Background Independence in Classical and Quantum Gravity

It is often claimed that Einstein's magnum opus---his 1915 theory of General Relativity---is distinguished from other theories of space and time in virtue of its background independence. It's also often claimed that background independence is an essential feature of any quantum theory of gravity. But are these claims true? This book aspires to offer definitive answers to both of these questions, by (a) charting the space of possible definitions of background independence, and (b) applying said definitions to various classical and quantum theories of gravity. The outcome, in brief, is as follows: General Relativity is not unique by virtue of its background independence (and, indeed, fails to be background independent on some popular definitions); moreover, the situation in the case of quantum theories of gravity is delicate, because (i) there are viable such theories which (by some accounts, at least) fail to be background independent, but also (ii) theories (e.g. perturbative string theory) which have often been dismissed for (allegedly) being background dependent in fact, on many accounts, are better classified as background independent. In giving these answers in rigorous detail, this book seeks to elevate the standards and generality of future discussions of background independence in the foundations of spacetime theories.

1 - Introduction
2 - Models and Gauge
3 - Classical Background Independence
4 - Classical Theories of Spacetime
5 - Quantum Theories of Spacetime
6 - Conclusions

James Read is an Associate Professor of Philosophy at the University of Oxford. He studied Physics and Philosophy at Oxford, and Mathematics at Cambridge, before completing a doctorate in Philosophy from Oxford in 2018. He works in the philosophy of physics, in particular on issues in the foundations of spacetime theories and symmetries. His work has won various international awards, including the Hanneke Janssen Prize and Clifton Memorial Prize.