Boolean logic and classical set theory. *sigh* That "paradox" goes away if you use fuzzy sets.

color_blue and I were having an extensive geek-fest about race and racism in the context of classic-vs-fuzzy sets, in which we spent a while listing a bunch of classic race-and-racism cognitive traps that had to do with modeling the world via classical sets.

If we didn't actually list this particular trap -- I don't think we did, because we were talking more about construction of identity -- it's one more for the list.