# Dimension and Dimensional Reduction in Quantum Gravity

## TL;DR

This paper reviews various approaches to quantum gravity that suggest spacetime becomes effectively two-dimensional at very short distances, exploring the implications and meaning of this dimensional reduction.

## Contribution

It synthesizes evidence from different quantum gravity theories indicating dimensional reduction and discusses its potential physical significance.

## Key findings

- Multiple quantum gravity approaches show effective two-dimensionality at small scales
- Dimensional reduction may have profound implications for the nature of spacetime
- The paper offers speculative ideas on the physical meaning of reduced dimensions

## Abstract

A number of very different approaches to quantum gravity contain a common thread, a hint that spacetime at very short distances becomes effectively two dimensional. I review this evidence, starting with a discussion of the physical meaning of "dimension" and concluding with some speculative ideas of what dimensional reduction might mean for physics.