What criteria should be used to evaluate theories of emergence properties?

What criteria do people use to decide if a theory in physics is successful?For special relativity, general relativity, and quantum theory, highly precise measurements can be performed and compared to predictions of the theory. For example, Quantum Electrodynamics (QED) gives a value for the magnetic moment of the electron that agrees with experiment, to within one part in a trillion. However, for complex systems and emergent properties we do not have the luxury of such clear-cut criteria for deciding the success of a theory.Almost everyone would agree that the BCS theory of superconductivity is a smashing success. But it cannot predict whether a specific material is a superconductor. Its best predictions for elemental superconductors agree with experiment within a few per cent. Nevertheless, BCS is deemed successful because it gives a quantitative description of a wide range of thermodynamic, transport, and NMR properties for diverse materials. BCS is also consistent with…

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