ἄν: always stands with the aor. inf. after verbs signifying to hope, expect, promise, suppose, and the like, when the governing verb does not make the reference to the fut. unmistakable. Cf. 318 a, 348 d, 353 b. See GMT. 22, 2, N. 3; 41, 3.
16 μόνος: is const. with οἴει, being attracted into agreement with the subj. of the latter, while, according to the sense, we should expect μόνον agreeing with the subj. acc. of διαλέγεσθαι. So regularly in οἴομαι δεῖν, χρῆναι and similar expressions, the const. is unaffected by the impers. inf. Cf. Isocr. IX. 30 οὐχ ἡγήσατο δεῖν χωρίον ὀχυρὸν καταλαβὼν περιιδεῖν, Dem. XXI. 17 αὐτὸς διδάσκειν ᾤετο δεῖν τὸν χορόν. See G. 138, N. 8; H. 944; 940.
Protagoras always displays his art in long and ornate discourses, aiming at thoughts which are striking rather than true. He does this here, in what he boastfully says of the antiquity of the sophistical art. The support for his statement he finds in the fact that all whom he quotes were eminent in the wisdom of practical life, which he maintains to be the essence of his own art. Socrates afterwards shows (cf. 342a ff.) that this method of grouping may be made very convenient. The supposed προμήθεια of Socrates serves perfectly the end of enabling Protagoras to declare his own fearlessness and to eulogize his profession. In fact, however, when he had offered to Socrates the decision as to the presence of others at the colloquy, Socrates had disclaimed any preference.
See on 315 a.
οἰκείων . . . νεωτέρων: note the ὁμοιοτέλευτα.
