Umm, I think you’re putting too much weight on idiomatic shorthand that’s evolved for communicating some common things very easily, and less-common ideas less easily. “Garfield is a cat” is a very reasonable and common thing to try to communicate—a specific not-well-known thing (garfield) being described in terms of a nearly-universal knowledge (“cat”). The reverse might be “Cats are things like Garfield”, which is a bit odd because the necessity of communicating it is a bit odd.
It tends to track specific to general, not because they’re specific or general concepts, but because specifics more commonly need to be described than generalities.
I don’t think there’s anything particularly idiomatic about “is a,” but that’s a side issue. What’s at issue are the underlying linguistic mechanisms. How do they work? Sure, some communicative tasks may be more common than others, and that is something to take into account. Linguistic mechanisms that are used frequently tend to be more compact than those used less frequently, for obvious reasons. Regardless of frequency, how do they work?
Umm, I think you’re putting too much weight on idiomatic shorthand that’s evolved for communicating some common things very easily, and less-common ideas less easily. “Garfield is a cat” is a very reasonable and common thing to try to communicate—a specific not-well-known thing (garfield) being described in terms of a nearly-universal knowledge (“cat”). The reverse might be “Cats are things like Garfield”, which is a bit odd because the necessity of communicating it is a bit odd.
It tends to track specific to general, not because they’re specific or general concepts, but because specifics more commonly need to be described than generalities.
I don’t think there’s anything particularly idiomatic about “is a,” but that’s a side issue. What’s at issue are the underlying linguistic mechanisms. How do they work? Sure, some communicative tasks may be more common than others, and that is something to take into account. Linguistic mechanisms that are used frequently tend to be more compact than those used less frequently, for obvious reasons. Regardless of frequency, how do they work?