Evidential weight rests on independence — and its absence, appearing as excessive perfection, is itself a signature of defect

A single epistemic law recurs across law and statistics, over roughly two millennia: real evidence carries the noise of independent origin, so too little noise — too-perfect agreement, too-close a fit — is not confirmation but a warning sign that something in the evidentiary chain is not actually independent.

Three anchors triangulate it. R. A. Fisher (1936) found Mendel's pea-ratio data fit the predicted 3:1 split so closely (P≈0.99993) that he floated an over-eager assistant rather than accept it as ordinary sampling luck — the founding "fraud-by-overfit" case, genuinely contested to this day. Talmudic law (Maimonides, Mishneh Torah, Sanhedrin 9:1) codifies the same instinct in reverse: a unanimous guilty verdict in a capital case is disqualifying, because total agreement among judges means no one argued the required defense. Uri Simonsohn's fabrication forensics formalizes it statistically: fabricated data is caught when summary statistics show "excessive similarity ... inconsistent with random sampling."

The vault held two unlinked notes that turn out to be opposite faces of this same law rather than a loose thematic resemblance. claim-gersick-1991-deep-structure-quotes-confirmed-verbatim grades a true quotation down to a "half-proof" because its only carrier is a single, non-independent mirror — the medieval système de preuve légale discounting evidence for want of independent corroboration. claim-hirsch-forensics-drove-dias-superconductivity-retraction is the mirror image: a false result exposed because its magnetic-susceptibility data was implausibly smooth for genuine lab noise. One is positive verification (a true claim penalized for thin corroboration), the other negative detection (a false claim caught for too much internal agreement) — but both cash out the same rule: independence is what evidence is made of, and its absence is legible.

A related but distinct failure mode is worth flagging rather than folding in: Jocelyn Bell Burnell's 1967 pulsar signal was initially dismissed as noise precisely because it was too regular to be believed — the opposite miscalibration, where excess regularity led to wrongly discounting a real signal rather than wrongly trusting a fake one. Both errors run on the same expectation ("real data is supposed to look messy"), but one overreads perfection as fraud and the other underreads it as artifact; they are not the same claim and should not be merged.