0 in grammar, the infinitive form of a verb without the word "to": --
In the sentence "I let him go", the bare infinitive is the word "go".
The form without "to" is called the bare infinitive, and the form with "to" is called the full infinitive or "to" -infinitive.
The form without "to" is called the "bare infinitive"; the form introduced by "to" is called the "full infinitive" or "to-infinitive".
The base form is also called the bare infinitive; another common way of referring to verbs is to use the "to" -infinitive, e.g. to exist.
We could then treat the bare infinitive as unspecified (or underspecified) regarding perfectivity, although this is not explicitly stated as such in the text.
The perfective reading associated with the bare infinitive derives from the interpretation of the perception verb as stative.
When the bare infinitive is used, the activity described in the infinitival phrase is never interrupted, almost as if there is an entailment relation.
From there it was a small step for the to-infinitive to supplant the bare infinitive in other functions, notably as subject and as verb complement.
This process ultimately influenced the position of the bare infinitive, although the greatest losses were sustained by the subjunctive complement clause.
