting licentious inclinations from an ancestor who was a rake, we are blaming him for failing to be born of better parents.
Briefly, then, heredity makes, and environment modifies, a man's nature. And both these forces are outside the man.