An Addendum to the Post on Alignments

So, there was a slightly peculiar notion present in the previous post - viz. 'intransitive object'. Clearly this is not a well-defined thing!

Under what circumstances could we consider an object to be intransitive as well as an object? This will be somewhat language-specific, but it helps to consider what kinds of things could lead to such a situation.

Of course, the terminology "intransitive object" is not widely used - I have in fact never seen it, and thus only use it as a very vague proto-idea here.

1. Passives
We could have the object remain object-like even after passivization. This happens in Finnish, where the passive is more like a zeroth person than a voice (although it is distinct enough from the persons too not to really qualify as one of them). If the object of a passive can be coordinated with the objects of active verbs, and not with other subjects, this would seem one rather likely contender. Of course, purely entirely omitted subjects - such as when making general utterances such as this one - could also qualify.

2. Imperatives?
These qualify in Finnish, although even there Finnish does have number congruence for the subject.

3. How about verbs with pro-dropped subjects?
Somehow, this does not seem all that justified, yet it's tantalizingly close.

4. Quirky case subjects
This is the case in Finnish - non-nominative subjects turn the verb sorta-intransitive-with-an-object.

5. Objects of verbs where the connection to the subject is sort of weak by means of being quite embedded phrases.

6. Certain kinds of switch-reference - I'd imagine 'same subject' would tend to be more likely to be parsed as having an intransitive object?

Not a very coherent post, I know. Obviously, this creates a sort of "split-O" situation which only appears in the "anti-ergative" (and the loony unattested system) system - but a language could imaginably have an anti-ergative subsystem as well as a regular nom-acc or ergative subsystem: maybe indefinite objects are anti-ergative, whereas definite objects are accusative - thus giving us:

I bought house.acc (indefinite or definite house
buying house.NOM is a big decision (indefinite house)
opening door.ACC is impossible (definite door)

This essentially takes Turkish-style Differential Object Marking and restricts where it can appear, by having different types of objects act differently under different circumstances. However, maybe it could be affected by properties of the verb instead? Say, having it be lexically determined instead of determined by TAM - so buy takes anti-ergative, sell takes nominative?