In this paper, I will argue that metaphysicians ought to utilize quantum theories of gravity as incubators for a future metaphysics. I will argue why this ought to be done and will present cases studies from the history of science where physical theories have challenged both the dogmatic and speculative metaphysician. I provide two theories of QG and demonstrate the challenge they pose to certain aspects of our current metaphysics; in particular, how they challenge our understanding of the abstract–concrete distinction. (...) I demonstrate how five different accounts of the distinction each fail to hold under the received interpretations of loop quantum gravity and string theory. The central goal of this paper is to encourage metaphysicians to look to physical theories, especially those involving cosmology such as string theory and loop quantum gravity, when doing metaphysics. (shrink)

The canonical formalism of general relativity affords a particularly interesting characterisation of the infamous hole argument. It also provides a natural formalism in which to relate the hole argument to the problem of time in classical and quantum gravity. In this paper we examine the connection between these two much discussed problems in the foundations of spacetime theory along two interrelated lines. First, from a formal perspective, we consider the extent to which the two problems can and cannot be precisely (...) and distinctly characterised. Second, from a philosophical perspective, we consider the implications of various responses to the problems, with a particular focus upon the viability of a `deflationary' attitude to the relationalist/substantivalist debate regarding the ontology of spacetime. Conceptual and formal inadequacies within the representative language of canonical gravity will be shown to be at the heart of both the canonical hole argument and the problem of time. Interesting and fruitful work at the interface of physics and philosophy relates to the challenge of resolving such inadequacies. (shrink)

It is argued that certain quantum theories of gravity — string theory, loop quantum gravity, non-commutative field theory — do not include spacetime as part of their fundamental ontology. There is a concern in the literature that theories of this kind are physically opaque and empirically incoherent. In this paper, I clarify and amend Huggett and Wüthrich’s argument against these claims. Whereas the content of this paper centres on the disappearance and re-emergence of spacetime in quantum gravity, much of the (...) philosophical work centres more generally on issues of (emergent) ontology and how this ontology can be extracted from formal theories, the role of formal derivations in justifying ontological relations, the nature of Kuhnian revolutions, and the application of these revolutions to quantum gravity. (shrink)