a dialogue of death

Sophocles Trag., Electra  1477-78
Orestes to Aegisthus
 Οὐ γὰρ αἰσθάνῃ πάλαι
ζῶν τοῖς θανοῦσιν οὕνεκ' ἀνταυδᾷς ἴσα;

Orestes is speaking to Aegisthus who is just now discovering that Orestes is not only alive but present and speaking with him. We see γὰρ introducing a question where the preceding context supplies the grounds for an inference implied in the question[1]. This takes the form of a question but it is really a statement. The adverb πάλαι indicates time just past “for some time now” (J.H. Kells). The verb αἰσθάνῃ takes an object clause introduced by οὕνεκα with the verb ἀνταυδᾷς[2]. Sophocles stacks the arguments for ἀνταυδᾷς not only in front of the verb but in front of the conjunction οὕνεκα. Some scholars amended the mss reading ζῶν τοῖς to ζῶντας by conjecture which leaves us with two participles ζῶντας an accusative plural and θανοῦσιν a dative plural. Kells reads ζῶντας rendering “Why do you not perceive that you have for some time now been addressing living men as though they were dead?”  If the mss reading ζῶν τοῖς is retained then the participle ζῶν applies to Aegisthus “you the living are speaking [face to face] with the dead” where τοῖς θανοῦσιν refers to those who are residents of the nether world, an ironic reference to Orestes, a double irony since Orestes who was considered dead is now alive and Aegisthus who was alive and exulting over Orestes’ death is now as good as dead. 

[1] Guy Cooper compares this use of γὰρ to ἄρα, Greek Syntax vol. 4, 2:69:14:6:H.
[2] Guy Cooper, Greek Syntax vol. 3, 2:55:7:12:A, p. 2570.