Hand-crafted 16-neuron net matches trained model (96.0% vs 95.3%), Hilton proposes faithfulness metrics

JacobHHilton · x · 2026-10-18

A community reverse-engineering project drew in Jacob Hilton (ex-OpenAI superalignment). DragggonZ claims to have identified each neuron's role in a 16-neuron network and rebuilt it by hand with Claude's help, no training needed: 96.0% accuracy vs 95.3% for the ARC-trained original, with weight maps relabelled and rescaled to show the same function. Hilton suggests quantitatively measuring mechanistic faithfulness: propagate a probabilistic hidden-state model using each neuron's identified function to produce a mechanistic estimate of the original's accuracy, treating ideal-vs-actual weight discrepancies as noise — and even mechanistically predicting accuracy degradation under added weight noise like N(0, 0.0025²), which typically costs 1-10 accuracy points.

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