Abstract

While there are some empirical problems that could suggest the need for a theory of quantum gravity, most of these are not standardly taken as motivations for seeking a new theory. Rather, the quest for a theory of quantum gravity has been primarily motivated, guided, and constrained by philosophical and theoretical concerns. A critical examination of these can help us better understand what the theory is supposed to achieve—and, further, what it should be expected to achieve. On the other hand, there are various approaches towards finding a theory of quantum gravity, with different aims, methods, and starting-points—they disagree on what the theory is supposed to be like. A relevant question is then: what is it that unites these approaches such that we classify them as approaches to quantum gravity? This paper argues that a basic characterisation of the theory can be given in terms of the minimal shared motivation across these different approaches, and that this itself can be seen as motivated by various other problems that have been appealed to as reasons for seeking a theory of quantum gravity.