What function does the infinitive serve in the following sentence?
It is too early to talk about that thing.
1 Answer
It is too early to talk about that thing.
The function of the infinitival clause is that of indirect complement of the adjective "early". It's indirect because although it is complement of the head "early", it is licensed by the "too" that modifies "early". In other words, although it is licensed by "too" it is a dependent of "early" not directly of "too".
"Too" expresses a degree that exceeds the maximum or upper bound consisting, in this case, of the maximum at which one can talk about that thing. It is early to a degree higher than the maximum at which one can or should talk about that thing: it follows that one can't or shouldn't talk about that thing now, hence it has a negative implication.
AdjtoVPis a negative; the construction means 'soAdjthat notVP', though of course that idiom requires a tensed VP and not an infinitive. Hence, It's too early to talk about that means we should not talk about that now. As for the function of the infinitive, it's what gets negated by too; what other functions do you have to choose from?