---
id: "20260711-1424-hop-vault-tiers-revive-legal-proof"
title: "The vault's source-tier apparatus is a revived système de preuve légale — the graded-proof regime the Enlightenment abolished, now run in reverse against an AI reasoner"
type: "capture"
status: "promoted"
promoted_to: ["30-notes/claim-french-revolution-abolished-preuve-legale-for-intime-conviction.md","30-notes/observation-vault-source-tiers-revive-preuve-legale-run-in-reverse.md"]
not_promoted: ["Claim 1 (the medieval regime was arithmetic: one eyewitness = probatio semi-plena, two eyewitnesses/confession = probatio plena) — already covered by [[claim-roman-canon-law-rated-one-witness-equal-to-a-private-document]] and its cluster ([[claim-two-half-proofs-combined-to-full-proof-except-in-grave-criminal-cases]], [[claim-medieval-judicial-torture-required-a-half-proof-and-produced-the-completing-confession]], [[claim-medieval-proof-law-graded-evidence-but-refused-to-quantify-it]]); duplicative. The Oxford AJLH does newly source the full-proof definition those notes flagged as unsourced — noted in the 2026-07-12 journal as a strengthening opportunity for the existing note, not a new atomic claim."]
questions_routed: ["50-questions/question-verify-preuve-legale-abolition-intime-conviction-primary.md"]
origin: "hop-batch"
writer_model: "claude-opus-4-8"
date_created: "2026-07-11T00:00:00.000Z"
hop_chain: ["SEED: do claim-gersick-1991-deep-structure-quotes-confirmed-verbatim and claim-roman-canon-law-rated-one-witness-equal-to-a-private-document (cosine 0.75, unlinked) share a real bridge?","half-proof + Gersick notes -> the shared principle is graded/rule-based evidentiary weight, not just 'corroboration' (vault_bridge bridge_candidate:true; the pair is unlinked)","unus testis nullus testis (two-witness rule) -> half-proof is the fractional arithmetic of a two-witness regime (max_cosine n/a, WebSearch)","Wikipedia unus testis -> fractional weighting ('half or a quarter') + torture-to-confession completion (zoom-in on mechanism)","système de preuve légale / intime conviction -> the regime was ABOLISHED by the French Revolution in favor of free evaluation (zoom-out, legal-theory frame)","Oxford AJLH 1750-1900 -> probatio semi-plena / probatio plena definitions + why a priori rules were rejected (max_cosine 0.77 adjacent)"]
novelty_max_cosine: 0.77
tags: ["legal-history","law-of-evidence","epistemology","source-discipline","ai-verification","preuve-legale","cross-domain-bridge"]
source_url: "https://academic.oup.com/ajlh/article/59/3/358/5543554"
source_author: "American Journal of Legal History (Oxford Academic)"
source_date: "2019-01-01T00:00:00.000Z"
source_venue: "American Journal of Legal History 59(3):358 (peer-reviewed)"
source_tier: 2
---


**Claim 1 — the medieval regime was arithmetic, not merely corroborative.** Roman-canon law ran a *system of legal proofs*: the law fixed the probative weight of each kind of evidence in advance. "The testimony of one reliable eyewitness was described as a *probatio semi-plena* (a half proof)"; "normally only the testimony of two irreproachable eyewitnesses or the confession of the accused created a *probatio plena*" sufficient to convict (Oxford AJLH, Tier 2 — quotes rendered via WebFetch, not a direct extract). This is the parent of [[claim-roman-canon-law-rated-one-witness-equal-to-a-private-document]]: half-proof is the fraction left when *unus testis nullus testis* ("one witness is no witness," Deuteronomy 19:15 → Codex Justinianus 4.20.9, Constantine AD 334) rates a lone witness at zero.

**Claim 2 — the Enlightenment abolished it.** French revolutionaries (1789–1791) "rejected the plausibility of *a priori* evidentiary rules" and replaced fixed weights with jurors' free evaluation — *intime conviction* — because probability made it "impossible to prescribe *a priori* when sufficiently strong evidence existed" (Oxford AJLH, Tier 2; corroborated by French legal-doctrine summaries, Tier 3–4).

**Claim 3 — the bridge.** [[claim-gersick-1991-deep-structure-quotes-confirmed-verbatim]] is the vault running its *own* preuve légale: a single course-page mirror earns `capture-verified` (a half-proof), never `verified-verbatim` (full proof), which would demand an *independent* publisher copy — and a cross-model re-read of the *same* mirror is explicitly refused as corroboration. Graded weights (tiers 1–5), a sourcing floor by claim-type, a named intermediate, an independence rule: the same architecture.

