-It would be hard to overstate how much of an impact this post had on me. I've previously linked it on this blog eight times. In June 2008, half a year before it was published, I encountered the [2004 mailing list post](http://lists.extropy.org/pipermail/extropy-chat/2004-September/008924.html) that was its predecessor. (The fact that I was trawling through old mailing list archives searching for Yudkowsky content that I hadn't already read, tells you something about what a fanboy I am.) I immediately wrote to a friend: "[...] I cannot adequately talk about my feelings. Am I shocked, liberated, relieved, scared, angry, amused?"
+But, well ... I mean, um ...
+
+(I still really don't want to be blogging about this, but _somebody has to and no one else will_)
+
+From the standpoint of my secret erotic fantasy, "normal, masculine man wearing a female body like a suit of clothing" is actually a _great_ outcome—the _ideal_ outcome. Let me explain.
+
+The main plot of my secret erotic fantasy accomodates many frame stories, but I tend to prefer those that invoke the [literary genre of science](https://www.lesswrong.com/posts/4Bwr6s9dofvqPWakn/science-as-attire), and posit technology indistinguishable from magic rather than magic _simpliciter_.
+
+So imagine having something like the transporter in _Star Trek_, but you re-materialize with the body of someone else, rather than your original body—a little booth I could walk in, dissolve in a tingly glowy special effect for a few seconds, and walk out looking like (say) [Nana Visitor (circa 1998)](https://memory-alpha.fandom.com/wiki/Kay_Eaton?file=Kay_Eaton.jpg). (In the folklore of [female-transformation erotica](/2016/Oct/exactly-what-it-says-on-the-tin/), this machine is often called the ["morphic adaptation unit"](https://www.cyoc.net/interactives/chapter_115321.html).)
+
+This high-level description of a hypothetical fantasy technology leaves some details unspecified—not just the _how_, but the _what_. What would the indistinguishable-from-magical transformation booth do to my brain? [As a preference-revealing thought experiment](https://www.lesswrong.com/posts/DdEKcS6JcW7ordZqQ/not-taking-over-the-world), what would I _want_ it to do, if I can't change [the basic nature of reality](https://www.lesswrong.com/posts/tPqQdLCuxanjhoaNs/reductionism), but if engineering practicalities weren't a constraint? (That is, I'm allowed to posit any atom-configuration without having to worry about how you would get all the atoms in the right place, but I'm not allowed to posit tethering my immortal soul to a new body, because [souls](https://www.lesswrong.com/posts/u6JzcFtPGiznFgDxP/excluding-the-supernatural) [aren't](https://www.lesswrong.com/posts/7Au7kvRAPREm3ADcK/psychic-powers) [real](https://www.lesswrong.com/posts/fdEWWr8St59bXLbQr/zombies-zombies).)
+
+The anti-plug-and-play argument makes me confident that it would have to change _something_ about my mind in order to integrate it with a new female body—if nothing else, my unmodified brain doesn't physically _fit_ inside Nana Visitor's skull. ([One meta-analysis puts the sex difference in intracranial volume and brain volume at](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969295/) a gaping [Cohen's _d_](/2019/Sep/does-general-intelligence-deflate-standardized-effect-sizes-of-cognitive-sex-differences/) ≈ 3.0 and 2.1, respectively, and Visitor doesn't look like she has an unusually large head.)
+
+Fine—we're assuming that difficulty away and stipulating that the magical transformation booth can make the _minimal_ changes necessary to put my brain in a female body, and have it fit, and have all the motor-connection/body-mapping stuff line up so that I can move and talk normally in a body that feels like mine.
+
+I want this more than I can say. But is that _all_ I want? What about all the _other_ sex differences in the brain? Male brains are more lateralized—doing [relatively more communication within hemispheres rather than between](https://www.pnas.org/content/111/2/823); there are language tasks that women and men perform equally well on, but [men's brains use only the _left_ inferior frontal gyrus, whereas women's use both](/papers/shaywitz-et_al-sex_differences_in_the_functional_organization_of_the_brain_for_language.pdf). Women have a relatively thicker corpus callosum; men have a relatively larger amygdala. Fetal testosterone levels [increase the amount of gray matter in posterior lateral orbitofrontal cortex, but decrease the gray matter in Wernicke's area](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306238/) ...
+
+Do I want the magical transformation technology to fix all that, too?
+
+Do I have _any idea_ what it would even _mean_ to fix all that, without spending multiple lifetimes studying neuroscience?
+
+I think I have just enough language to _start_ to talk about what it would mean. What makes it hard to think about is that humans don't really _know_ how our own minds work. Evolution endowed us with certain capacities for making sense of the world, in our own way, when making sense of the world increased fitness in the environment of evolutionary adaptedness, but this mostly doesn't extend to making sense of the _mechanisms by which_ we can make sense of the world.