Since I was talking to @CovfefeAnon about whether "race" is a binary category or a smooth manifold, I thought it would be interesting to do a thesis-antithesis-synthesis in pictures.
Thesis:pic.twitter.com/hqEBmNmOBg
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Species has problems because it's not even an equivalence relation, there are birds that can mate if you go eastwards around the world but then come to a discontinuity where they can't. There are edge cases like pizzly bears, etc, and of course missing links.
It’s all so challenging and messy! 
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