It is thus abundantly evident that none but a prudent man can be good, and none but a good man can be prudent.
The virtues are separable from each other, so far as the natural aptitudes are concerned: a man may have greater facility for acquiring one than another.

But so far as regards the finished acquirements of excellence, in virtue of which a man is called _good_--no such separation is possible.

All of them alike need the companionship of Prudence (XIII.).
Book Seventh has, two Parts.

Part first discusses the grades of moral strength and moral weakness.

Part second is a short dissertation on Pleasure, superseded by the superior handling of the subject in the Tenth Book.
With reference to moral power, in self-restraint, six grades are specified.