Code and data associated with "The evolution of sex for artificial intelligence - A population-genetic framework for multigenerational model populations". Gilestro, 2026
Giorgio Gilestro
6b5591c92f
The five priority fixes, in the PNAS draft and propagated to the
long-form document and results documentation:
1. The averaging proposition now proves what it claims: a FIRST-ORDER
cancellation of the multi-parent retention gain under output-mean
inheritance in the rare-item regime (n·p/K << 1), with the convexity
boundary stated (averaging's variance reduction can reduce extinction
outside that regime — the reviewer's argument) and the union
operator's renormalisation + oracle requirement explicit. "Adding
parents cannot help" deleted everywhere.
2. Grounding: g*~=0.05 restated as an operational threshold (equilibrium
smooth in g — no phase transition); m·p floor restated as
1−exp(−m·p) per-batch observation probability with
retention/occupancy/reintroduction distinguished; the deep-tail rule
de-categoricalised (stratified sampling; recombination recovers only
what parents retain).
3. Grounded INHERITANCE (data channel) separated from grounded
EVALUATION (fitness channel) in the society section; retitled to
"complementary contributions"; general joint necessity disclaimed.
Table 1 + v6 ledger updated.
4. Alignment contradiction removed everywhere ("cannot be an alignment
failure" -> the reviewer's formulation); abstract says "remaining
after permutation-and-rescaling alignment"; group = search space,
control recovery != global optimality; "specialisation is merge-safe"
-> "do not treat divergence/specialisation alone as evidence of
incompatibility".
5. Significance headline matched to the bounded evidence; seed-
dependence sensitivity added (per-seed rho stable +0.37..+0.53 for
functional measures, ~0 for geometry, gradient alignment
seed-UNSTABLE −0.11..−0.55 — reported as its own caveat; LOSO ranges
in stats script).
Presentation: review-process meta-language stripped; "exact" reserved
for closed forms ("analytic model" labels); headroom rule qualitative;
directed-sex phrasing per review; ratchet = consequence-level
correspondence; compact results table (Table 2) added. Response letter:
paper/response-to-review-3.md. Both PDFs rebuilt; 151 tests green.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BkRLcc18rwT2Lysu6PbG7v
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| hpc | ||
| paper | ||
| results | ||
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| .gitignore | ||
| CLAUDE.md | ||
| Makefile | ||
| pyproject.toml | ||
| README.md | ||
| uv.lock | ||
The Lamarckian Society — Layer 1 (analytical core)
A parametric population-genetics model of knowledge transmission across generations of
learning agents. Knowledge transmission is modelled literally as a Wright–Fisher
process (not by analogy): a model's knowledge is a distribution p_t over K discrete
items; a fixed true distribution p* has a rare tail; each generational step is
"sample from the parent (drift) + mix in fresh real samples (grounding/immigration) +
refit." Model collapse is the loss of rare alleles under drift.
See paper/blueprint.md (the normative build spec),
paper/the-lamarckian-society-v5.md (the perspective paper), and
paper/results-summary.md (a summary of all results).
Reproduce
Environment is a uv venv built from the committed, hash-pinned uv.lock — that
lockfile is the single source of truth for "it runs" (Layer 1 is pure NumPy/SciPy and
bitwise-reproducible from a seed; no container needed).
# one-time: install uv (https://astral.sh/uv)
curl -LsSf https://astral.sh/uv/install.sh | sh
uv sync # build .venv from uv.lock
make test # correctness + scientific-validation tests (the spine of trust)
make layer1 # run experiments E1–E6
make figures # regenerate figures from committed results
Layout
src/knowledge/ Layer 1 package (imported as `knowledge`)
configs/layer1/ one YAML per experiment (E1..E6)
figures/ plot_EX.py — read results.parquet only
tests/ test_correctness.py + test_scientific_validation.py (analytic checks)
paper/ blueprint.md, perspective paper, figure_manifest.md
results/ written artifacts (gitignored; hashes tracked in manifest.json)