Binding quantum matter and space-time, without romanticism

TL;DR

This paper argues that space-time might be fundamental rather than emergent from quantum gravity, reviewing models that challenge the need for emergent space-time and discussing the measurement problem in this context.

Contribution

It presents models suggesting space-time could be fundamental, challenging the common view of emergence from quantum gravity, and discusses implications for the measurement problem.

Findings

Models bypass the main objections to fundamental space-time

Space-time may be a basic aspect of reality, not emergent

Measurement problem considerations support fundamental space-time

Abstract

Understanding the emergence of a tangible 4-dimensional space-time from a quantum theory of gravity promises to be a tremendously difficult task. This article makes the case that this task may not have to be carried. Space-time as we know it may be fundamental to begin with. I recall the common arguments against this possibility and review a class of recently discovered models bypassing the most serious objection. The generic solution of the measurement problem that is tied to semiclassical gravity as well as the difficulty of the alternative make it a reasonable default option in the absence of decisive experimental evidence.