-That categories are clusters in a _high-dimensional_ space is relevant because groups that overlap along any _one_ particular measurement might be much more clearly distinguishable when you look at the conjunction of many different measurements. When discussing whether a proposed recreational basketball association should be sex-segregated or not, one relevant fact that might come up during the discussion is that the sex difference in human height has a magnitude of Cohen's _d_≈1.7.
+[I use the "bimodal multivariate distribution" frame a lot—it's even in the URL—but it's actually worse: sex-specific adaptations—functional adaptations and not just shifted distributions—are a thing https://thingofthings.wordpress.com/2017/05/05/the-cluster-structure-of-genderspace/]
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+[if you have to do definitions, you go by physiology, because that's the part that's truly almost-completely-binary]
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+That categories are clusters in a _high-dimensional_ space is relevant because of a statistical phenomenon perhaps most famously elucidated in [A. W. F. Edwards's critique of Richard Lewontin's critique of the concept of _race_](https://en.wikipedia.org/wiki/Human_Genetic_Diversity:_Lewontin's_Fallacy): groups that overlap along any _one_ particular measurement might be much more clearly distinguishable when you look at the conjunction of many different measurements.
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+[TODO: the standard diagram]
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+When discussing whether a proposed recreational basketball association[ref]I'm somewhat reluctant to choose a sports example, because sporting is such a comparatively small and unimportant part of life—at least from the perspective of non-athletes—but it's a good place to start pedagogically, because merely physical sex differences are relatively uncontroversial, and it's important to avoid the distraction of unnecessarily contentious issues in the presentation of a topic that's already so prone to [motivated misunderstandings](https://en.wikipedia.org/wiki/Straw_man).[/ref] should be sex-segregated or not, one fact that might come up during the discussion is that the sex difference in human height has a magnitude of Cohen's _d_≈1.7, which is relevant because it means that insofar as selecting for good basketball players implies some degree of selection for tall people, it also implies some degree of selection for men, which would detract from the goal of creating an atmosphere where people are socially rewarded for excelling at the [high challenge](https://www.lesswrong.com/posts/29vqqmGNxNRGzffEj/high-challenge) of their chosen sport rather than for the (preëxisting, uninteresting, mostly immutable[ref]Given current technology.[/ref]) brute fact of their sex.