How can one avoid collisions with contents of extensions?

Well, on one point, kinds are the most likely thing to cause namespace problems, aren’t they? Probably followed by types of value and actions. So even if the syntax for referring to a phrase is obscure, it seems like it’s outweighed by the utility of being able to hide the names of problematic kinds.

I wonder if an approach based on Python could work. Phrases, kinds and objects could be in scope only when directly included in an extension. I think this would work a lot of the time, except for the main source file, which might need different rules. Perhaps a version of the include statement which doesn’t put anything in scope.

In my experience: properties, followed by adjectives.

An alternative:

Include Extension A by Alice.
Include Extension B by Bob.

Favour names from Extension A over names from Extension B.

If a name is defined in two extensions, the definition in the favoured one is used, and the other one’s version is not put in the including file’s scope. This sidesteps the problem of referring to things by name entirely. Of course, if B includes A, names from A would be in scope in B anyway, and whatever B says about those things (E.g. - A is Epistemology and B defines some new properties for subjects) will be true anyway.

The solution that suggests would be to have authors declare non-global name scopes explicitly, along the lines of The flying property in Chapter "Buttresses" in Architecture by Abbot Sugar is distinct from other uses of that name. (Such a line ought to be writeable either by the extension author or a story author who’s run into trouble.)

It seems that I7 would be more amenable to aliasing than qualifiers. Something like The flying property from Flight by Farmhand Zeke is also known as the departing hastily property. The flying property from Chapter "Taking Off and Landing" in Flight by George Cayley is also known as the airborne property. The flying property from Chapter "Buttresses" in Architecture by Abbot Sugar is also known as the separated from the building property.for instance.

Yes, that looks tricky.

I sense a “convergence in the force”.
Is this concept “mature” enough to be logged as a suggestion?
It would be sad to see good suggestion come to nought.

This was one of the first batch of suggestions logged on the uservoice site. It hasn’t been updated in a while, though.