The final words of Sophocles’ Trachiniae confront modern interpreters with questions of different kinds. First, who speaks the last four lines? The manuscripts give them to Hyllus, Heracles’ son, who has been speaking since line 1264; but the ancient scholia attribute them to the chorus, adding that ‘some’ (τινες) give them to Hyllus.Footnote ¹ Second, who is the παρθένος (‘maiden’) addressed in line 1275? Iole, the girl with whom Heracles was infatuated and whom Hyllus has promised to marry? Or the chorus, addressed by Hyllus or the chorus-leader?

Spectator at the original performance could have answered these two questions. (Most scholars agree that Iole is not now on stage and so the παρθένος must be the chorus; and that it is easier for Hyllus to address the chorus-leader using the singular address than it would be for the chorus-leader to address the whole chorus in this way.) But a third may have been beyond the power of any audience member to resolve. What does Hyllus’ remark ‘as for the future, nobody sees that’ (1270) mean? Is this a resigned statement from a young man traumatized by the sudden destruction of his parents, focusing attention on the disaster of the present? Or does it stimulate the audience into thinking about what the pyre is shortly to bring: Heracles’ death, certainly, but perhaps apotheosis too?

The debate has sometimes focused on whether or not the myth was known at the time; if it was, the argument goes, Sophocles’ audience must have used it to interpret the play.Footnote ² Carolin Hahnemann has shown that Aeschylus’ Children of Heracles, a play almost certainly performed before Trachiniae, associates pyre and apotheosis; as a result, Heracles’ apotheosis must have been anticipated given the emphasis on the pyre, and, while there may be no messenger speech to that effect,

Myth is a malleable tool in the hands of the tragedians, however, and Sophocles was not obliged to follow Aeschylus’ account. Rather, whether or not his Heracles undergoes apotheosis remains unstated, unknowable – as Hyllus says with regard to the future in general. The ending's indeterminacy is not a bug but a feature, something that suits a drama which, like Oedipus the King, repeatedly emphasizes the value of epistemological doubt and the danger of incomplete knowledge.

Deliberate indeterminacy is not the only purpose behind the ending. As one scholar has put it:

Even apotheosis could not compensate for the catastrophe which has enveloped Hyllus’ family; to that extent, the question of whether Heracles becomes a god or hero, or is simply consumed in the flames, is not so much indeterminate as irrelevant. The fascination of scholarship with the ending of Trachiniae is itself testimony to Sophocles’ skill in ending at such a fruitful point; the wordsmith who conjures phrases with multiple levels of meaning (Chapter 7 above) is also the playwright who knows just when to bring a story to a close.

Remarking on the play's end, Pat Easterling comments that ‘Soph[ocles] often alludes ironically to some event outside the action in the closing moments of a play’.Footnote ⁵ Take Heracles’ words at the conclusion of Philoctetes:

According to a recent editor,

Yet can we determine the familiarity of tragic audience with such cults, especially given that the Greeks’ presence in south Italy dates back to Mycenaean times and Athens was a seafaring city? Moreover, even audience members unfamiliar with a Philoctetes cult could have taken Heracles’ words to imply one; the connection between the past change in Heracles’ fortunes and the future change in Philoctetes’ points that way, and if Sophocles could create an uninhabited Lemnos without contemporary, historical, or mythical precedent (p. 43 above), he could equally fashion a hero cult for Philoctetes. This raises the possibility of something more for Philoctetes than even a cure: heroization here feels like divine recompense for suffering, while also being an appropriate outcome for a man whose extraordinary passions go beyond the merely human.Footnote ⁷

Heracles concludes with another forward-looking reference pregnant with significance:

Neoptolemus’ impiety at the sack of Troy, in particular his killing of Priam at an altar, was a standard feature of the story. Heracles’ emphasis on the importance of avoiding impiety forces the audience to consider whether this Neoptolemus will manage to break free from that tradition and follow the hero's advice. The play gives no answer – but raising the question at all is ominous, especially given that Neoptolemus has shown such capacity both for goodness and for deceit. For all his currently sympathetic stance, the young man might soon commit serious transgressions with fatal consequences. This counterbalances the joy of the ending, producing a mixture of emotions at what had seemed a complete resolution.

Like Philoctetes, Tereus probably culminates with a deus ex machina. Fr. 589 depicts what seems to be a god passing judgement on Tereus (described as mad, ἄνους) and Procne and Philomela (said to have acted more madly still when punishing him). Even if a god's verdict, however, it is unlikely to have been the final word. True, the punishment of Tereus was grim, involving the killing and cannibalism of an innocent boy; but who could blame Procne and Philomela for avenging the unprovoked outrage which Tereus committed against Philomela? This too, then, may be a deus ex machina speech which leaves matters unresolved.

