 This has led recent many-worlds proponents like David Wallace (2010 and 2012) to add explicit interpretative assumptions to the formalism of pure wave mechanics. In contrast with DeWitt, who seems to have taken worlds to be basic entities described by the global absolute state, Wallace takes the quantum state as basic, then seeks to characterize worlds as emergent entities represented in its structure. The analogy he gives is that pure wave mechanics describes the quantum state just as classical field theory describes physical fields (2010, 69). Worlds then are understood as physically real but contingently emergent entities that are identified with approximate substructures of the quantum state, or as Wallace puts it, “mutually dynamically isolated structures instantiated within the quantum state, which are structurally and dynamically ‘quasiclassical’” (2010, 70). Just a bit more carefully, one would expect such emergent worlds to be more or less isolated depending on the physical situation and properties one seeks to describe and the degree of decoherence in fact exhibited by the systems as characterized.