Contrafactual conditions

Simple and generalizing conditional statements about past or present time both state that something is true. Contrary to fact or contrafactual statements instead assert that the protasis is not true; the apodosis states what would or would have occurred if the protasis been true. Here are examples in English.

Present time: “If they thought his speech was interesting, they would pay attention”. In fact, they find his speech boring, and are not paying attention.

Past time: “If the jury thought he was innocent, they would not have convicted him.” In fact, the jury though he was guilty, and they did convict him.

Greek makes contrafactual statements with the indicative mood, but marks them as untrue by including the particle ἄν in the apodosis. Normally, for present contrafactual conditions, the tense of both protasis and apodosis is imperfect; for past contrafactual conditions, aorist, as summarized here:

Time	Protasis	Apodosis
Present	εἰ + imperfect indicative	imperfect indicative + ἄν
Past	εἰ + aorist indicative	aorist indicative + ἄν

Examples of contrafactual conditions

εἰ μὴ ἐνόμιζoν αὐτὸν αἴτιον εἶναι, οἱ γραψάμενοι οὐκ ἂν ἐγράφοντο αὐτόν.

̣”If they did not think he was guilty, the plaintiffs would not be suing him in court.” (In fact, they think he is guilty, and they are suing him.)

εἰ μὴ ἐμοίχευσεν ὁ ᾿Ερατοσθένης τὴν γυναῖκα, οὐκ ἂν ἀπέκτεινε αὐτὸν ὁ Εὐφίλητος.

“If Eratosthenes had not committed adultery with the woman, Euphiletos would not have killed him.” (In fact, Eratoshenes did commit adultery with the woman, and we know what happened as a result.)