Geometric Model Shows Fisher Information Resolves DNNs' Apparent Violation of Occam's Razor

FrnkNlsn · x · 2026-11-01

Frank Nielsen highlights his paper with Ke Sun, A Geometric Modeling of Occam's Razor in Deep Learning (arXiv:1905.11027, first posted 2019, revised v9 in 2025 and published in Information Geometry).

The paper tackles a puzzle: deep neural networks have enormous parameter spaces, seemingly defying Occam's razor, yet generalize remarkably well — something classical model-selection theory for regular models can't explain.

Key insight: Fisher information reveals DNNs' effective complexity is low — huge parameter counts are nearly degenerate (tangent vectors along null curves don't change the model), so high-dimensional parameter spaces don't actually violate Occam's razor, explaining DNNs' strong practical performance.

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