[Tmpod]

You're right, the USA is huge and highly diverse as well. Yet, I'd still say it's more of a unit than the EU is, in many ways, and especially more so than "Europe". That's what I meant with "Europe is not a unit like the USA is"; not that the USA has absolute unity and Europe has none. But I may be wrong about the USA's cohesion on a deeper level, I've never been there and only see it through an outsider's lens.

[citadel_melon]

Determining whether Europe or the US is more diverse is like asking the question: “are there more doors or wheels in the world?” To answer such a question, you need to over qualify your definition to the point where the final answer is meaningless and thus doesn’t act as a useful premise for any argument. Maybe there exists a perfect definition of diversity that would be useful, but still in this unlikely case, the question would require so much non-existent data that answering it would be exorbitantly expensive.

Respectively, anyone who claims to know if the US or Europe is more diverse is making as fallacious of an argument as someone saying that they know if there exists more doors or wheels in the world. In both examples, they likely over-qualify their definitions. If they somehow aren’t overqualifying their definitions, they certainly do not have the necessary data to back up their claims.

[fragmede]

How does qualifying the definition go from being fine, to being overqualifying? If you want to compare two things, you do have to define what those two things are in the first place. The answer is wheels, because of the many small ones. Toys, office chairs, and luggage. Vs an estimatable quantity of doors because we know roughly how many homes there are in the world. The final answer doesn't become meaningless simply because you've defined the problem concretely. There are many debates to be had, but as to the question of is Europe or America more diverse, the proper response, thus, is: by what metric?

[citadel_melon]

You are playing the doors/wheels game naively because you have already overly qualified your definition of what is a door and what is a wheel without realizing it.

Have you considered for example if ball bearings wheels? Are gears and sprockets just notched wheels? Do cabinet doors count as doors? Do windows count as doors? Do microchip logic gates count as doors? What about pet flaps? Heart valves? Etc etc.. One’s definition of wheel/door can not account for these and countless other grey areas while still being useful.

Maybe one can strain oneself to find a definition that works like how people strain themselves to find a definition of sandwich that includes hoagies but disclude hotdogs, or one can just work backwards from one’s crude definitions and misclassify many objects.

Regardless, there is no right answer if there are more doors or more wheels. The question is too vague. Something that may be possible to answer is a more qualified question like “are there more human-sized doors or wheels for human transportation.” But again now the question is not our original question. And even if we were satisfied with just answering this more qualified question, we would have trouble answering it without a lot of money or making bad assumptions like the distributions of doors/wheels in a given house is uniform across all cities/towns/suburbs/houses etc..