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> Epistemics > Confidence and Calibration > arghXiv:2608.02701

A Note on the Standard of Evidence Appropriate to Extraordinary Claims

Lionel Trask

Abstract: It is widely accepted that an extraordinary claim requires evidence in proportion to it. The principle is sound and is applied, in practice, in one direction only. This note argues that a claim's extraordinariness is a function of what a given party already accepts, that no procedure has been proposed for establishing it independently, and that in the absence of such a procedure the principle licenses any standard whatever, applied to any claim, by any party. Nothing here should be read as scepticism about any particular result. The argument is entirely about the standard, and would hold if every claim to which it has been applied were true.

Comments:
31 pages. Expanded from a note of four pages circulated in 2025.
Subjects:
Confidence and Calibration (epist.CONF) (primary class); Verification and Provenance (epist.VER); Moves and Tactics (argu.MOV); Sourcing (epist.SRC)
TDC classes:
0.01; 8.12
Cite as:
arghXiv:2608.02701v1 (BibTeX)
Submission history:
From: Lionel Trask [view email]
[v1] Thu, 13 Aug 2026