Pl. Ap. 33b5-6

[NateD26]

εἰ δέ τίς φησι παρ᾽ ἐμοῦ πώποτέ τι μαθεῖν ἢ ἀκοῦσαι ἰδίᾳ
ὅτι μὴ καὶ οἱ ἄλλοι πάντες, εὖ ἴστε ὅτι οὐκ ἀληθῆ λέγει.


I am not sure what is the meaning of this negative phrase here. Smyth in 2765 has ὅ τι μή/ὅσον μή, except, unless,
"are used without any verb to limit a preceding assertion".

Does Socrates mean that if it's more than one person, perhaps there's merit to his words,
but if he's the only one, "be assured that he does not speak the truth"?

[modus.irrealis]

It's clearer if you expand it to ὅ τι μὴ καὶ οἱ ἄλλοι πάντες ἔμαθον ἢ ἤκουσαν. So "if someone says that they have learned or heard something from me in private, (except for what/unless) all the others too have learned or heard".

[NateD26]

It is clearer. Thanks!