Sufficiency of background independence for meeting the Primary Motivation

Determine whether background independence—understood as the absence of fixed background spacetime structures and captured via diffeomorphism invariance, generally covariant action formulations, or related criteria—is sufficient to satisfy the requirement that a theory of quantum gravity take into account the lessons of general relativity within the Primary Motivation, or whether additional principles from general relativity must be incorporated.

Background

Background independence is widely treated as a desirable feature for quantum gravity, often serving as the main candidate for how a new theory should take into account lessons from general relativity. However, formalising background independence is subtle and multiple non-equivalent proposals exist, each with shortcomings.

The author highlights that, despite the prominence of background independence in guiding approaches like loop quantum gravity and causal set theory, it is unresolved whether this principle alone suffices to meet the stated objective of reconciling the lessons of GR and QM embodied in the Primary Motivation. This leaves open whether other GR principles should be required by a satisfactory quantum gravity.