The French Revolution abolished the système de preuve légale, replacing fixed proof-weights with jurors' intime conviction

For roughly six centuries the Roman-canon système de preuve légale — the "system of legal proofs" — fixed the probative weight of each kind of evidence in advance: a single eyewitness or a private document was a probatio semi-plena (half-proof), while only two irreproachable eyewitnesses or the accused's confession made the probatio plena (full proof) that could ground a conviction (claim-roman-canon-law-rated-one-witness-equal-to-a-private-document, claim-medieval-proof-law-graded-evidence-but-refused-to-quantify-it). The French revolutionaries dismantled this apparatus. Between 1789 and 1791 they "rejected the plausibility of a priori evidentiary rules" and replaced the fixed fractional weights with the jurors' free evaluation of the evidence — intime conviction ("inner conviction"), later codified in the Code d'instruction criminelle of 1808, whose jury instruction ends by putting to the jurors the single question "Avez-vous une intime conviction ?" (primary text: fr.wikisource.org, Code d'instruction criminelle 1808, instruction at art. 342 — this codification claim is sourced to the code itself, not to the AJLH article, which does not mention 1808).

The stated rationale was epistemic, not merely political. On the emerging probabilistic understanding, it was "impossible to prescribe a priori when sufficiently strong evidence existed": no rule fixed in advance could anticipate the infinite variety of cases, so the weighing had to be handed back to the conscience of the fact-finder in the moment. The move also expressed a distrust of the rule-bound professional magistrate — the revolutionaries trusted an ordinary juror's untethered judgment over a scale of proof written down beforehand.

This is the inverse of the half-proof machinery it replaced: where the medieval court bound the judge with legislated fractions, the revolutionary reform freed the juror from them. That inversion is what makes the vault's own graded-source ladder a structural revival run backwards — the same fixed-proof apparatus reimposed on an AI reasoner precisely because it is trusted less than the medieval court trusted its judge (observation-vault-source-tiers-revive-preuve-legale-run-in-reverse). The note fills the intime conviction lineage that claim-two-half-proofs-combined-to-full-proof-except-in-grave-criminal-cases and the half-proof taxonomy note flagged as background needing its own source.