Fundamentality and Levels in Everettian Quantum Mechanics

Distinctions in fundamentality between different levels of description are central to the viability contemporary decoherence-based Everettian quantum mechanics (EQM). This approach theory characteristically combines a determinate fundamental reality (one universal wavefunction) with an indeterminate emergent (multiple decoherent worlds). In this chapter I explore how appeal and emergence can be understood within existing metaphysical frameworks, identify grounding concept as promising theoretical tools, use them characterize system explanatory (with associated laws nature) for EQM. structure encompasses extends ‘classical’ structure. The physics, chemistry, biology, etc. recovered, but they character potentially variable across Everett worlds. EQM invokes additional level, not present classical picture, novel potential role self-location interlevel metaphysics. When given modal realist interpretation, also makes trouble supervenience-based approaches levels.