Code and data associated with "The evolution of sex for artificial intelligence - A population-genetic framework for multigenerational model populations". Gilestro, 2026
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Giorgio Gilestro d22dd9d535 recombination: reproduce the E4 "merge, don't average" finding in real weights
src/neural/recombine.py mirrors Layer-1 run_coverage but trains K_T specialist RNNs on
assignments from the exact shared-switch retention construction (K_T/rho/q clean; union
matches the closed form), then recombines the measured teacher distributions two ways:
mean (naive pooling) vs oracle-guided max-merge (per-mode strongest teacher, M2N2-style),
each followed by size-n resampling.

Result (8 reps): at rho=0, union rises 0.49->0.96 (supply matches closed form); analytic
surviving_max rises 0.043->0.087 while surviving_mean stays flat ~0.045 — the conservation
law (averaging cancels the union gain, max-merge realises it). At rho=1 (identical
teachers) union and max are flat. The lesson holds in the neural setting; trained-weight
columns show the same signs but noisier (smoothing inflates baseline; deep tail barely
clears n=200 resampling). torch-gated test added. 93 tests green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-04 21:49:44 +01:00
configs recombination: reproduce the E4 "merge, don't average" finding in real weights 2026-07-04 21:49:44 +01:00
figures Layer 1 complete: E3-E6 + E2 analysis add-ons 2026-07-04 18:54:42 +02:00
paper Layer 1.5: architecture-general neural existence proof 2026-07-04 21:02:49 +01:00
results recombination: reproduce the E4 "merge, don't average" finding in real weights 2026-07-04 21:49:44 +01:00
src recombination: reproduce the E4 "merge, don't average" finding in real weights 2026-07-04 21:49:44 +01:00
tasks recombination: reproduce the E4 "merge, don't average" finding in real weights 2026-07-04 21:49:44 +01:00
tests recombination: reproduce the E4 "merge, don't average" finding in real weights 2026-07-04 21:49:44 +01:00
.gitignore Layer 1.5: architecture-general neural existence proof 2026-07-04 21:02:49 +01:00
CLAUDE.md recombination: reproduce the E4 "merge, don't average" finding in real weights 2026-07-04 21:49:44 +01:00
Makefile Layer 1.5: architecture-general neural existence proof 2026-07-04 21:02:49 +01:00
pyproject.toml Layer 1.5: architecture-general neural existence proof 2026-07-04 21:02:49 +01:00
README.md Layer 1 core: Wright-Fisher knowledge-transmission model with E1-E2 2026-07-04 18:10:18 +02:00
uv.lock Layer 1.5: architecture-general neural existence proof 2026-07-04 21:02:49 +01:00

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 WrightFisher 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) and paper/the-lamarckian-society-v4.md (the perspective paper).

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 E1E6
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)