xix.), we shall in obedience to reason necessarily endeavour to bring about that men should live in obedience to reason.

But the good which every man, in so far as he is guided by reason, or, in other words, follows after virtue, desires for himself, is to understand (IV.

xxvi.); wherefore the good, which each follower of virtue seeks for himself, he will desire also for others.

Again, desire, in so far as it is referred to the mind, is the very essence of the mind (Def.

of the Emotions, i.); now the essence of the mind consists in knowledge (II.