---
conjecture: r3-b1-03
family: codex
model: "gpt-5.6-sol (codex-cli 0.144.0-alpha.4, ChatGPT-subscription auth)"
model_stamp_corrected: "2026-08-07 — archives were first written stamped gpt-5.5 by a runner bug (the stamper read config.toml's default instead of the -m flag actually passed). The calls themselves ran on gpt-5.6-sol throughout; only the label was wrong. Corrected in place, noted here rather than silently."
received: 2026-08-07
template: PROMPT_TEMPLATE_v1.md sha256 4344aabfacfe88362c56d89b6c89d594a7bf3a221e18a16b0e351482447e512f
rivals_parsed: 3
validation: VALID
---

{
  "rivals": [
    {
      "mechanism": "The apparent chronological difference is generated by source-specific dateability and cataloguing selection rather than by different fragment-generating processes. Genizah fragments receiving dates may be disproportionately late, legible, or otherwise classifiable items, while its earlier or less legible material remains among the 90.1% undated.",
      "why_it_explains_the_same_evidence": "The extreme difference in dated coverage, 9.9% for the Genizah subset versus roughly 75% and 97% for the European sources, permits strong informative-missingness bias. If dateability increases for later Genizah material, the mean among catalogued dates can be about 190 years later even when the underlying fragment populations are not; the same pattern would persist in future additions produced under the same cataloguing workflow. There is no held-out outcome imposing an additional constraint.",
      "named_confounds": [
        "informative missingness of dates",
        "source-specific cataloguing thresholds",
        "legibility and dateability selection",
        "unequal dated-item denominators"
      ],
      "discriminating_test": {
        "description": "Draw source-stratified random samples from the currently undated fragments, have them dated blindly using one common protocol, and recompute means including those estimates. Also model the probability of receiving a catalogue date from metadata available for every fragment. The rival predicts that newly dated Genizah items will be substantially earlier than the currently dated Genizah subset and that coverage-adjusted means will narrow the approximately 190-year gap; the proposed population-process mechanism predicts a substantial residual gap under harmonized dating.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "A markedly earlier mean for randomly selected previously undated Genizah fragments, with the standardized or expanded Genizah mean approaching the European means."
      }
    },
    {
      "mechanism": "The European means may be size-weighted products of a small number of parent manuscripts that generated many separately catalogued leaves, rather than estimates from thousands of independent historical objects. Similar record-splitting or reconstruction practices across the two European catalogues could make both means converge near 1280.",
      "why_it_explains_the_same_evidence": "A few highly fragmented codices dated near 1280 can dominate a fragment-weighted mean when every leaf is counted separately, whereas different bundling or parent-object reconstruction in the Genizah catalogue produces a differently weighted mean. Continued cataloguing under the same record-creation rules could reproduce the pattern without any intrinsic chronological difference between binding-waste and deposit processes. Again, no held-out result must additionally be explained.",
      "named_confounds": [
        "non-independence of fragments from the same parent manuscript",
        "record-splitting and bundling differences",
        "size-biased weighting by surviving leaf count",
        "catalogue-level pseudoreplication"
      ],
      "discriminating_test": {
        "description": "Link fragments to reconstructed parent manuscripts, shared shelfmarks, or the narrowest available provenance clusters, then compare the registered fragment-weighted means with means assigning equal weight to each parent or cluster and bootstrap at that level. The rival predicts that parent-weighting will materially move at least one European mean, weaken their convergence, or substantially reduce the European-Genizah difference; the proposed mechanism predicts that the chronological separation remains robust.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "The near-1280 convergence or the approximately 190-year gap disappears or becomes much smaller after equal weighting of parent manuscripts or provenance clusters."
      }
    },
    {
      "mechanism": "The difference may reflect the historical composition of the catalogues—especially region, language, script, genre, and institutional collecting remit—rather than the process that turned manuscripts into loose fragments. The two European collections could converge because both disproportionately sample the same medieval European book-production strata, while the Genizah subset samples later documentary or textual strata.",
      "why_it_explains_the_same_evidence": "Shared European production and collecting profiles can independently generate similar means even across separately curated collections, while a compositionally different Genizah catalogue produces a later mean. Future records drawn from the same remits would preserve the contrast, so replication by source alone would not distinguish this mechanism from a disposal-versus-deposit mechanism. The absence of a held-out test leaves this compositional alternative unresolved.",
      "named_confounds": [
        "geographic composition",
        "language and script composition",
        "text-genre composition",
        "institutional collecting-remit selection",
        "differential digitization or cataloguing by content type"
      ],
      "discriminating_test": {
        "description": "Using fragment-level metadata, define strata for region, language or script, textual genre, and document-versus-book status; restrict to strata represented in both source families and standardize all sources to one common stratum distribution. The rival predicts that within-stratum source differences and the standardized date gap will be small, whereas the proposed fragment-generation mechanism predicts a persistent binding-waste versus Genizah difference after composition is held constant.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "The source contrast largely vanishes within overlapping strata or after common-distribution standardization, with most of the raw gap attributable to differing stratum proportions."
      }
    }
  ],
  "no_viable_rival": false,
  "notes": "No held-out test has been run, so these rivals are assessed solely against the training pattern; persistence under unchanged cataloguing practices would not by itself distinguish them."
}
