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 79bbc45f41 neural: real-MNIST external-validity tier (collapse + grounding)
Confirms model collapse and its arrest by grounding on REAL images, not
just the synthetic sandbox. A conv VAE (the canonical generative-collapse
model) is retrained each generation on its own generated digits, with a
fraction g of fresh real MNIST mixed in. Modes = digit class x stroke-
thickness bin (K=30, Zipf, ~18 tail modes); the oracle is a frozen CNN +
deterministic thickness at 98.5% mode accuracy (30x30 confusion matrix
recorded in the manifest as the measurement-noise floor).

Result (4 reps): dry (g=0) collapses to a single mode -- forward-KL
0.5->18, support 30->1, tail 1.0->0.06, H->0 -- while 10% grounding holds
all 30 modes (KL~0.6, full tail, H~0.9). Signs, not magnitudes (blueprint
3.5); the exact synthetic oracle stays the quantitative anchor. The VAE
needs ~10% grounding vs the synthetic histogram's ~5%, consistent with the
grounding finding that trained nets need more than the exact operator.

Plugs into the existing data-agnostic contract (metrics/grounding/output
reused verbatim): mnist_data (thickness bins, class x thickness bijection,
MnistSampler), mnist_oracle (ClassifierOracle + confusion matrix),
mnist_vae (ConvVAEGenerator), mnist_loop (run_mnist_lineage), kind=
mnist_lineage dispatch, MnistCfg/OracleCfg. Figures: plot_mnist (parquet-
only) + mnist_montage (eyeball diagnostic showing digits degenerate to one
blurry mode). make mnist / make env-mnist, kept out of the make neural
loop. 99 tests green (+5 torchvision-gated).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-05 09:19:36 +01:00
configs neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
figures neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
paper Layer 1.5: architecture-general neural existence proof 2026-07-04 21:02:49 +01:00
results neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
src neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
tasks neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
tests neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
.gitignore neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
CLAUDE.md neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +01:00
Makefile neural: real-MNIST external-validity tier (collapse + grounding) 2026-07-05 09:19:36 +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)