Physics Diamond

The standard formulation of quantum mechanics combines deterministic unitary evolution with non-deterministic measurement postulates. Although operationally successful, this hybrid structure introduces internal tensions between continuity, probability, and physical law. In this work, we examine the standard postulates across five independent formalisms—the Schro¨dinger picture, the Heisenberg picture, the path integral formulation, the density matrix framework, and open-systems measurement theory. By identifying the load-bearing assumptions required to sustain intrinsic randomness, we reveal a deeper consistency condition implicit in all five approaches. When made explicit, this condition enforces a fully deterministic substrate underlying quantum evolution, with apparent stochasticity arising only from coarse-graining over unresolved degrees of freedom. No empirical predictions are altered. Instead, determinism emerges as the minimal completion of the standard formalism.