How would you know aliens don't share the same 'mundane facts'?

It seems entirely possible.

We could argue about the definitions of "mundane" and "alien" but I've observed the same thing about HN comments and it's not specific to PG essays so that's why I said it is a mundane fact of human psychology.

They very well could, but it is plausible that they do not.

Certain facets of mathematics however, it is not plausible that they do not share.