An Overture Famously, trans people tend not to have great introspective clarity into their own motivations for transition. Intuitively, they tend to be quite aware of what they do and don't like about inhabiting their chosen bodies and gender roles. But when it comes to explaining the origins and intensity of those preferences, they almost universally to come up short. I've even seen several smart, thoughtful trans people, such as Natalie Wynn, making statements to the effect that it's impossible to develop a satisfying theory of aberrant gender identities. (She may have been exaggerating for effect, but it was clear she'd given up on solving the puzzle herself.) I'm trans myself, but even I can admit that this lack of introspective clarity is a reason to be wary of transgenderism as a phenomenon. After all, there are two main explanations for trans people's failure to produce a good explanation for their own existence. One is that transgenderism is the result of an obscenely complex and arcane neuro-psychological phenomenon, which we have no hope of unraveling through normal introspective methods. The other is that trans people are lying about something, including to themselves. Now, a priori, both of these do seem like real possibilities. And reasonable theories have been put forward on both sides. Let's survey a couple of them now. On the "arcane neuro-psychological phenomenon" end of the spectrum, there are theories that pertain to so-called body-maps, where trans people's brains expect their bodies to have cross-sex anatomy, and feel pain when those expectations aren't met. This old, obscure blog post articulates a shallow version of this concept. I used it as an aspect of a more detailed biological theory, in my previous LessWrong post on trans issues. The body-map theory used to seem plausible to me, in large part because I have a near-constant, almost physical discomfort with my own penis. I thought that maybe, that's what drove me to transition, even th