I upvoted your comment/house because I think it can be looted for valuables, but not because I think it's sturdy enough to live in.

A lot of these so-called materialisms are actually dualisms, but they are property dualism rather than substance dualism: the mind is the brain, but it has properties like "being in a certain state of consciousness", which are distinct from, yet somehow correlated with, properties like "being made of atoms arranged in a certain way".

This is not true. The reductionist claim is that the arrangement of the atoms is entirely sufficient to produce consciousness, and not that there is consciousness and then the atoms. Until you shake this style of thought, you will never be able to see single-level-of-reality reductionism as anything more than a mutated form of dualism, which is not what it is.

But abstracted causal models are the whole of natural-scientific ontology at the present time, and materialists try to believe that that is the fundamental nature of reality,

No! Of course, if a more accurate map of reality is developed, the reductionists will say that "this is the closest we have to knowing the true base level of reality." Only strawman-level reductionists will say "this is the most accurate map we have? Okay, that's base reality." It could be that the laws of physics do fit in 500 bits, or it could be that they're just like onion layers and for whatever reason there is no bottom layer or no one ever finds it. But it is not the case that reductionism is the claim that the extent to which we have figured out how our subjectivitity is delusional, that that is The True Reality. But it's far better than just plucking from the naive intuitions. We know where they came from, after all, and it wasn't from a deep experimental study into reality.

and the aspect of reality which we experience more or less directly in subjectivity, is some sort of alien overlay.

Also not true! Why, if there was a direct one-to-one correspondence between subjective experience and reality, there would never be any surprising facts, and there would be no need to distinguish the map and the territory. In fact, I confess I have no idea what such a world would look like. What would it be like to be the universe? It is a wrong question, certainly. The subjective delusions arise from experiencing reality imperfectly, or else, once again, we would have already known about atoms and gluons and whatever-mathematics-are-really-down-there.

But I will assert emphatically that the crude reductionisms we have available to us now are radically at odds with the facts of subjective experience, and so therefore they are wrong.

And I will assert twice as emphatically that the reductionism we have available to us now, while incomplete (and knowing that it is so), is not at odds with subjective experience (they add up to normality, after all) and do more to explain the facts of subjective experience than any dualism, substance or otherwise.

You have said in the past that the computational theory of mind implies dualism. When I first saw this, I was outraged and indignant and did not wish to read any further. Later I discovered that you make much more sense than this initial impression led me to think, so I read more of your work, and yet I never found an argument that supported this claim. Do show me, if you've got one.

I will show, however, that even if the computational theory of mind is wrong (as implying dualism would necessarily force it to be), this does not matter for transhumanist realism. For even if you could not copy the brain on a computer, obviously the brain exists, so there is some way of creating them. It can and will be understood so that new brains can be made, even if its substrate isn't "computations". (I admit, though, that I have no idea what else it might be doing, that isn't computable).

Also, curse you for getting me to write in your style of incredibly long comments!

Edit: This comment was upvoted three seconds after I posted it. I don't know how or why.