Marcus Tullius Cicero

Our character is not so much the product of race and heredity as of those circumstances by which nature forms our habits, by which we are nurtured and live.

Nature abhors annihilation.

Virtue is a habit of the mind, consistent with nature and moderation and reason.

There are more men ennobled by study than by nature.

Time destroys the speculation of men, but it confirms nature.

Nature has planted in our minds an insatiable longing to see the truth.