That's true. I shouldn't have discounted the role of art so heavily.

Not art so much as philosophy. The average scientist today literally doesn't know what philosophy is. They do things like try to speak authoritatively about epistemology of science while dismissing the entire field of epistemology. Hence you get otherwise intelligent people saying things like "We just need people who are willing to look at reality", or appeals to "common sense" or any number of other absolutely ridiculous statements.

Debate seems like a dubious method of alignment because you can just indefinitely keep adjusting or introducing new auxiliary assumptions, and overarching frameworks are very rarely abandoned in this context.

Popper points out that successful hypotheses just need to be testable, they don't need to come from anywhere in particular. Scientists used to consistently be polymaths educated in philosophy and the classics. A lot of scientific hypotheses borrowed from reasoning cultivated in that context. Maybe it's that context that's been milked for all it's worth. Or maybe it's that more and more scientists are naive empiricists/inductionists and don't believe in the primacy of imagination anymore, and thus discount entirely other modes of thinking that might lead to the introduction of new testable hypotheses. There are a lot of possibilities besides the ones expounded on in OP.

I am in favor of change. I am not in favor of existence without boundaries. I don't have a moral justification for this, just an aesthetic one: a painting that contained arbitrary combinations of arbitrarily many colors might be technically sophisticated or interesting, but is unlikely to have any of the attributes that make a painting good imo. Purely subjective. I neither fault nor seek to limit those who think differently.

I was remembering an article in The Atlantic from a while ago, but I can't seem to find it now. All I can find now is this, which doesn't have the same power because it's the result of an after-the-fact search: https://www.liebertpub.com/doi/abs/10.1089/brain.2013.0172

Religion might not be, but religious thinking is, and given the general continuity of culture over time that amounts to religion being heritable in most cases. By worse than existential threat I mean Christians burning a simulated copy of you in hell for potentially k-large time; it is objectively worse than dying. Dying is just the cessation of future utility, while this would be extremely large negative utility indefinitely.

In the long run nothing looks human that follows this logic. Preserving humanity might not be utilitarian optimal, but there is something to be said for aesthetics.

Transhumanism imposes on territory that's traditionally been metaphysical or philosophical. The assumption is that it does so because of or in accompaniment with metaphysical or philosophical reasoning. Part of the reason a special disposition is assumed is because the alternative, that you don't think about what other people are thinking about at all, is probably distressing to them. This is also one of the reasons people don't like atheists. Yes, there are those who think atheists are actually all satan worshippers, but mostly they are just creeped out that atheists seem to be not thinking the kinds of thoughts that religious or spiritual people think at all. And there's plenty of neuroscience that shows the brains of atheists and religious people function differently, so it is literally a matter of being confronted with alien intelligence; a mind that cannot think in the same way; rather than merely a mind that happens to be thinking other thoughts.