If you want a good quick summary of the definition I've been implicitly using (which is in fact the basis for most actual private property law and is not at all "exotic"), "private property" is any rivalrous good--i.e., any good that, by its nature, can only be used by one person at a time: one person's use precludes use by another person. (There are edge cases--for example, multiple people can ride in a car even if it's only considered the private property of one of them--but they aren't relevant to the discussion we're having here.)

>which is in fact the basis for most actual private property law and is not at all "exotic"

What western legal system is based is such a way that it doesn’t consider IP to be private property? I am not aware of any. The notion that such a narrow definition is the basis of most actual property law runs contrary to empirical evidence.

> any good that, by its nature, can only be used by one person at a time: one person's use precludes use by another person.

> There are edge cases--for example, multiple people can ride in a car even if it's only considered the private property of one of them--but they aren't relevant to the discussion we're having here.

But that's not just edge cases. Jointly operated objects and co-habited houses make up a huge fraction of what we commonly consider to be property. I don't think you can brush this away as an edge case.

I mean, come to think it, looking at what objects currently surround me, most of them can be used by more than one person at same time.