Interpretation of Thucydides 2.48.3

Rereading some parts of Thucydides lately, I came across a passage in his account of the plague that puzzles me. One passage among many, to be sure. Or rather, I think I understand what it means, but I don’t know quite how it works.

Here is the whole relevant passage taken from the text at Perseus:

[3] λεγέτω μὲν οὖν περὶ αὐτοῦ ὡς ἕκαστος γιγνώσκει καὶ ἰατρὸς καὶ ἰδιώτης, ἀφ᾽ ὅτου εἰκὸς ἦν γενέσθαι αὐτό, καὶ τὰς αἰτίας ἅστινας νομίζει τοσαύτης μεταβολῆς ἱκανὰς εἶναι δύναμιν ἐς τὸ μεταστῆσαι σχεῖν: ἐγὼ δὲ οἷόν τε ἐγίγνετο λέξω, καὶ ἀφ᾽ ὧν ἄν τις σκοπῶν, εἴ ποτε καὶ αὖθις ἐπιπέσοι, μάλιστ᾽ ἂν ἔχοι τι προειδὼς μὴ ἀγνοεῖν, ταῦτα δηλώσω αὐτός τε νοσήσας καὶ αὐτὸς ἰδὼν ἄλλους πάσχοντας. (2.48.3)

The part giving me trouble is

μάλιστ᾽ ἂν ἔχοι τι προειδὼς μὴ ἀγνοεῖν

I believe the passage means “rather they should have knowledge beforehand /not knowing/.”
Is μὴ ἀγνοεῖν best interpreted as something like “lest they not know”?

I’ve looked at Dent’s and Jowett’s translation and Rusten’s commentary, but none helps me Rusten does note that the passage I single out is a litotes.. Any help will be appreciated.

The Dent and Jowett translations come from the Perseus Scaife viewer, and Rusten’s note is on page 182 of his commentary on Book II (CUP 1999).

I read this as follows:

ἂν ἔχοι – ἔχω + infinitive = be able to

τι here is the object of προειδὼς (or possibly adverbial, “somewhat,” “to some extent” with μὴ ἀγνοεῖν).

μὴ ἀγνοεῖν – not fail to recognize

“might be able, with some foreknowledge, to not fail to recognize [it].”

Convoluted in English, but not so in Greek.

http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3De)%2Fxw1

ἔχω . . .

III. c.inf., have means or power to do, to be able, c. aor. inf., Il.7.217, 16.110, etc.: c. pres. inf., Od.18.364, etc.; “πόλλ᾽ ἂν λέγειν ἔχοιμι” S.Ph.1047: sts. with inf. omitted or supplied from context, ἀλλ᾽ οὔ πως ἔτι εἶχε he could not, Il.17.354; οἷά κ᾽ ἔχωμεν so far as we be able, Od.15.281; “ἐξ οἵων ἔχω” S.El.1379; “ὅσον εἶχες” E.IA1452; “ὡς ἔχω” Id.Hec.614.

http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Da)gnoe%2Fw

ἀγνο-έω , :—not to perceive or recognize;

You were right to see that I was failing to take ἔχοι with ἀγνοεῖν, and ἀγνοεῖν always gives me trouble. I understand τι here as the object of προειδὼς. Now I see how it all works. Thanks a lot for your help.