Constructing Physics From Measurements

We present a reformulation of fundamental physics - from a collection of independent axioms to the solution of a single optimization problem. Any experiment begins with an initial state preparation, involves some physical operation, and ends with a final measurement. Working from this structure, we maximize the entropy of final measurements relative to their preparations subject to an appropriate physical constraint. This optimization problem considers all possible predictive theories over all possible experiments, whilst being constrained by all possible measurements, and then automatically selects the exact physics we observe as the optimal solution. As a consequence of this formulation, rather than as separate postulates, we obtain quantum mechanics, general relativity, and the Standard Model gauge symmetries within a unified theory. Mathematical consistency further restricts valid solutions to 3+1 dimensions, suggesting why our universe exhibits this specific dimensionality. This reformulation reveals that the apparent complexity of modern physics, with its various forces, symmetries, and dimensional constraints, emerges naturally when optimizing over all possible ways of predicting measurements from preparations.