Children of the same parents are never exactly like either their parents or one another, and they often differ amazingly from both.

In such instances they revert to type, as we say; but inasmuch as the race is steadily advancing in development, such reversion must resemble that of an estate which has been greatly improved since its previous possession.

The appearance of the quality is really the sprouting of a seed whose original germ was in some sense coeval with the beginning of things.
This mind-seed takes root in some cases and not in others, according to the soil it finds.

And as certain traits develop and others do not, one man turns out very differently from his neighbor.

Such inevitable distinction implies furthermore that the man shall be sensible of it.
Consciousness is the necessary attribute of mental action.