Infinitive with deontic modality: argument (‘dynamic infinitive’)


γράμματα μαθεῖν δεῖ καὶ μαθόντα νοῦν ἔχειν

Het is nodig letters te leren en nadat je ze geleerd hebt, je hoofd erbij te houden.

Menandros, Spreuken 96

The dynamic infinitive signals a patient as a subject or object with verbs of wanting, being able and intending.

Lexical usage

Verbs of being able

δύναμαι or ἔχω ‘to be able’, ἐπίσταμαι or οἶδα ‘to know how, to be able’, μανθάνω ‘to learn how’, οἶός τε εἰμι ‘to be capable of’, πέφυκα ‘to be suitable for’ etc.

Verbs of wanting

ἀναγκάζω ‘to force’, βούλομαι ‘to want’, ἐθέλω ‘to want, agree’, ἐπιθυμέω ‘to long’, εὔχομαι ‘to wish’, τάττω ‘to impose’ etc.

Verbs of intending

ἐπιχειρέω or πειράομαι ‘to try’, κατεργάζομαι ‘to cause’, παρασκευάζομαι ‘to get ready’, ποιέω ‘to do, cause’, σπουδάζω ‘to be eager’ etc.

Verbs of obligation (with an inf. as subject)

ἀνάγκη ἐστί (μοι) or ἀναγκαῖον ἐστί (μοι) ‘it is necessary’, δεῖ (με) or χρή (με) ‘it is necessary’

Verbs of fearing and bewaring (rare)

The meaning of verbs of fearing changes when they take an infinitive. For example, δέδοικα + μή + conj. means ‘to be afraid that…’ while δέδοικα + inf. means ‘to hesitate to…, not dare to’.

Translation tips

Notice that in English, too, object clauses with similar verbs usually take the form of an infinitive. Think of sentences such as: Mieke can ski.Jantje wants to sing.Freddy tries to dance.

Syntactic behaviour

Subject in case of coreference

In general the subject of the main verb and that of the infinitive are coreferential and only the infinitive is used. If the subjects are not coreferential the subject of the infinitive takes the case which would be required for an object of that main verb. Usually this results in an accusativus cum infinitivo, but the genitivus cum infinitivo (e.g. σοῦ δέομαι ἀκολουθεῖν (Plat. Prot. 336a) ‘I ask you to follow.’) and the dativus cum infinitivo (e.g. τοῖς ἄλλοις πᾶσι παρήγγελλεν ἐξοπλίζεσθαι (Xen. Anab. 2.1.2) ‘He commanded the others to take up arms.’) also occur.

Relative time?

The state of affairs expressed by the infinitive is always posterior to that of the main verb. Consequently it exists – to use an Aristotelian term – only δυνάμει ‘in potency’; hence the name ‘dynamic infinitive’. This explains why the future infinitive only occurs as a declarative infinitive and never as a dynamic infinitive: this is because it would be unnecessary to signal posteriority in two different ways.

Use of tenses and moods

When the main verb is in the aorist the infinitive has the tendency to take the aorist too. This tendency is reversed if the main verb is in the optative. A main verb in the perfect is usually followed by a present infinitive.


Because of the resultative nature of this infinitive in some idiomatic expressions it can be anticipated by a cataphoric construction, as in τοσούτου δέω.

Example Sentences: 

δεδιέναι δὲ φασκόντων Κερκυραίων ἔχειν αὐτὸν ὥστε Λακεδαιμονίοις καὶ Ἀθηναίοις ἀπεχθέσθαι, διακομίζεται ὑπ’ αὐτῶν ἐς τὴν ἤπειρον τὴν καταντικρύ

Maar de Kerkyreeërs beweerden dat ze bang waren hem op te vangen, zodat ze door de Lakedaimoniërs en Atheners gehaat zouden worden, en hij werd door hen naar het tegenoverliggende vasteland overgebracht.

λύπην γὰρ εὔνους οἶδε θεραπεύειν λόγος

Een vriendelijk woord kan de pijn helen.

Menandros, Spreuken 319

τὸν [τε] γὰρ μέλλοντα καλῶς ἄρχειν ἀρχθῆναί φασι δεῖν πρῶτον

Men zegt dat 't nodig is dat hij die in de toekomst een goed heerser wordt, eerst overheerst moet worden.

ἐγὼ μὲν ἐβουλόμην παρὰ τούτοις εἶναι μᾶλλον πρῶτος ἢ παρὰ Ῥωμαίοις δεύτερος

Ik wou liever de eerste bij die (mannen) zijn dan de tweede bij de Romeinen.