Allusion beyond a drama's conclusion can have moving consequences:

Polynices anticipates his own death; yet his sister cannot persuade him to turn back. These moving words, presumably accompanied by their final embrace, are followed up at the very end. After Oedipus’ death, Antigone begs Theseus to let her and Ismene return home to check their brothers’ conflict; Theseus readily agrees (1769–76). Yet for anyone familiar with Antigone, Antigone's desire to return to Thebes sounds ill-omened: since there Antigone's involvement in the aftermath of the assault on Thebes leads to her own unnecessary death. Her affection for Polynices itself conjures memories of the earlier play, where her devotion to her brother is so fatally clear. So, although the chorus's concluding words ‘But cease, and do not stir up lament any more; for these things hold completely fast’ (ἀλλ᾽ ἀποπαύετε μηδ᾽ ἐπὶ πλείω | θρῆνον ἐγείρετε· | πάντως γὰρ ἔχει τάδε κῦρος, 1777–9) seem to mark an end, an audience can only anticipate worse to come, as they ponder how ‘for all his prophetic power…Oedipus came to destroy the daughter he loved along with the sons he hated’.Footnote ⁸

Electra ends with a furious exchange between Orestes and Aegisthus:

The drama ends with Orestes’ vengeance to the fore; but in this exchange Aegisthus gets the better lines. Killing an offender in the location where he originally committed his crime was a standard feature of ancient vengeance, but Aegisthus’ questions as to why his killing needs to be performed in darkness, and whether the house needs to see all the ills of his family, including future ones, must have affected the spectators’ view of the action about to take place. ‘Just vengeance is finally accomplished, but at the cost of an ugly act, whose ugliness will not go away; the avengers are cheated of their triumph by the bitterness of success: all is not well within the house.’Footnote ⁹

Finally, Oedipus the King, whose conclusion has undergone particular scrutiny; indeed, no passage from Greek tragedy has recently been subject to such sustained philological analysis. The authenticity of the ending (1424–1530) was first questioned in the early eighteenth century by Jean Boivin de Villeneuve;Footnote ¹⁰ doubts have been repeatedly expressed since,Footnote ¹¹ including recently when Roger Dawe incorporated this massive deletion into the second edition of his Cambridge Greek and Latin Classics commentary.Footnote ¹² After a subsequent article attempted to refute Dawe's case,Footnote ¹³ David Kovacs opened up another front, arguing that the interpolation began in line 1468, a hypothesis criticized by Alan Sommerstein and later reasserted by Kovacs.Footnote ¹⁴ More recent editions of the play excise less than Dawe's: Manuwald's takes out 1515–30, or all of the closing trochaic tetrameters, and mine just 1524–30, the closing choral lines whose many linguistic faults are generally agreed to exclude Sophoclean paternity.Footnote ¹⁵ It is a remarkable sign of the textual instability of Sophocles’ plays as we have them that even a matter as basic as where one of the plays ended is still unresolved.

The persistent debate reflects in part the boldness of the play's conclusion.Footnote ¹⁶ Having given every indication that Oedipus would end the play by departing from the city,Footnote ¹⁷ Sophocles instead leaves him confined in the house, waiting for news from Delphi. This creates surprise in what might have been a predictable ending, and also evokes themes and ideas prominent earlier: the play which began with Oedipus pitying his people and striving to heal their pain ends with him as a figure of pity himself, yet also pitying the daughters whose lives his own actions destroyed. At the start his compassion was directed toward metaphorical children, the people of Thebes; by its end he must focus on his actual offspring, stripped as he is of wider responsibilities. On both occasions he caused the suffering; unaware of this at the start, he knows it only too well by the end. The conclusion also emphasizes how so much is unresolved, in particular Oedipus’ future position.Footnote ¹⁸ The grand gesture of the king leaving the city would be exploited in Seneca's Oedipus; it seems almost demanded by the logic of the myth, with Oedipus the pharmakos or scapegoat removed for the good of the city. Yet Sophocles, master of his material, holds Oedipus back instead of expelling him, denying his character the dramatic exit, and the resolution, which he craves.

Why does extant Sophoclean drama contain so many unresolved endings? An answer may lie in the development of tragedy. Whereas the writer of a connected trilogy, like Aeschylus, had three plays to draw out, explore, and ultimately resolve the problems which gave the work its forward momentum, a dramatist such as Sophocles, who usually worked within the confines of a single play (p. 000 above), had less scope to do this. So, rather than effecting a speedier resolution to tragic dilemmas, Sophocles seems to have embraced the idea of not bringing his tragedies to a full resolution at all, or persistently undermining what resolution the ending does contain. The connected trilogy afforded three stopping points (four if the satyr-play is included), two of which must be unresolved so as to provide forward motion into the succeeding tragedy. Sophocles apparently took the unresolved ending from the earlier plays of the trilogy and employed it in plays whose story was not continued in some later drama. Whether or not he was the first to do this, the high number of open endings among the plays suggests that he adopted this technique as his own. As a result, Sophoclean tragedy was, and remains, resistant to the tidy conclusion, to the neat drawing-together of threads.