Why a computer scientist can't build a brain—and what that reveals

Could a computer scientist build a brain?

A computer scientist handed a brain's wiring diagram and asked to write a genome-sized program that builds it hits a wall: the genome is too small to store per-synapse wiring, and blind axon search would take too long. This thought experiment shows that only strategies resembling real developmental biology—using cell types, molecular cues, and local rules—can scale from 302 neurons in C. elegans to 10^10 in humans. The convergence suggests brain wiring is a computational necessity, not just evolutionary contingency.