Necessity

Verbals in -τέος, -τέᾱ, -τέον express necessity (cp. the Lat. gerundive in -ndus), as δοτέος that must be given, παιδευτέος educandus.

Unfulfilled Obligation (Propriety, Possibility).—With the imperfect indicative of impersonal expressions denoting obligation, propriety, necessity, or possibility, the action of a dependent infinitive is usually not realized. (Examples 1775-1776.)

Such expressions are ἔδει, χρῆν (or ἐχρῆν), προσῆκε, καιρὸς ἦν, ἄξιον ἦν, εἰκὸς ἦν, δίκαιον ἦν, αἰσχρὸν ἦν, ἐξῆν, καλῶς εἶχεν, verbals in -τόν or -τέον with ἦν, etc.

a. For the use of these expressions (also with ἄν) in the apodosis of unreal conditions, see 2313, 2315.

Past Potential.—The past tenses (usually the aorist, less commonly the imperfect) of the indicative with ἄν (κέν) denote past potentiality, probability (cautious statement), or necessity: ὃ οὐκ ἂν ᾤοντο which they could not have expected T. 7.55, τίς γὰρ ἂν ᾠήθη ταῦτα γενέσθαι; for who would have expected these things to happen? D. 9.68 (note that ἄν does not go with γενέσθαι by 1764), ἔγνω ἄν τις one might (could, would) have known X. C. 7.1.38, ὑπό κεν ταλασίφρονά περ δέος εἷλεν fear might have seized even a man of stout heart Δ 421.

a. This is especially frequent with τὶς and with the ideal second person (cp. putares, crederes): ἐπέγνως ἄν you would (could, might) have observed X. C. 8.1.33.

b. The potential optative (1829) in Homer refers also to the past.

Potential Optative.—The potential optative with ἄν states a future possibility, propriety, or likelihood, as an opinion of the speaker; and may be translated by may, might, can (especially with a negative), must, would, should (rarely will, shall). So in Latin velim, videas, cognoscas, credas.

γνοίης δ᾽ ἂν ὅτι τοῦθ᾽ οὕτως ἔχει you may see that this is so X. C. 1.6.21, ἅπαντες ἂν ὁμολογήσειαν all would agree I. 11.5, ἡδέως ἂν ἐροίμην I (would gladly ask) should like to ask D. 18.64, οὐκ ἂν λάβοις thou canst not take S. Ph. 103, λέγοιμ᾽ ἂν τάδε I will tell this A. Supp. 928. The second person singular is often indefinite (one), as γνοίης ἄν (cognoscas) = γνοίη τις ἄν.

a. The potential optative ranges from possibility to fixed resolve. The aorist optative with ἄν and a negative is very common.

b. When stress is laid on the idea of possibility and power, necessity and obligation, Greek uses δύναμαι, δεῖ or χρή with the infinitive (statement of fact).

c. The potential optative with ἄν is also used in dependent sentences; in purpose clauses (2202 b), in object clauses after verbs of effort (2216) and verbs of fearing (2232), in causal clauses (2243), in result clauses (2278), in the apodosis of conditional (see 2356) and conditional relative sentences (2566). In indirect discourse the infinitive with ἄν or the participle with ἄν may represent the optative with ἄν (1845 ff.).

The infinitive follows many verbs, especially such as denote ability, fitness, necessity, etc. (and their opposites).

οὐκέτι ἐδύνατο . . . βιοτεύειν he was no longer able to live T. 1.130, νεῖν ἐπιστάμενος knowing how to swim X. A. 5.7.25, πεφῡ́κᾱσί τε ἅπαντες . . . ἁμαρτάνειν and all men are by nature prone to err T. 3.45, μανθάνουσιν ἄρχειν τε καὶ ἄρχεσθαι they learn how to govern and be governed X. A. 1.9.4; also after the impersonals of 1985.

a. ἔχω I can is derived from the meaning I have especially with a verb of saying. Thus, Διὸς πλᾱγᾱ̀ν ἔχουσιν εἰπεῖν they can proclaim a stroke of Zeus A. Ag. 367.