On p37 in Keller's Learn to Read Latin:

The infinitive is an abstract verbal noun in the neuter singular. It is indeclinable; that is, although it is a noun, it does not have case endings, and it has limited syntactic functions. The infinitive has the verbal properties of tense (present, perfect, or future) and voice (active or passive). As noted in Section 7, the second principal part of every verb is the present active infinitive and is regularly translated "to ." For example: movere, "to move."

Does it say that an infinitive as a noun is neuter in gender?

But on p269, is it correct that the perfect passive infinitives and the future active infinitives are periphrastics, i.e. have compound forms? Does the participle in such a periphrastic have different forms for different genders, so does such an infinitive have different forms for different genders? For example,

  • perfect passive infinitives: vocatus, a, um esse,

  • future active infinitives: vocaturus, a, um esse.

Are "vocatus, a, um esse" three infinitives with genders masculine, feminine, and neuter respectively? So can an infinitive have gender other than neuter? If all the three infinitives are neuter, when shall I use which of the three?

Or are "vocatus, a, um esse" three forms of the same infinitive, and the forms have genders masculine, feminine, and neuter respectively?


enter image description here

  • 2
    Your own quote and screenshot say that the infinitive is a neuter noun and that the participles in the periphrastic infinitives are declined for gender. What isn't clear about it?
    – Cairnarvon
    May 13, 2023 at 7:45
  • @Cairnarvon It's clearly confusing for the OP that there are two genders in play, and indeed, when the infinitive is used as a subject or object, it's not a trivial question what the gender of the declined part should be. May 13, 2023 at 12:20

1 Answer 1


It is best to distinguish between the 'true' infinitive (esse, vocare, vinci) and compound or periphrastic infinitives, which are really a construction of a participle plus the infinitive esse (vocatus esse, victuram esse).

The true infinitive is neuter:

Errare humanum est "to err is human"

The gender of the 'fake' infinitive, i.e. the combination of participle with esse, is a complicated matter, if it has a gender at all. I believe it is normally considered to be neuter as well (see below).

However, inside the fake infinitive, we find a participle. And the participle must have a gender and case, which are those of whatever word it agrees with.

Regina capta esse dicitur "the queen is said to have been captured"

Dixit filias victuras esse "he said the daughters would win"

In impersonal constructions, the neuter singular participle is used:

Audio ventum esse ad castra "I hear that *it was come to the army camp = I hear that one came to the army camp"

I believe any infinitival construction, including compound/fake infinitive and a.c.i., will be treated as neuter when needed:

Deam victuram esse bonum est "that the goddess will win is good"

Victum esse bonum est "having been defeated is good":

As in the last example, when the infinitive is meant in the general sense, without there being any primary argument for the participle to agree with, I believe the participle will normally be neuter (victum). The infinitival construction (periphrastic infinitive) as a whole is also neuter.

  • "without there being any primary argument for the participle to agree with, I believe the participle will normally be neuter (victum)" -- I'm pretty certain it's acc. masc. It is an angels-on-a-pinhead question as we will never be able to tell the difference in case of a particle, but we can tell the difference with other predicates, as in Turpe est crudelem esse &c. May 14, 2023 at 6:41
  • @SebastianKoppehel Two related points: (i) unlike ventum esse, note that crudelem esse is not an impersonal construction; (ii) unfortunately (at least for you), Cerberus exemplified the (intended) impersonal construction with an ambiguous example victum esse bonum est (he intended victum esse to be impersonal: “when the infinitive is meant in the general sense, without there being any primary argument for the participle to agree with”). His last example is ambiguous since victum esse, unlike ventum esse, can be a personal passive or an impersonal one.
    – Mitomino
    May 14, 2023 at 14:41
  • @SebastianKoppehel The ambiguity is due to the fact that one can use the verb vincere as transitive or intransitive (Cerberus intended it as intransitive here: Deam victuram esse bonum est "that the goddess will win is good"). So, on the relevant (i.e. impersonal) reading of victum esse, i.e. on the same reading that an unambiguously impersonal passive has (e.g. ventum esse ad castra), Cerberus is right when saying that the participle is neuter. It's just the case he used an unfortunate example (his last one is ambiguous) to exemplify his point.
    – Mitomino
    May 14, 2023 at 14:42
  • @SebastianKoppehel: That does look good to me as well, you're probably right, then. I tried to keep it a bit vague, was planning to look it up. I wonder now: does it perhaps also depend on the meaning of the word? Iphigeniae placuit ?nuptum esse? Scripsit libro tertio de constructione magni referre ?stabilem esse? Perhaps I feel that, when a certain type of entity comes to mind, the adjective or participle naturally attracts to it?
    – Cerberus
    May 14, 2023 at 16:38
  • 1
    … errs. And why should we not extend this idea to an example like nihil umquam ausum esse signum vitae futilis est or something? It is, of course, not grammatically impersonal, but it would not be idiomatic to supply a subject for the infinitive. May 16, 2023 at 21:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.