§26. _Quid quod si_: Goer., outrageously reads _quid quod si, si_. _Tollitur_: the verb _tollere_ occurs as frequently in this sense as αναιρειν does in Sextus. _Lux lumenque_: Bentl. _dux_ The expression _dux vitae_ is of course frequent (cf. _N.D._ I. 40, _T.D._ V. 5 and Lucretius), but there is no need to alter. _Lux_ is properly natural light, _lumen_ artificial, cf. _Ad Att._ XVI. 13, 1. _lumina dimiseramus, nec satis lucebat_, D.F. III. 45 _solis luce ... lumen lucernae_. There is the same difference between φως and φεγγος, the latter is used for the former (φεγγος ‛ηλιου) just as _lumen_ is for _lux_ (_si te secundo lumine his offendere_--_Ad Att._ VII. 26, 1) but not often _vice versa_. Trans. "the luminary and the lamp of life," and cf. Sext. _Adv. Math._ VII. 269 where the φαντασια is called φεγγος. _Finis_: so in the beginning of the _Nicom. Eth._ Aristot. assumes that the actual existence of human exertion is a sufficient proof that there is a τελος. _Aperta_: a reminiscence of the frequently recurring Greek terms εκκαλυπτειν, εκκαλυπτικος etc., cf. Sextus _passim_, and _D.F._ I. 30. _Initium ... exitus_ = αρχη ... τελος. _Tenetur_: MSS. _tenet_, the nom. to which Guietus thought to be _ratio_ above. Αποδειξις: cf. the definition very often given by Sext. e.g. _Pyrrh. Hyp._ II. 143 λογος δι' ‛ομολογουμενων λημματων (premisses) κατα συναγωγην επιφοραν (conclusion) εκκαλυπτων αδηλον, also Diog. VII. 45, λογον δια των μαλλον καταλαμβανομενων το ‛ηττον καταλαμβανομενον περαινοντα (if the reading be right). §27. _Notio_: another trans. of εννοια. _Conclusisse_: although the Greeks used συμπερασμα instead of επιφορα sometimes for the conclusion of the syllogism, they did not use the verb συμπεραινειν which has been supposed to correspond to _concludere_. It is more likely to be a trans. of συναγειν, and _conclusum argumentum_ of συνακτικος λογος, which terms are of frequent occurrence. _Rationibus progredi_: to a similar question Sextus answers, ουκ εστιν αναγκαιον τας εκεινον (the dogmatists) δογματολογιας προβαινειν, πλασματωδεις ‛υπαρχουσας (_Adv. Math._ VIII. 367). _Sapientiae ... futurum est_: for the dat. with _facio_ and _fio_ see Madv. _Gram._ 241, obs. 5, _Opusc._ I. 370, _D.F._ II. 79, and cf. 96 of this book. _Lex veri rectique_: cf. 29; the _constitutio veri_ and the determination of what is _rectum_ in morals are the two main tasks of philosophy. _Sapientique satis non sit_: so Manut. for the _sapientisque sit_ of the MSS. Halm after Dav. reads _sapientis, neque satis sit_, which I think is wrong, for if the ellipse be supplied the construction will run _neque dubitari potest quin satis sit_, which gives the exact opposite of the sense required. _Ratum_: cf. 141.