Infinitivals

Infinitivals, or infinitival clauses, are a type of non-finite clause in which the main verb appears in the infinitive form. In English this is typically the to-infinitive (to + base form) or the bare infinitive (the base form without to). Infinitivals can function in many positions within a sentence, serving as subjects, complements, modifiers, or adverbials, and they are a common device in many languages for expressing purpose, intention, necessity, or possibility without a finite verb.

English infinitival forms come in several subtypes. The to-infinitive expresses a wide range of meanings and can be extended with aspect: the perfect infinitive (to have + past participle) and the progressive infinitive (to be + verb-ing), among others. The bare infinitive lacks to and appears after modal auxiliaries (can, may, must, will), after causative or perception verbs (let, make, help), and in certain fixed constructions. Infinitivals can also occur after adjectives or nouns, as in constructions like This is the place to visit or a decision to make.

Functions and syntax. Infinitivals can act as subjects (To err is human), direct objects (I want to go), or complements (This seems to be important). They may also modify nouns (the book to read) or clause members in more complex structures. In control constructions, an external noun phrase provides the subject of the infinitive (I asked John to leave). In raising constructions, the subject of the infinitive is linked to the main-clause subject (It seems [to be] raining).

Cross-linguistically, infinitival forms are marked differently and may use different markers or particles, but the basic idea—an non-finite verb form headed by an infinitive—is widely shared in languages.