[Prudence] is the virtue of that part of the intellect [the calculative] to which it belongs; and . . . our choice of actions will not be right without Prudence any more than without Moral Virtue, since, while Moral Virtue enables us to achieve the end, Prudence makes us adopt the right means to the end.

What is the essence of life? To serve others and to do good.

To be conscious that we are perceiving or thinking is to be conscious of our own existence.

Learning is not child's play; we cannot learn without pain.

No one would choose a friendless existence on condition of having all the other things in the world.

The knowledge of the soul admittedly contributes greatly to the advance of truth in general, and, above all, to our understanding of Nature, for the soul is in some sense the principle of animal life.

Men come together in cities in order to live: they remain together in order to live the good life