+If you take probability and expected utility seriously—and everything we've been told about dath ilan says that that's what their Civilization is _all about_—then the quantitative extent to which the statement "It's wrong to make _X_ decision about me just because I'm _Y_" makes sense, depends quantitatively on how strongly _Y_ predicts the outcomes of _X_. Whether _Y_ is an "individual trait" like having Intelligence 18 or a demographic category like being female _does not matter_.
+
+As far as principles are concerned, anyway. But pragmatically, might it not be the case in practice, that statistical group differences are small enough, and that individual trait measurements are cheap and reliable enough, such that "don't discriminate by race or sex" is a useful _heuristic_?
+
+It's an empirical issue—but sure, very often, yes. For most jobs—especially most jobs in an industrialized Society like dath ilan—"always test the individual's aptitude, never use sex as a proxy" is a fine rule, because most jobs primarily rely on human general intelligence: there was no _dentistry_ in the environment of evolutionary adaptedness, and thus there's no reason why women or men should make better dentists.
+
+But then it's _bizarre_ that Keltham persists in his no-legal-sex-discrimination stance when his interlocutor brings up _military conscription_ as a potential counterexample. Because—as unpleasant as it is for modern folk to think about—there _was_ war in the environment of evolutionary adaptedness.
+
+Men's bodies are built for war. Men's _emotions_ are built for war. [(Males have more reproductive fitness to gain and less to lose by the prospect of risking death in a war where the victors gain mating opportunities.)](https://www.cep.ucsb.edu/papers/EvolutionofWar.pdf) The sex difference in muscle mass is [_2.6 standard deviations_](/papers/janssen_et_al-skeletal_muscle_mass_and_distribution.pdf). That means a woman as strong as the average man is at _the 99.5th percentile_ for women. That means if you just select everyone whose strength is greater than one standard deviation _below_ the male mean, you end up excluding 94.5% of women.