The multiple realizability of general relativity in quantum gravity
arXiv:2005.05055 · doi:10.1007/s11229-019-02382-8
Abstract
Must a theory of quantum gravity have some truth to it if it can recover general relativity in some limit of the theory? This paper answers this question in the negative by indicating that general relativity is multiply realizable in quantum gravity. The argument is inspired by spacetime functionalism - multiple realizability being a central tenet of functionalism - and proceeds via three case studies: induced gravity, thermodynamic gravity, and entanglement gravity. In these, general relativity in the form of the Einstein field equations can be recovered from elements that are either manifestly multiply realizable or at least of the generic nature that is suggestive of functions. If general relativity, as argued here, can inherit this multiple realizability, then a theory of quantum gravity can recover general relativity while being completely wrong about the posited microstructure. As a consequence, the recovery of general relativity cannot serve as the ultimate arbiter that decides which theory of quantum gravity that is worthy of pursuit, even though it is of course not irrelevant either qua quantum gravity. Thus, the recovery of general relativity in string theory, for instance, does not guarantee that the stringy account of the world is on the right track; despite sentiments to the contrary among string theorists.
arXiv comment30 pages. To appear in Synthese
References in corpus (44)
- The Large N Limit of Superconformal Field Theories and Supergravity
- Holographic Derivation of Entanglement Entropy from AdS/CFT
- The World as a Hologram
- Microscopic Origin of the Bekenstein-Hawking Entropy
- Area laws for the entanglement entropy - a review
- Thermodynamics of Spacetime: The Einstein Equation of State
- On the Origin of Gravity and the Laws of Newton
- The holographic principle
- Towards a derivation of holographic entanglement entropy
- Cool horizons for entangled black holes
- Generalized gravitational entropy
- Quantum thermalization through entanglement in an isolated many-body system
- Building up spacetime with quantum entanglement
- Thermodynamical Aspects of Gravity: New insights
- Gravity and the Thermodynamics of Horizons
- Emergent Gravity and the Dark Universe
- Gravitation from Entanglement in Holographic CFTs
- Gravitational Dynamics From Entanglement "Thermodynamics"
- Holographic Entanglement Entropy
- Equipartition of energy in the horizon degrees of freedom and the emergence of gravity
- Entanglement Equilibrium and the Einstein Equation
- Solving the Schwarzian via the Conformal Bootstrap
- Sakharov's induced gravity: a modern perspective
- Emergent spacetime and empirical (in)coherence
- D-branes and the Standard Model
- Conformal Bootstrap, Universality and Gravitational Scattering
- Conceptual Aspects of Gauge/Gravity Duality
- Raiders of the lost spacetime
- Emergent Models for Gravity: an Overview of Microscopic Models
- Loop Quantum Gravity, Exact Holographic Mapping, and Holographic Entanglement Entropy
- Emergence in Holographic Scenarios for Gravity
- Bulk Entanglement Gravity without a Boundary: Towards Finding Einstein's Equation in Hilbert Space
- Dualities and Emergent Gravity: Gauge/Gravity Duality
- Spacetime thermodynamics without hidden degrees of freedom
- Entanglement Thermodynamics
- Gluing polyhedra with entanglement in loop quantum gravity
- Target Space Space
- Entanglement Entropy in Causal Set Theory
- Einstein Equation from Covariant Loop Quantum Gravity in Semiclassical Continuum Limit
- Group Field theory and Tensor Networks: towards a Ryu-Takayanagi formula in full quantum gravity
- Classical aspects of Hawking radiation verified in analogue gravity experiment
- Spacetime Equals Entanglement
- Horizon Thermodynamics from Einstein's Equation of State
- A critical look at strings