In order for a war to be just, three things are necessary. First, the authority of the sovereign... Secondly, a just cause... Thirdly... a rightful intention.

It is necessary to posit something which is necessary of itself, and has no cause of its necessity outside of itself but is the cause of necessity in other things. And all people call this thing God.

The soul, which is the first principle of life, is not a body, but the act of a body; just as heat, which is the principle of calefaction, is not a body, but an act of a body.

One cannot use an evil action with reference to a good intention.

Because of the diverse conditions of humans, it happens that some acts are virtuous to some people, as appropriate and suitable to them, while the same acts are immoral for others, as inappropriate to them.

Moral science is better occupied when treating of friendship than of justice.

We can't have full knowledge all at once. We must start by believing; then afterwards we may be led on to master the evidence for ourselves.