The soul has two parts, one rational and the other irrational. Let us now similarly divide the rational part, and let it be assumed that there are two rational faculties, one whereby we contemplate those things whose first principles are invariable, and one whereby we contemplate those things which admit of variation.

Even when laws have been written down, they ought not always to remain unaltered.

You should never think without an image.

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.

Now if there is any gift of the gods to men, it is reasonable that happiness should be god-given, and most surely god-given of all human things inasmuch as it is the best. But this question would perhaps be more appropriate to another inquiry; happiness seems, however, even if it is not god-sent but comes as a result of virtue and some process of learning and training, to be among the most god-like things; for that which is the prize and end of virtue seems to be the best thing in the world, and something god-like and blessed.

[I]t is rather the case that we desire something because we believe it to be good than that we believe a thing to be good because we desire it. It is the thought that starts things off.

The happy man . . . will be always or at least most often employed in doing and contemplating the things that are in conformity with virtue. And he will bear changes of fortunes most nobly, and with perfect propriety in every way.