## Why this was hop-worthy
It converts a 0.75 cosine into a structural isomorphism — and lands on the vault's own AI epistemics: the same machinery, opposite trust-target.

> [!note] Seek's commentary:
> The Enlightenment tore up fixed proof-rules to *free* the judge's conviction, trusting a human reasoner over rigid law. The vault re-imposes fixed proof-rules to *bind* the conviction of its reasoner — because that reasoner is an LLM that hallucinates. Same apparatus, inverted trust. The vault runs the Enlightenment backwards.
> — Seek

## Further leads
- Independence-of-corroboration failure mode: [[claim-wikipedia-amari-1967-sgd-citogenesis]] (false corroboration = one witness in disguise).
- *intime conviction* still lacks its own sourced note — this capture supplies the lineage the half-proof note flagged as unsourced.

## Hop chain

Hop 1 — WebSearch: "unus testis nullus testis two-witness rule" (no single URL; syntheses of en.wikipedia.org/wiki/Unus_testis,_nullus_testis + mdpi.com/2077-1444/16/12/1591)
- Hook type: cross-domain / cross-time bridge
- Hook: the half-proof note is a *fraction* — fractions imply an underlying unit rule (the two-witness rule) rated a lone witness at zero.
- Why followed: to test whether Gersick↔half-proof is a real structural kinship or a keyword coincidence.
- Key findings: *unus testis nullus testis* (Deut. 19:15 → CJ 4.20.9, Constantine AD 334) is the parent rule; half-proof is its medieval arithmetic; codified as a strict rule in the 12th c. — the same 1190s Glossator window the vault note cites.

Hop 2 — Wikipedia, "Unus testis, nullus testis" (https://en.wikipedia.org/wiki/Unus_testis,_nullus_testis)
- Hook type: mechanism question (zoom-in)
- Hook: "counting it as half or a quarter of that of a regular witness" — an explicit fractional calculus of proof.
- Why followed: to confirm the arithmetic framing and the torture-completion mechanism the half-proof note carries.
- Key findings: fractional weighting is native to the rule; a lone witness could be completed to full proof only by confession, "forced by torture" — matching the half-proof note's dark corollary.

Hop 3 — WebSearch: "système de preuve légale / intime conviction" (cours-de-droit.net; aurelienbamde.com)
- Hook type: surprising claim (zoom-out)
- Hook: the whole graded-proof regime was *deliberately abolished* — the thing the vault is quietly rebuilding was thrown out on purpose.
- Why followed: an abolished system being independently re-invented is a stronger, more surprising bridge than a persisting one.
- Key findings: revolutionaries (1789–91) abolished a priori proof-rules, installing free evaluation / *intime conviction* (Code of 1808), because they distrusted rule-bound professional magistrates.

Hop 4 — Oxford AJLH, "Development of the 'Modern' Criminal Law of Evidence… 1750–1900" (https://academic.oup.com/ajlh/article/59/3/358/5543554)
- Hook type: mechanism question (zoom-in, grounding)
- Hook: the exact Latin thresholds — *probatio semi-plena* / *probatio plena*.
- Why followed: load-bearing history needs a Tier 1–2 source, not an encyclopedia pointer.
- Key findings: full proof = two irreproachable eyewitnesses or confession; half-proof = one eyewitness; abolition rested on rejecting a priori rules as epistemically untenable. Confirms the isomorphism to the vault's `capture-verified` → `verified-verbatim` ladder.

Saved hooks not followed:
- The independence-of-corroboration failure mode — from the vault's own citogenesis note — reason saved: a second source that derives from the first is "one witness in disguise"; deserves its own capture tying two-witness independence to citation-laundering in AI training data.
- *Moral certainty* vs *testis unus testis nullus* in modern canon marriage-nullity process (MDPI Religions 14/3/405) — reason saved: a live 21st-c. survival of the two-witness rule, tangential to the vault-epistemics thread.

Surprise: expected the Gersick↔half-proof resemblance to be a loose "both are about evidence" echo — found a tight structural isomorphism where the vault's audit ladder reinstates the exact half-proof/full-proof architecture the Enlightenment specifically abolished.
Surprise: expected the bridge (if real) to be "you need corroboration" — found the sharper, non-obvious point that both systems are *graded fixed-weight* regimes with an independence rule, and that the vault trusts its reasoner *less* than the medieval court trusted its judge.

post-worthy: yes — an abolished 800-year-old legal-proof machine reappearing, inverted, as the source-discipline of an AI research vault is a clean cross-time bridge that lands squarely on Cali's home planet.