English Grammar - Infinitive

In traditional descriptions of English, the infinitive is the basic dictionary form of a verb when used non-finitely, with or without the particle to. Thus to go is an infinitive, as is go in a sentence like "I must go there" (but not in "I go there", where it is a finite verb). The form without to is called the bare infinitive, and the form with to is called the full infinitive or to-infinitive.

English

See also: English verbs

 

Regarding English, the term "infinitive" is traditionally applied to the unmarked form of the verb when used as a non-finite verb, whether or not introduced by the particle to. Hence sit and to sit, as used in the following sentences, would each be described as an infinitive:

• I can sit here all day.
• I want to sit on the other chair.

The form without to is called the bare infinitive; the form introduced by to is called the full infinitive or to-infinitive.

The other non-finite verb forms in English are the gerund or present participle (the -ing form), and the past participle – these are not referred to as infinitives. Moreover the unmarked form of the verb is not regarded as an infinitive when it is used as a finite verb: as a present indicative ("I sit every day"), subjunctive ("I suggest that he sit"), or imperative ("Sit down!"). (For some irregular verbs the form of the infinitive coincides additionally with that of the past tense and/or past participle, as in the case of put.)

Certain auxiliary verbs are defective in that they do not have infinitives (or any other non-finite forms). This applies to the modal verbs (can, must, etc.), as well as certain related auxiliaries such as the had of had better and the used of used to. (Periphrases can be used instead in some cases, such as (to) be able to for can, and (to) have to for must.) It also applies to the auxiliary do, as used in questions, negatives and emphasis as described under do-support. (Infinitives are negated by simply preceding them with not. Of course the verb do when used as a main verb can appear in the infinitive.) However, the auxiliary verbs have (used to form the perfect) and be (used to form the passive voice and continuous aspect) both commonly appear in the infinitive: "I should have finished by now"; "It's thought to have been a burial site"; "Let him be released"; "I hope to be working tomorrow."

A matter of controversy among prescriptive grammarians and style writers has been the appropriateness of separating the two words of the to-infinitive (as in "I expect to happily sit here"). For details of this, see split infinitive. Modern linguistic theories typically do not consider the to-infinitive to be a distinct constituent, instead regarding the particle to as operating on an entire verb phrase; so, to buy a car is parsed as to [buy [a car]], not as [to buy] [a car].

Uses of the infinitive

The bare infinitive and the to-infinitive have a variety of uses in English. The two forms are mostly in complementary distribution – certain contexts call for one, and certain contexts for the other; they are not normally interchangeable, except in occasional instances such as after the verb help, where either can be used.

The main uses of infinitives (or infinitive phrases) are as follows:

• As complements of other verbs. The bare infinitive is used as complement of the dummy auxiliary do, most modal auxiliary verbs, verbs of perception such as see, watch and hear (after a direct object), and the verbs of permission or causation make, bid, let, and have (also after a direct object). The to-infinitive is used after many intransitive verbs such as want, aim, like, fail, etc., and as a second complement after a direct object in the case of verbs such as want, convince, aim, etc.
• In various particular expressions, such as had better and would rather (with bare infinitive), in order to, as if to, am to/is to/are to.
• As a noun phrase, expressing its action or state in an abstract, general way, used as the subject of a clause or as a predicative expression: "To err is human"; "To know me is to love me". The bare inifinitive can be used in such sentences as "What you should do is make a list." A common construction with the to-infinitive involves a dummy pronoun subject (it), with the infinitive phrase placed after the predicate: "It was nice to meet you."
• Adverbially, to express purpose, intent or result – the to-infinitive can have the meaning of "in order to ..." or "so as to ...".
• As a modifier of a noun or adjective. This may relate to the meaning of the noun or adjective ("a request to see someone"; "keen to get on"), or it may form a type of non-finite relative clause, as in "the man to save us"; "the method to use"; "nice to listen to".
• In elliptical questions (direct or indirect): "I don't know where to go." After why the bare infinitive is used: "Why reveal it?"

In many (though not all) uses of the to-infinitive, it can be given a subject using the preposition for: "For him to fail now would be a great disappointment"; "[In order] for you to get there on time, you'll need to leave now."

The infinitive is also the usual dictionary form or citation form of a verb. The form listed in dictionaries is the bare infinitive, although the to-infinitive is often used in referring to verbs or in defining other verbs: "The word 'amble' means 'to walk slowly'"; "How do we conjugate the verb to go?"

For further detail and examples of the uses of infinitives in English, see Bare infinitive and To-infinitive in the article on uses of English verb forms.