The function of the passive diathesis is to convert the patient, usually expressed as an object, into the subject of the sentence and thus into the point of view of the utterance.
Transitive verbs with an object in the accusative, genitive or dative can be made passive; the case of the object is then converted to the nominative. The possibility of passivisation is the syntactic characteristic which distinguishes objects from satellites (i.e. adverbials):
- with the accusative: ὁράομαι ὑπό τινος, λύομαι ὑπό τινος etc.;
- with the genitive: ἄρχομαι ὑπό τινος, καταφρονέομαι ὑπό τινος, καταγελάομαι ὑπό τινος, ἀμελέομαι ὑπό τινος etc.;
- with the dative: πολεμέομαι ὑπό τινος, ἐπιβουλεύομαι ὑπό τινος, πιστεύομαι (ἀπιστοῦμαι) ὑπό τινος, φθονέομαι ὑπό τινος etc.
Verbs with an accusative of the cognate object can also be used in the passive; in this case the cognate object, which is not a real object, is simply retained:
TBX τύπτομαι πληγὴν βαρυτάτην ‘I was given a very hard blow.’
ἡ πόλις τὴν μεγίστην ἀδικίαν ἀδικεῖται ‘The city underwent a very great injustice.’
Expressing the agent
If the speaker still wishes to express who or what is the acting participant, ὑπό is used with the genitive(other prepositions are also sometimes used) or with the dative. If the predicate is in the (mediopassive) perfect, the agent is almost invariably in the dative. Note, however, that the agent is an adverbial, and thus not an obligatory constituent.
Passivisation of medial predicates
Medial predicates can be passivised as well as active predicates. As a result, the passive forms of some verbs have two possible meanings – corresponding either with the active or to the medial. An example is ἐγράφη:
- ‘it is written’ (corresponding with the active γράφει ‘he writes’);
- ‘he is accused’ (corresponding with the medial γράφεται ‘he accuses’ and γέγραμμαι ‘he has accused’).
The passive diathesis indicates that the subject has the macrorole of patient.