James Adam, The Republic of Plato

In this difficult passage Stallbaum, who is followed by the Oxford editors, construes εἶναι with τούτων (“is one of” etc.), and regards τοῦτο ὅπερ ἐστίν as no more than “ipsam per se” (“as far as its essence is concerned,” J. and C.). This interpretation is grammatically awkward, and otherwise objectionable, inasmuch as it anticipates δίψος δ᾽ οὖν αὐτό below. Plato evidently means to present his argument in two steps: (1) Thirst, as you will agree, is something relative to drink, (2) Thirst qualified is relative to drink qualified, and thirst by itself, without qualification, to drink by itself, without qualification.

A large number of emendations has been proposed. The late Mr W. A. Gill was inclined to omit τοῦτο ὅπερ ἐστίν (Proceedings of the Cambridge Philol. Soc. XVIII p. 35), and Hartman boldly expunges the words, leaving ἔστι δὲ δήπου δίψος, as it appears to me, in a lonely and unsheltered situation. The suggestion τῶν οἵων τινος (Madvig), i.e. ‘which are such as to be that which they are relatively to something,’ is very cumbrous, and renders ἔστι δὲ δήπου δίψος far from natural. Mr Cook Wilson's defence or explanation of Madvig's proposal in the Academy no. 824 (Feb. 18, 1888) does not carry conviction to my mind. Baiter combines the conjecture of Madvig with Morgenstern's δή του for δήπου, in which case Socrates repeats his question, if ἔστι δὲ δήπου δίψος is interrogative, or, if not, answers it himself. It seems to me clear that ἔστι δὲ δήπου δίψος is intended to explain τοῦτο ὅπερ ἐστίν and nothing more. J. and C. translate “Thirst is, I imagine— Yes, said he, thirst is of drink,” remarking that “two questions are asked; before the second is completed Glauco breaks in with a reply to the first (ἔγωγε): and in πώματός γε he completes and answers the second.” I can see no occasion for so much impatience on Glauco's part. The insertion of καὶ τινός after τῶν τινός appears to me to solve all the difficulties, and the error is of a kind that frequently occurs in our oldest MS. See Introd. § 5.