[Twey]

It has constructs for a few different moods/modes[1], but no conjugation: the morphology used to form moods is borrowed from other verb forms (in your example, the bare infinitive) that were never (as far as I know!) dedicated mood conjugations.

[1]: pedantically they are ‘modes’ in the linguistic jargon, but often referred to as ‘moods’ in discussions of English grammar: linguistically a mood is the grammatical morphology used to signify a mode, which English lacks.

[thaumasiotes]

> It has constructs for a few different moods/modes[1], but no conjugation: the morphology used to form moods is borrowed from other verb forms (in your example, the bare infinitive) that were never (as far as I know!) dedicated mood conjugations.

Well, this is mixing an argument about the facts with an argument about the history.

On the facts this is a mood expressed by conjugating the verb. It obviously isn't an infinitive form because it's a finite verb. It is identical with the infinitive form, and this is a general rule of English (only observable with this one verb), but there's nothing stopping different forms from being identical, even identical by rule. In Latin the nominative and accusative case of a neuter noun are always identical.

[Twey]

Sorry, I didn't mean to confuse matters — by pulling in the etymology of the morphology I was trying to be generous to the argument. Namely, I thought there might be a chance that the bare infinitive in e.g. the conditional mood is derived from an older true mood (in the linguistic sense, i.e. a verb form that is sufficient to signify the mode), which I would consider a pretty reasonable justification for considering the bare infinitive there to be a true conditional mood, albeit one that happens to be identical to other forms. I couldn't find evidence for it though, and as far as I know it's not a common feature in other Germanic languages.

As for the syntactic argument — I think it would usually be said not to be the case due to the periphrastic nature of the construction. That is, it's not the verb conjugation itself that signifies the mode but the combination of a conjugation (that is used in a variety of different constructions) with the ‘that’ (or ‘would’, aut cetera, for other moods). As with a lot of these things, though, it's significantly a matter of the conventional definition of terms. For instance in English grammar the ‘full infinitive’ ‹to + bare infinitive› is usually considered a conjugation even though it includes an extra particle. Go figure :)

On that note, it's important to distinguish syntax from semantics: the term ‘bare infinitive’ doesn't mean that morphology is _semantically_ infinitive, the infinitive was just picked as the class representative to name that particular morphology, which is known as the ‘bare infinitive’ wherever it occurs. Ditto with ‘past participle’ and ‘present participle’, and especially ‘gerund’ (which is named after a grammatical function that doesn't even exist in English!).