+I've addressed this class of argument at length (about 7500 words) in a previous post, ["The Categories Were Made for Man to Make Predictions"](http://unremediatedgender.space/2018/Feb/the-categories-were-made-for-man-to-make-predictions/), but to summarize _briefly_, while I _agree_ that categories can be defined in many ways to suit different cultural priorities, it's also the case that not all possible categories are equally useful, because the cognitive function of categories is to group similar things together so that we can make similar predictions about them, and not every possible grouping of entities yields a "tight" distribution of predictions that can be usefully abstracted over.
+
+A free-thinking biologist certainly _could_ choose to reject the othrodoxy of grouping living things by ancestry and reproductive isolation and instead choose to study living things that are yellow, but their treatises would probably be difficult to follow, because "living things that are yellow" is instrinsically a much less cohesive subject matter than, say, "birds": experience with black crows is probably going to be _more_ useful when studying yellow canaries than experience with yellow daffodills—even if, _in all philosophical strictness_, there are a million things that these categories could have been drawn around, and who can say but that some other culture might have chosen color rather than ancestry as the true determinant of "species"?
+
+It is of course true that different cultures will place different emphases and interpretations on various ways in which people can differ: being prepubescent or being a parent might have special significance in some cultures that outsiders could never understand. But to say that prepubescents might as well be a "gender"—well, at this point I must confess that I'm really not sure what this "gender" thing is the author is trying to talk about.
+
+And I guess that's the problem. People who assume a TERFy definition of _woman_—like, say, the authors of the Mirriam–Webster dictionary [("noun, **1.a.**, an adult female person")](https://www.merriam-webster.com/dictionary/woman)—generally aren't trying to invalidate anyone's "gender"; they're trying to talk about _biological sex_ using simple, universally-understood words. Biological sex is obviously not the only category in the world—in a lot of situations, you might care more about whether someone has living children—or for that matter, whether an organism is yellow—than what sex it is.
+
+But when people _do_ want to talk about sex—when they want to carve reality along that _particular_ joint, without denying that there are [superexponentially](https://www.lesswrong.com/posts/82eMd5KLiJ5Z6rTrr/superexponential-conceptspace-and-simple-words) many others in the vastness of configuration space—there's something _profoundly frustrating_ about [Blue Tribe](http://slatestarcodex.com/2014/09/30/i-can-tolerate-anything-except-the-outgroup/) culture's axiomatic insistence that certain inferences _must not_ be made, that certain conceptual distinctions must not be _expressible_, except perhaps cloaked behind polysyllabic obfuscations like "assigned sex at birth" (as if the doctors made a _mistake_!).
+
+Even if many usages of words like _woman_ can and should be interpreted in a trans-inclusive sense, it's important that it also be possible to sometimes use the words in a trans-exclusive sense in those cases where the distributions of trans people and cis people of a given "gender" differ significantly for the variables of interest. The point is not to be mean to trans women (who are a huge fraction of my and _The Unit of Caring_ author's friends); the point is that it should be socially acceptable to _describe reality using words_.
+
+Consider these fictional (but, I fear, distressingly realistic) dialogues—
+
+<p class="flower-break">⁕ ⁕ ⁕</p>
+
+<div class="dialogue">
+<p><span class="dialogue-character-label">Alice</span>: I think it was <em>terribly</em> unfair how <a href="/2017/Jun/questions-such-as-wtf-is-wrong-with-you-people/">that high school track championship was won by</a> a male-to-female transgender person who wasn't even on hormone replacement therapy!</p>
+
+<p><span class="dialogue-character-label">Bob</span>: I don't see the problem. It's a girl's track meet. Trans girls <em>are</em> girls, <em>by definition</em>. Why <em>shouldn't</em> they be allowed to compete with other girls?</p>
+
+<p><span class="dialogue-character-label">Alice</span>: ...</p>
+</div>
+
+<p class="flower-break">⁕ ⁕ ⁕</p>
+
+<div class="dialogue">
+<p><span class="dialogue-character-label">Alice</span>: I'm sad that the sex ratio of my local decision-theory and compiler-development unified meetup group is so horribly lopsided, because this observation is in tension with my <a href="http://unremediatedgender.space/2017/Dec/theres-a-land-that-i-see-or-the-spirit-of-intervention/">beautiful and sacred moral ideal</a> of neither sex having a monopoly on any kind of virtue! If there's anything my native subcultures are doing to needlessly antagonize women, then that's <em>wrong</em> and I want to <em>fix it</em>!</p>
+
+<p><span class="dialogue-character-label">Bob</span>: What are you talking about? There were lots of women at that meetup.</p>
+
+<p><span class="dialogue-character-label">Alice</span>: I mean, yes, but literally all of us were trans.</p>
+
+<p><span class="dialogue-character-label">Bob</span>: So?</p>
+
+<p><span class="dialogue-character-label">Alice</span>: ...</p>
+</div>
+
+<p class="flower-break">⁕ ⁕ ⁕</p>
+
+<div class="dialogue">
+<p><span class="dialogue-character-label">Alice</span>: Have you seen <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016885">Dhejne <em>et al.</em>'s long-term followup study of transsexuals in Sweeden</a>? In Tables S1 and S2, the authors report that trans women commited violent crimes at far higher rates than cis women, with an adjusted-for-immigrant-and-psychiatric-status hazard ratio of 18.1—but only slightly lower rates than cis men, against whom the adjusted hazard ratio was 0.8.</p>
+
+<p><span class="dialogue-character-label">Bob</span>: Yes, how terrible that we still live in such a transphobic Society that those poor marginalized trans women are disproportionately driven to violent crime!</p>
+
+<p><span class="dialogue-character-label">Alice</span>: That's one theory. Can you think of any <em>other</em> possible interpretations of the data?</p>
+
+<p><span class="dialogue-character-label">Bob</span>: No.</p>
+
+<p><span class="dialogue-character-label">Alice</span>: Like, what do you make of the observation that the trans women's violent crime rate was not just higher than cis women's, but also strikingly close to that of cis <em>men</em>? Can you think of any reason—any reason at all—why that <em>might not be a coincidence</em>?</p>
+
+<p><span class="dialogue-character-label">Bob</span>: No, that has to be a coincidence. What could trans women and cis men possibly have in common?</p>
+
+<p><span class="dialogue-character-label">Alice</span>: ...</p>
+</div>
+
+<p class="flower-break">⁕ ⁕ ⁕</p>
+
+(Another dialogue about reproduction belongs in this collection, but was deemed too obvious and has been cut for space.)
