LeCun weighs in on bioplausible learning debate: "everything works on MNIST"

aran_nayebi · x · 2026-09-16

Sakana AI's bioplausible learning work drew in Yann LeCun, who noted it is essentially a version of "target prop": each layer's input acts as a free latent variable serving as a target for the previous layer, derivable from an augmented Lagrangian formulation of backprop where layer-consistency constraints become penalty terms.

Researcher Aran Nayebi pushed back: these results are only on MNIST, where even trivial methods like Feedback Alignment work — "everything works on MNIST." The real test for a bioplausible algorithm is whether it learns at scale without weight transport; he points to work from six years ago showing bioplausible learning scaling with backprop on ImageNet, and links the relevant paper.

Related event: Sakana AI Unveils PC-ALM: Training 1000-Layer Nets Without Backprop(5 posts)→

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