Sir Richard C. Jebb, Commentary on Sophocles: Oedipus Tyrannus

[220-221] οὐ γὰρ ἂν μακρὰν ...
ἴχνευον In his Syntax of the Moods and Tenses of the Greek Verb （1889）, sect. 511, Prof. Goodwin deals with this passage. His view agrees with that given in my second ed., so far as concerns two points, viz.: （1） that the chief protasis is not contained in μὴ οὐκ ἔχων: and （2） that μὴ οὐκ ἔχων is still necessarily conditional. But his analysis of the whole is simpler; it is as follows. The chief protasis is contained in the word αὐτός, “unaided,” which is equivalent to, εἰ μόνος ἴχνευον, if I were attempting to trace it alone. [I had said that αὐτός “implies the protasis”; but had taken the protasis itself to be, εἰ μὴ ἐξεῖπον, supplied from ἐξερῶ: if I had not thus spoken, —appealing to you for help.] Then, μὴ οὐκ ἔχων is equivalent to εἰ μὴ εἶχον. Now, the difficulty here seemed to be that εἰ μὴ εἶχον would imply, “but I have a clue”: whereas, in fact, he has none. [I met this by suggesting that μὴ οὐκ ἔχων expresses the fact （of his having no clue）, not simply as a fact, but as a condition, —“in a case where I had no clue”; being equivalent, not to εἰ μὴ εἶχον, but rather to ὅτε μὴ εἶχον.] Goodwin's answer is that the conditional sentence, written in full, would stand thus, —（1） and （2） denoting respectively the chief protasis, and the subordinate protasis: （1） εἰ μόνος ἴχνευον, οὐκ ἂν μακρὰν ἴχνευον, （2） εἰ μὴ εἶχόν τι σύμβολον. Now （1） is an unreal supposition （he is not tracking alone）; and that makes the whole supposition unreal. εἰ μὴ εἶχον is here a part of that unreal supposition; and therefore it can have that form, although, as a fact, he has no clue. （Suppose it to be said of a man too old for work: “If he were young, he would not be doing well, if he did not work”: εἰ νέος ἦν, οὐκ ἂν εὖ ἐποίει, εἰ μὴ ἐπόνει. The chief protasis, εἰ νέος ἦν, being unreal, makes all the rest unreal. The fact is, οὐ πονεῖ: and εἰ μὴ ἐπόνει does not imply, πονεῖ. Compressed, this would be, οὐκ ἂν εὖ ἐποίει νέος ὤν, μὴ οὐ πονῶν.） αὐτός, unaided: cp. Hom. Il. 13.729 “ἀλλ᾽ οὔπως ἅμα πάντα δυνήσεαι αὐτὸς ἑλέσθαι.”