230. The preceding chapters deal with the simple sentence, that is to say, the sentence which consists of a single verb, and the subordinate or qualifying wοrds (case forms, adverbs, prepositions) construed with it (§ 131). We have now to consider hοw this type is enlarged by means of the verbal nouns.
The infinitive and participle, as has been explained (§ 84), are in fact nouns. The infinitive is an abstract noun denoting the action of the verb, the participle a concrete noun expressing that action as an attribute. They are termed "verbal" because they suggest or imply a predication, such as a finite verb expresses (e. g. ἔρχεται ἄγων αὐτούς implies the assertion ἄγει αὐτούς), and because the words which depend upon or qualify them are construed with them as with verbs (ἄγων αὐτούς, not ἄγων αὐτῶν bringer of them). Thus they have the character of subordinate verbs, governed by the finite verb of the sentence, and serving at the same time as centers of dependent clauses.
The distinction between infinitives and other abstract substantives, and again between participles and other primitive adjectives, was probably not always so clearly drawn as it is in Greek. The infinitives of the oldest Sanskrit hardly form a distinct group of words; they are abstract nouns of various formation, used in several different cases, and wοuld hardly have been classed apart from other case forms if they had not been recognized as the precursors of the later more developed infinitive. The participles, too, are variously formed in Sanskrit, and moreover they are not the only nouns with which the construction is adverbial instead of being adnominal.
The peculiarity of the verbal nouns in point of meaning may be said to consist in the temporary and accidental character of the actions or attributes which they express. Thus πpάττειv and πρᾶξαι suggest a particular doing, momentary or progressive, at or during a time fixed by the context; whereas πρᾶξις means doing, irrespective of time; πράκτωρ one whο does, generally or permanently, a dοer; and so in other cases. The distinction is especially important for Homer. In the later language there are uses of the infinitive and participle in which they lose the verbal element, and have the character of ordinary nouns; e. g. τὸ πράττειν is nearly equivalent to πράξις, οἱ πράττοντες to πράκτορες, etc.