I think you answered this very well yourself: "In biology its not at all a good assumption that if it makes sense in your head, then it will work in a human bei

I think you answered this very well yourself: "In biology its not at all a good assumption that if it makes sense in your head, then it will work in a human being, because no single person (not even a mythical House MD) has a full mental model of what we currently understand about all our biological systems." We do our best to vet the eventual scientific feasibility of these ideas, but it's along the lines of "it makes sense in theory", not "it will definitely work". Because, as you said, our understanding of biology is so incomplete, I think that is the best that is possible right now. But I think that's ok. We (as a society) should be pursuing all the ideas that make sense. Some will work out of the box, some will work with modifications, and some just won't work at all. But this is the only way I know to make progress.