This needs to be a top-level post. Even with minimal editing. Please.

(ETA: It's not so much that we need to have another go at the cryonics debate; but the above is an argument that I can't recall seeing discussed here previously, that does substantially change the picture, and that illustrates various kinds of reasoning - about scaling properties, about predefining thresholds of acceptability, and about what we don't know we don't know - that are very relevant to LW's overall mission.)