One time, two times, or no time?

TL;DR

This paper explores the theoretical possibility of having one, two, or no physical times within quantum gravity frameworks, particularly loop quantum gravity, and discusses how our experience of time can emerge from these models.

Contribution

It analyzes the conceptual implications of multiple or absent times in quantum gravity and proposes a way to reconcile these with our temporal experience.

Findings

Multiple times or no time are plausible in quantum gravity models.

Emergence of time involves negotiating atemporal and temporal concepts.

Supports the idea that our manifestly temporal world can arise from non-temporal models.

Abstract

Contemporary research programs in fundamental physics appear to suggest that there could be two (physical) times---or none at all. This essay articulates these possibilities in the context of quantum gravity, and in particular of cosmological models developed in an approach called `loop quantum gravity', and explains how they could nevertheless underwrite our manifestly temporal world. A proper interpretation of these models requires a negotiation of an atemporal and a temporal sense of the emergence of (space)time.