+
+<p class="flower-break">⁕ ⁕ ⁕</p>
+
+The point being illustrated here is that if it's socially unacceptable for people who want to talk about sex to say "That's not what I meant by _woman_ in this context _and you know it_", then people who would prefer not to acknowledge sex will always get the last word—not because they have superior arguments, but because the terms of discourse have been [systematically engineered to conflate dissent with unkindness](/2018/Jan/dont-negotiate-with-terrorist-memeplexes/).
+
+To this it might be objected that trans activists are merely advocating for greater precision, rather than trying to make it socially unacceptable to think about biological sex: after all, you can just say "cis women" (which excludes trans women, trans men, and natal-female nonbinary people) or "assigned female at birth" (which excludes trans women, but includes trans men and natal-female nonbinary people and presumably [David Reimer](https://en.wikipedia.org/wiki/David_Reimer)) or "people with uteruses" (which excludes trans women and natal females who have had a hystorectomy) if that's what you _really mean_. I think this is underestimating the usefulness of having simple, [_short_](https://www.lesserwrong.com/posts/soQX8yXLbKy7cFvy8/entropy-and-short-codes) descriptions for the categories that do the most predictive work on typical cases.
+
+Kind or not, morally justified or not, voluntary or not, sexual dimorphism is _actually a real thing_. Studying the pages of _Gray's Anatomy_—[or _Wikipedia_](https://en.wikipedia.org/wiki/Sex_differences_in_human_physiology) if you're on a budget—you can absorb all sorts of detailed, _specific_ knowledge of the differences between female and male humans, from the obvious (sex organs, vocal pitch, height, muscle mass, body hair) to the less-obvious-but-well-known (chromosomes, hormones, pelvis shape) to the comparatively obscure (blood pressure! lymphocyte concentrations! gray-matter-to-white-matter ratios in the brain!). Nor is this surprising from a theoretical standpoint, where we have theories explaining [mechanisms by which](https://en.wikipedia.org/wiki/Sexual_selection) sexual dimorphism can evolve and [what kinds of differences](https://en.wikipedia.org/w/index.php?title=Parental_investment&oldid=832276512#Trivers'_parental_investment_theory) it produces in different species.
+
+If—like me—you're the kind of person who is not necessarily _happy_ about sexual dimorphism, you can always deliberately define your categories in order to minimize it: if there's a large sex difference in some observable measurement, just say you _don't care_ about predicting that particular measurement.
+
+But people who have _other_ concerns than minimizing Blue Tribe people's quasi-religious discomfort with sexual dimorphism (it's my former quasi-religion, too, so I'm allowed to make fun of us) might want a common word—or even just a particular _sense_ of a common word—to describe the world they see, in which sex is a real thing worth noticing. Being limited to just saying "people with uteruses" when the topic of conversation happens to be childbearing (or whatever the approved socially-just construction turns out to be) is not a suitable replacement (per Alicorn's maxim) when the speaker wants to refer to all the other dimensions along which women statistically have things in common. Including things that are hard to articulate or measure. Including things that may not even be currently _known_. _I_ certainly don't know what differences in gray-to-white brain matter ratios _mean_ psychologically, but that's a fact
+
+
+
+
+The author goes on to her second objection—
+
+> 2) Someday people are just going to be able to generate the exact physical body they want to inhabit. At that point, "biological" anything isn’t going to apply.
+
+I definitely agree that biological anything isn't going to apply in the glorious posthuman future of unimaginable power and freedom when people can reshape their body and mind at will.
+
+[(If we survive.)](https://nickbostrom.com/existential/risks.html)
+
+But it's also not clear how much relevance this science-fictional scenario has to people in the unglorious pre-posthuman present. Yes, we do have HRT and SRS, and these are magnificent acheivements for the grand cause of morphological freedom, and should be available on an informed-consent basis. It's definitely something.
+
+But it's also definitely not-everything. To get a sense of how far we have to go, I strongly recommend [Eliezer Yudkowsky's heartbreaking 2009 take on what an actually effective male-to-female sex change would take](https://www.lesswrong.com/posts/QZs4vkC7cbyjL9XA9/changing-emotions).
+
+[TODO: I used to be more optimistic]
+
+It's worth considering that when it comes to _other_ standard transhumanist goals, we typically _don't_ take the possibility of technology opening up desireable new modes of existence as thereby implying that the goals can be achieved today by means of clever redefinitions of words—
+
+<p class="flower-break">⁕ ⁕ ⁕</p>
+
+<div class="dialogue">
+<p><span class="dialogue-character-label">Alice</span>: Ever since I lost my mother, I knew I could not rest until Death itself is defeated!</p>
+
+<p><span class="dialogue-character-label">Bob</span>: But as long as you remember her, your mother lives on in you!</p>