A fundamental constraint governing coherent transport is identified and formalized. Contrary to the prevailing assumption that stronger interaction enhances coordination, this work demonstrates that stable transport emerges only when coupling exceeds a minimal, nonzero threshold—and that systems universally select the lowest coupling that preserves continuity.Across nonlinear, saturation-driven networks, a sharply defined lower bound on coupling strength is observed. This threshold remains invariant under changes in suppression, scoring conditions, and environmental parameters, while the admissible range of stronger coupling is dynamically constrained. Systems do not optimize by increasing interaction, but by minimizing it subject to a viability condition.The result is a general law: coherent transport is achieved not through maximal connectivity, but through minimal stable coupling. This principle provides a unified explanation for sparse signaling in neural systems, weak interaction regimes in cytoskeletal transport, and stability limits in distributed networks.The law is falsifiable and produces direct experimental predictions, including invariance of activation thresholds under varying suppression and the collapse of stability under excessive coupling. It reframes transport, coordination, and propagation as constraint-bound processes operating at the edge of instability.This work establishes a foundational principle for how complex systems move energy, information, and structure without collapse.
Thomas S. Mitchell (Sat,) studied this question.