κακῶς is Hermann's easy and certain correction of the MS. “καλῶς”. “"Evilly devised deeds are disclosed by speech"”: i.e. even supposing that Polyneices is harbouring ill designs, the best way to discover them is to converse with him. Cp.
,—where the bad consoience is supposed to bewray itself even before (“πρόσθεν”) investigation. With καλῶς, the words are merely “"a rhetorical generality,"” as Campbell (who retains it) says: i.e. speech is a good thing, “"for it is by speech that all man's best discoveries are revealed."” But surely we need something more relevant to the matter in hand.