NFC Architecture Decision Log#

Decision#

The main NeuroTwin architecture is now NFC: a Neural Field Compiler. The core object is a latent neural field. Pair-Operator is retained as one ablation inside this architecture, not as the project spine.

Why Old NeuroTwin Was Insufficient#

The old formulation treated windows as inputs to a predictor. That was useful for leakage-proof benchmark plumbing, but it did not separate hidden neural dynamics from modality-specific measurement physics.

Why Pair-Operator Alone Was Insufficient#

Pair-Operator tested whether low-rank region relationships improve fMRI-first forecasting. That is a real ablation, but it is not the deeper primitive. NFC keeps low-rank pair updates as one possible field interaction kernel.

Why NFC Is The New Primitive#

NFC models many sensors as partial views of one field. The model infers and evolves F_s(x,t,omega), then observation operators compile that field into fMRI, EEG, behavior, or stimulus-response outputs.

Mathematical Versus Speculative#

  • Mathematical: latent field shape, causal update, low-rank kernel, observation operators, and falsification criteria.

  • Speculative: whether the factorization improves real held-out fMRI or EEG benchmarks.

Proof Requirements#

  • Synthetic: recover latent fields and show full NFC is not equivalent to no-pair or no-observation-operator ablations.

  • Algonauts/fMRI: improve only under verified stimulus artifacts, leakage audits, and strong baseline rankings.

  • Before superiority claims: pass real held-out subject/site/dataset splits, exact or honestly labeled baseline comparisons, bootstrap intervals, and explicit scientific_claim_allowed=true in summary.json.