Great men are always of a nature originally melancholy.

Prudence as well as Moral Virtue determines the complete performance of a man's proper function: Virtue ensures the rightness of the end we aim at, Prudence ensures the rightness of the means we adopt to gain that end.

It is of itself that the divine thought thinks (since it is the most excellent of things), and its thinking is a thinking on thinking.

We may assume the superiority ceteris paribus of the demonstration which derives from fewer postulates or hypotheses - in short, from fewer premises.

We are what we frequently do.

What is the highest of all goods achievable by action? ...both the general run of man and people of superior refinement say that it is happiness ...but with regard to what happiness is they differ.

The virtue of a faculty is related to the special function which that faculty performs. Now there are three elements in the soul which control action and the attainment of truth: namely, Sensation, Intellect, and Desire. Of these, Sensation never originates action, as is shown by the fact that animals have sensation but are not capable of action.