# Classical and quantum: a conflict of interest

## TL;DR

This paper discusses fundamental conflicts between quantum theory and classical general relativity, suggesting that these conflicts challenge the idea of deriving quantum gravity through quantization of classical gravity, and pointing towards noncommutative geometry.

## Contribution

It identifies three core conflicts between quantum theory and classical gravity, proposing that these issues imply the need for a noncommutative geometric framework for space-time.

## Key findings

- Quantum nonlocality conflicts with space-time structure.
- The problem of time complicates quantum gravity.
- Quantum measurement problem impacts gravity theories.

## Abstract

We highlight three conflicts between quantum theory and classical general relativity, which make it implausible that a quantum theory of gravity can be arrived at by quantising classical gravity. These conflicts are: quantum nonlocality and space-time structure; the problem of time in quantum theory; and the quantum measurement problem. We explain how these three aspects bear on each other, and how they point towards an underlying noncommutative geometry of space-time.