se are of three kinds, mental,
bodily, and external. The bodily are described (19); then the mental,
which fall into two classes, congenital and acquired, virtue being the
chief of the acquired (20), then the external, which form with the
bodily advantages a kind of exercise-ground for virtue (21). The
ethical standard is then succinctly stated, in which virtue has chief
part, and is capable in itself of producing happiness, though not the
greatest happiness possible, which requires the possession of all three
classes of advantages (22). With this ethical standard, it is possible
to give an intelligent account of action and duty (23).

Sec.19. _Ratio triplex_: Plato has not this division, either consciously or
unconsciously, though it was generally attributed to him in Cicero's time,
so by Varro himself (from Antiochus) in Aug. _De Civ. Dei_ VIII. 4, and by
Diog. Laert. III. 56 (see R. and P., p. 195). The division itself cannot be
traced farther back than Xenocrates and the post-Aristotelian Peripatetics,
to whom it is assigned by Sext. Emp. _Adv. Math._ VII. 16. It was probably
first brought into strong prominence by the Stoics, whom it enabled more
sharply and decisively to subordinate to Ethics all else in philosophy. Cf.
esp. _M.D.F._ IV. 3. _Quid verum ... repugnans iudicando_: MSS. exc. G have
_et_ before _quid falsum_, whence Klotz conj. _sit_ in order to obviate the
awkwardness of _repugnet_ which MSS. have for _repugnans_. Krische wishes
to read _consequens_ for _consentiens_, comparing _Orator_ 115, _T.D._ V.
68, _De Div._ II. 150, to which add _T.D._ V. 21 On the other hand cf. II.
22, 91. Notice the double translations of the Greek terms, _de vita et
moribus_ for [Greek: ethike], etc. This is very characteristic of Cic., as
we shall see later. _Ac primum_: many MSS. and edd. _primam_, cf. 23, 30.
_A natura petebant_: how Antiochus could have found this in Plato and
Aristotle is difficult to see; that he did so, however, is indubitable; see
_D.F._ V. 24--27, which should be closely compared with our passage, and
Varro in Aug. XIX. 3. The root of Plato's system is the [Greek: idea] of
the Good, while so far is Aristotle from founding his system on the
abstract [Greek: physis], that he scarcely appeals even incidentally to
[Greek: physis] in his ethical works. The abstract conception of nature in
relation to ethics is first strongly apparent in Polemo, from whom it
passed into