There is one more difficulty to be cleared up respecting virtue.  All our dispositions; and therefore all our ethical excellences, come to us in a certain sense by nature; that is, we have from the moment of birth a certain aptitude for becoming temperate, courageous, just, &c.  But these natural aptitudes or possessions [Greek:  physikai hexeis] are something altogether distinct from the ethical excellences proper, though capable of being matured into them, if intellect and prudence be superadded.  Sokrates was mistaken in resolving all the virtues into prudence; but he was right in saying that none of them can exist without prudence.  The virtues ought to be defined as, not merely ethical dispositions according to right reason, but ethical dispositions along with right reason or prudence (i.e., prudence is an ever present co-efficient).  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  Part second is a short dissertation on Pleasure, superseded by the superior handling of the subject in the Tenth Book.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. (1) God-like virtue, or reason impelling as well as directing. (2) The highest human virtue, expressed by Temperance [Greek:  sophrosynae]—­appetite and passion perfectly harmonized with reason. (3) Continence [Greek:  egkrateia] or the mastery of reason, after a struggle. (4) Incontinence, the mastery of appetite or passion, but not without a struggle. (5) Vice, reason perverted so as to harmonize entirely with appetite or passion. (6) Bestiality, naked appetite or passion, without reason.  Certain prevalent opinions are enumerated, which are to form the subject of the discussions following—­(1) Continence and endurance are morally good. (2) The Continent man sticks to his opinion. (3) The Incontinent err knowingly. (4) Temperance and Continence are the same. (5) Wise and clever men may be Incontinent. (6) Incontinence applies to other things than Pleasure, as anger, honour, and gain (I.).

The third point (the Incontinent sin knowingly) is first mooted.  Sokrates held the contrary; he made vice and ignorance convertible.  Others think that the knowledge possessed by the incontinent is mere opinion, or a vague and weak conviction.  It is objected to No. 4, that continence implies evil desires to be controlled; while temperance means the character fully harmonized.  As to No. 2, Continence must often be bad, if it consists in sticking to an opinion (II.).