---
conjecture: r3-b1-03
family: grok
model: "Grok 4.5 expert (chat paste-back via orchestrator window)"
received: 2026-08-06
template: PROMPT_TEMPLATE_v1.md sha256 4344aabfacfe88362c56d89b6c89d594a7bf3a221e18a16b0e351482447e512f
rivals_parsed: 2
---

{
  "rivals": [
    {
      "mechanism": "The observed mean-date gap is an artifact of differential dating completeness and selection: the binding-waste sources date a high fraction of their fragments using conventions that favor assigning mid-medieval European paleographic dates, while the Genizah subset's much lower dated rate (9.9%) preferentially retains later, more securely datable items, shifting its mean later without any difference in underlying fragment-generation processes.",
      "why_it_explains_the_same_evidence": "If cataloguers in the binding-waste collections systematically date nearly all fragments into the 1150-1450 window while Genizah cataloguers leave most undated and date only a later-biased subset, the training means (both binding ~1280, Genizah ~1472) and the convergence of the two independent binding sources would appear identically, even if the physical populations were chronologically similar.",
      "named_confounds": ["cataloguing practice for date assignment", "selection effects in which fragments receive precise dates", "differential dated-fraction bias"],
      "discriminating_test": {
        "description": "Compute the mean cataloged date for the undated (or low-precision) remainder in each source after applying any available secondary dating proxies (e.g., script style frequencies or known parallel dated exemplars), or restrict the comparison to only the highest-precision dated subset of equal relative size across sources; measure whether the mean gap closes or persists.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "If the mean gap disappears or reverses once dated fractions are equalized or secondary proxies are included, this favors the rival (dating-selection artifact); if the ~190-year gap remains under equalized dating, this favors the proposed distinct-population mechanism."
      }
    },
    {
      "mechanism": "The two binding-waste collections and the Genizah subset simply sample different geographic and cultural production centers whose peak parchment-use periods happened to differ by ~190 years, without any special distinction between 'binding-waste reuse' versus 'deposit-trove' generation processes.",
      "why_it_explains_the_same_evidence": "European binding-waste sources would then converge on a mid-medieval mean because that is when European parchment production and reuse peaked, while Genizah (primarily Mediterranean/Near-Eastern) material would show a later mean reflecting that region's different chronological profile; the training numbers would match exactly and future growth of the same sources would preserve the gap.",
      "named_confounds": ["geographic/cultural production chronology differences", "selection effects in which regions' fragments enter each catalogue"],
      "discriminating_test": {
        "description": "Stratify each source's dated fragments by script language, known place of origin, or paleographic region and recompute mean dates within matching strata (e.g., only Latin European vs only Judeo-Arabic); measure whether the overall mean gap collapses inside strata or persists across them.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "If within-stratum means become statistically indistinguishable while the overall gap is driven by differing regional composition, this favors the rival; if the gap remains large even inside matched regional strata, this favors the proposed process-difference mechanism."
      }
    }
  ],
  "no_viable_rival": false,
  "notes": ""
}
