> You're using absence of evidence as evidence of absence — which is a weak foundation when the evidence is genuinely hard to capture. You can't ethically deprive humans of sleep to death in a lab, and FFI affects only a handful of families worldwide.

> On the prion disease specifically: researchers haven't dismissed the role of sleep deprivation they've actively attempted to treat the insomnia in FFI patients on the hypothesis that it contributes to decline. That's not how a field behaves when it considers something a settled, irrelevant symptom.

> More broadly, "no human has ever died from lack of sleep" is an extraordinarily strong claim. To support it you'd need to rule out sleep deprivation as a factor in every candidate case and have a complete understanding of the mechanism. We have neither. The honest position is "we don't know" — not confident assertion in either direction.