Plato in his Republic (as I have already mentioned) assumes for his Archons the privilege of selecting (by a pretended sortition) the couples through whom the legitimate amount of breeding shall be accomplished: in the semi-Platonic commonwealth (De Legibus), he leaves the choice free, but prescribes the limits of age, rendering marriage a peremptory duty between twenty and thirty-five years of age, and adding some emphatic exhortations, though not peremptory enactments, respecting the principles which ought to guide individual choice.[167] In the same manner too he deals with procreation: recognising the necessity of imposing a limit on individual discretion, yet not naming that limit by law, but leaving it to be enforced according to circumstances by the magistrates: who (he says), by advice, praise, and censure, can apply either effective restraints on procreation, or encouragements if the case requires.[168] Aristotle blames this guarantee as insufficient: he feels so strongly the necessity of limiting procreation, that he is not satisfied unless a proper limit be imposed by positive law. Unless such a result be made thoroughly sure (he says), all other measures of lawgivers for equalising properties, or averting poverty and the discontents growing out of it--must fail in effect.[169] Aristotle also lays it down as a part of the duty of the lawgiver to take care that the bodies of the children brought up shall be as good as possible: hence he prescribes the ages proper for marriage, and the age after which no parents are to produce any more children.[170] [Footnote 167: Plato, Legg. vi. pp. 772-773-774. The wording is characteristic of the view taken by these philosophers, and of the extent to which they subordinated individual sentiment to public considerations. [Greek: kata\ panto\s ei(=s e)/stô mu=thos ga/mou; to\n ga\r tê=| po/lei dei= xumphe/ronta mnêsteu/ein ga/mon e(/kaston, a)ll' ou) to\n ê(/diston au(tô=|. phe/retai de/ pôs pa=s a)ei\ kata\ phu/sin pro\s to\n o(moio/taton au(tô=|], &c. (p. 773 B). In marriage (he says) the natural tendency is that like seeks like; but it is good for the city that like should be coupled to unlike, rich to poor, hasty tempers with sober tempers, &c., in order that the specialties may be blended together and mitigated. He does not pretend to embody this in a written law, but directs the authorities to obtain it as far as they can by exhortation. P. 733 E. Compare the Politikus, p. 311.] [Footnote 168: Plato, Legg. v. p. 740 D. [Greek: porize/tô mêchanê\n o(/ti ma/lista, o(/pôs ai( pentakischi/liai kai\ tettara/konta oi)kê/seis _a)ei\ mo/non_ e)/sontai; kai\ ga\r _e)pische/seis gene/seôs_, oi(=s a)\n eu)/rous ei)/ê ge/nesis, kai\ tou)nanti/on e)pime/leiai kai\ spoudai\ plê/thous gennêma/tôn ei)si\n], &c.] [Footnote 169: Aristotel. Politic. ii. 6, p. 1264, a. 38; ii. 7, p. 1266, b. 10; vii. 16.