What are infinitives and what is their role?

Answer 1

The infinitive is one form of a verb.

The easiest way to understand which form of the verb it is, is to think "Where would I look up this word in a dictionary?"

So, if you wanted to look up the word "judging" in the sentence "Judging by its flavor I'd say this milk has gone off" you would look up "judge". Likewise for "saw" in the sentence "We saw the new plane fly over today" you would have to look under "see"; if you were lucky your dictionary might list under "saw" one entry like "past tense of SEE", the capital letters meaning go have a look under that word.

There is a popular belief that an English infinitive must include the little word "to", as in "to judge, to see" and so on. Nowadays "to" is, in this situation, referred to as a particle. It often accompanies an infinitive:

I like to look at the sea.

but it does not always:

Did you see me leap over that gate?

Let me speak.

Putting "to" in front of a verb is another good way to identify an infinitive: we cannot say "to judging" or "to saw".

The myth that "to" is part of the infinitive is behind that curious "rule" that there is something called a "split infinitive" and that writing or even speaking one is a serious social disgrace!

The split infinitive was, according to this analysis, a construction consisting of to + a word (often an adverb) + a verb (in fact, the true infinitive). An example: "I like to thoroughly mix the ingredients at this stage". This sentence could be reworded "to mix the ingredients thoroughly", but there are times when this kind of rearrangement lacks impact, clarity, or both. The famous Star Trek phrase "To boldly go..." may have helped bury that odd prohibition, which was, in any case, always at odds with the spirit of the evolution of modern English.

An infinitive is not inflected; it does not change its ending. It does not have tense (this is what "infinitive" means: the word is not finite). An infinitive can act as a noun ("To see is to understand"), but cannot be the only verb in the sentence (in the previous example, the main verb is "is").

It is not possible to state a water-tight definition of the role of an infinitive, because infinitives, with and without "to", pop up in a variety of syntactical situations, and only familiarity with a language will acquaint you with them all.