Infinitival constructions

There are six major standard combinations of the three main grammatical categories involved:

• Plain vs perfect (temporal viewpoint)

• Progressive vs non-progressive (aspect)

• Active vs passive (voice)

In practice, these are the only combinations that are normally recognised as productive infinitival VP structures:

• Plain: leave

• Progressive: be leaving

• Passive: be left

• Perfect: have left

• Perfect progressive: have been leaving

• Perfect passive: have been left

These six constructions characterise the internal structure of an infinitival VP, regardless of it’s licensor.

The six-way distinction is entirely inside the VP.

Six basic infinitival VP constructions

Construction	Form	General rule for predicates
Plain infinitival	plain-form verb	Almost any verb: dynamic or stative
Progressive infinitival	be + gerund-participle	Normally dynamic predicates (events/processes), not ordinary stative predicates
Passive infinitival	be + past participle	Passivisable verbs (typically transitive verbs)
Perfect infinitival	have + past participle	Almost any verb; expresses anteriority
Perfect progressive infinitival	have + been + gerund-participle	Normally dynamic predicates with duration or internal development
Perfect passive infinitival	have + been + past participle	Passivisable verbs; expresses anterior passive situation

Important

Infinitival constructions allow a non-finite clause to express a situation while adding different kinds of grammatical viewpoint.

• The plain infinitival presents the situation neutrally

• The progressive presents it as ongoing or internally unfolding

• The perfect places it before a reference time

• The passive changes the perspective by presenting the affected participant rather than the agent as the subject

These meanings can combine, as in perfect progressive and perfect passive constructions.

Predicate compatibility

• Plain → unrestricted.

• Progressive → requires a predicate compatible with the progressive.

• Passive → requires a predicate that allows passive formation.

• Perfect → unrestricted; adds anteriority.

• Perfect progressive → progressive compatibility + perfect anteriority.

• Perfect passive → passive compatibility + perfect anteriority.

Predicate compatibility examples

Example	Why restricted/unlikely
He may be knowing	know is a stative predicate and normally resists the progressive. The progressive presents a situation as unfolding internally, which conflicts with the usual meaning of know.
He may have been knowing	Same issue: the progressive component (been knowing) is incompatible with ordinary know. The perfect itself is fine (may have known).
He may be resembling	resemble is normally a stative relation and does not naturally describe an ongoing process. Also, it is not normally passivisable, so be resembled is not a good passive.
He may have been resembling	Same progressive issue. The perfect component is fine (may have resembled), but the progressive component is problematic.

Ungrammatical predicates examples

Example	Why restricted/unlikely
He may be knowing	know is a stative predicate and normally resists the progressive. The progressive presents a situation as unfolding internally, which conflicts with the usual meaning of know.
He may have been knowing	Same issue: the progressive component (been knowing) is incompatible with ordinary know. The perfect itself is fine (may have known).
He may be resembling	resemble is normally a stative relation and does not naturally describe an ongoing process. Also, it is not normally passivisable, so be resembled is not a good passive.
He may have been resembling	Same progressive issue. The perfect component is fine (may have resembled), but the progressive component is problematic.

Licensing environments

Licensing environment	Example
To-infinitival complement	He wants to leave.
Bare infinitival complement after causative verb	She made him leave.
Bare infinitival complement after perception verb	I saw him leave.
Bare infinitival complement after let	Let him go.
Bare infinitival complement after help	She helped him (to) finish.
Purpose adjunct	He left to buy some food.

Role of “be”

Construction	Role of be
Plain infinitival	Lexical/copular be (when present): may be tired
Progressive infinitival	Auxiliary be: may be sleeping
Passive infinitival	Auxiliary be: may be arrested
Perfect infinitival	No be: may have left
Perfect progressive infinitival	Auxiliary be (as been): may have been sleeping
Perfect passive infinitival	Auxiliary be (as been): may have been arrested

Important

Do is not part of these six infinitival constructions because it does not mark aspect or voice.

Unlike be (progressive/passive) and have (perfect), auxiliary do is used mainly in finite clauses for negation, questions, and emphasis:

He does not leave. Does he leave? He does leave.

It therefore does not function as an infinitival auxiliary:

He must do leave. Let him do leave.

Do can occur in an infinitival clause only as a lexical verb:

He wants to do the work.

Infinitival clause structure

Infinitival clauses are non-finite clauses whose verbs lack primary tense.

Their internal VP structure may include aspectual and voice auxiliaries (be and have), forming constructions such as plain, progressive, passive, perfect, and combinations of these.

They share four general properties:

• Non-finiteness: The verb does not carry primary tense.

• No primary past tense: Anterior time is expressed through the perfect (have + past participle).

• Auxiliary-based structure: Aspect and voice are expressed through be and have.

• Licensing by an external element or function: infinitival clauses occur in environments such as modal constructions, complements, and purpose clauses.

In many complement constructions, an infinitival clause forms a catenative chain, where a preceding verb or auxiliary selects a non-finite complement:

He wants to leave. He may leave. She made him leave.

Important

Infinitival clause = licensing environment + infinitival VP structure

Examples:

• may + have left

• want + to leave

• make + leave