ἐντυχών: aor. part. of ἐντυγχάνω, "having read" (+ dat.).
τοῦ ψεύσασθαι: "for lying" gen. of articular infin. after ἐμεμψάμην. See G. 576 for this use of the articular infin. as a gen. of cause (sometimes in conjunction with the prepositions ἕνεκα or ὑπέρ; cf. S. 2032).
ἐμεμψάμην: aor. 1 sg. dep. of μέμφομαι, "I didn't fault..."
σύνηθες ὂν τοῦτο: indir. statement after ὁρῶν, "seeing that this was (ὄν) customary" (S. 2110; G. 586).
καὶ τοῖς φιλοσοφεῖν ὑπισχνουμένοις: "even to those professing to philosophize." This is the meaning of ὑπισχνέομαι with a present infinitive.
ἐκεῖνο δὲ αὐτῶν "that thing of theirs" anticipates and so emphasizes the following εἰ clause and need not be rendered in translation.
θαυμάζω, εἰ ἐνόμιζον: "and Ι wonder that they thought," εἰ serving to soften the statement and make it more polite (a common construction after θαυμάζω: G. 654).
λήσειν: fut. infin. of λανθάνω in indir. statement after ἐνόμιζον, "that they would get away with not writing the truth."
ὑπὸ κενοδοξίας: "under the sway of (my) vanity."
τοῖς μεθ᾽ ἡμᾶς: "those after us" (i.e. posterity).
ἵνα μὴ μόνος ἄμοιρος ὦ: "so that I alone may not be portionless" (S. 2193 and 2196; G. 636 and 642).
ἐν τῷ μυθολογεῖν: "in mythmaking" (S. 2032b).
μηδὲν ἀληθὲς ἱστορεῖν εἶχον: "I had nothing true to report" (infin. used to define the meaning of the adj.: S. 2001). See also G. 565b which cites a similar phrase in Sophocles (OT 119): οὐδὲν εἶχε φράσαι "he had nothing to tell."
ἐπεπόνθειν: 1 sg. plup. of πάσχω, "I had experienced." Note that Lucian often uses pluperfects in subordinate clauses where classical authors typically use the aorist.
ἐτραπόμην: aor. mid. of τρέπω, "I turned myself."
κἄν: crasis for καὶ ἄν. The particle ἄν rarely appears with the future indicative and signals an implicit conditional assertion or has a qualifying effect on the clause (S. 1793; G. 666a; see Jerram ad loc.). Jerram cites Plato Rep. 615d3: οὐδ᾿ἂν ἥξει δεῦρο "nor will he likely come here." Lucian is similarly using ἄν here to qualify the main clause and so the sentence means: "For I will likely be telling the truth when saying this one thing, namely that I am lying." ἄν can also accompany the imperfect and aorist indicative to suggest that the action is expected or probably true (G. 461b and G. 467b).
ἄν...ἐκφυγεῖν: the potential optative becomes an infinitive after δοκῶ, "I think that I might escape...." (S. 1846).
αὐτὸς ὁμολογῶν: "by myself admitting that...."
περὶ ὧν = περὶ ἐκείνων ἅ "about the things which" as often happens, the relative pronoun has been attracted into the case of the missing antecedent (S. 2522a; G. 613b and 614). It is especially common in such situations to have the relative pronoun shift from the accus. to the gen. or dat. case.
ἔπαθον: aor. of πάσχω, "I experienced."
ἐπυθόμην: aor. of πυνθάνομαι, "I learned."
μήτε ὅλως ὄντων: "nor actually exist."
τὴν ἀρχήν: "in the first place" "at all" (S. 1600 and 1601b).
γενέσθαι δυναμένων: "are able to exist."
