Agreed, and you’ll note that I haven’t argued that you owe anyone anything. I don’t think people have a property right in being recognized as the sex of their choice, and I’ve explicitly rejected any legal obligation to do so.
But I think doing so is part of the ‘civility’ that you describe, and I also think that in many cases the world is best described by doing so. On to that:
First, ‘bad driving’ seems a bit of a loaded example of social sexual roles, and not one I’m defending. I don’t think transwomen are identifying as women because they drive poorly. More central examples would point to more central social role dichotomies, e.g. hunter vs. gatherer, defender vs nurturer, competition vs. cooperation, hard vs. soft, strength vs. caring, violence vs. persuasion, brawn vs. beauty, etc. Even in a far future where sex becomes meaningless in the way you suggest later in your post, these dichotomies might well persist, because they reflect different game-theoretic social strategies that it may continue to make sense for people to specialize in, and which may continue to be correlated. (This is a new claim, and one I would also be interested to hear Karpel Tunnel’s thoughts on).
But to your larger point about getting it wrong and solving that mistake, if I might draw a parallel (and I apologize if you know the story): Until the mid 1800s, jade was believed to be a single mineral. In 1863, it was discovered that it was two distinct minerals, jadeite and nephrite, with different composition and different properties that were capable of distinguishing them, once people knew to look. Following the discovery that what we believed was one thing was actually two things, we had three options: 1) say that only jadeite is real jade, 2) say that only nephrite is real jade, or 3) say that both continue to be real jade.
We can look at what’s going on here in a similar way: there was something we called ‘man’ thought of as one thing. Then we revised our ontology to distinguish between man the biological sex category and man the social role category. We are then presented with three options, and I think you can see where I’m going here: 1) say that only the biological thing is a real man, 2) say that only one who occupies the social role is a real man, or 3) say that both continue to be real men.
We can debate which is the best option, but it is wrong to say that there is only one solution.
I’m not sure that that’s it, but this feels like progress. I don’t think I’ve said that subjective perception is sufficient, and if I have I was wrong. Rather, where subjective perception is clearly communicated by adherence to norms for the perceived sex and communicates an accurate picture how how a person wants to be treated and can be expected to behave, that is sufficient, because one sense of sex is the norms and the expectations about behavior and treatment they are intended to inform.
The role of subjectivity here is in 1) people being the local experts on themselves, so that they are the best qualified to testify as to what we should expect from them and how they wish to be treated, and 2) making their communication sincere.
I think this is a fair point, and you’re right that we shouldn’t pretend the technology exists in deciding how to treat people now. I bring it up now only to tease out the ontology of sex.
But I do worry that there was likely a time when people would have said that it was genital shape and hormones that made the man, and then plastic surgery and hormone therapy advanced to the point they are now and the goalposts were moved. I don’t mean to accuse you of doing this, you’ve been consistent throughout this conversation and I have every reason to believe you will remain consistent as technology advances. But I think we can probably agree that the conversation will move with what’s possible, so that the magic plank in Theseus’ ship can never be replaced.