Your entire argument seems to be "it's impossible to do this because we don't know how to do it." I don't get how people argue about the plausibility of future

Your entire argument seems to be "it's impossible to do this because we don't know how to do it." I don't get how people argue about the plausibility of future par-human AIs and say things like "we don't even know how to build a positronic brain" or "right now, in the current state of technology". It's the same kind of incomprehensible confusion that leads one to tell the Wright brothers that heavier than air flight is impossible; just as birds exist to conclusively disprove that, so do HUMANS disprove the impossibility of human-level intelligence. Maybe the three laws really are as physically illegal as a Warp Drive, though I would be remarkably surprised to hear it, but you cannot reasonably argue that position by claiming brains are impossible. None of this should be taken as an endorsement of the three laws, which are clearly silly.