Enneads III.1: Concerning Fate
Heredity More Important Than Star-influence; Continuation
6. Each being derives his character from his nature. One being is a horse because he is born from a mare, while another is human, because born from a human mother; and more: he is that particular horse, and that particular man because he is born from such and such a horse, or woman. Doubtless, the course of the stars may modify the result, but the greatest part of the influence must be allowed to heredity.