Conclusions

Abstract

Abstract Brining things to a close, we have seen that there are multifarious definitions of background independence on the table, all of which are useful in their own ways, while nevertheless all facing their own distinct problem cases. We have also seen, using this plurality of definitions, that general relativity is not in any obvious sense distinguished from other theories of space and time by virtue of its background independence—indeed, on some accounts (in particular that in terms of the absence of absolute objects), general relativity fails to be background independent after all! Next, we’ve adapted our menu of definitions of background independence to the case of quantum theories of gravity, and have again found that the situation in certain cases (e.g., that of perturbative string theory) is more complex than one might initially have thought. As a result, it is not obviously correct to rule out certain approaches to quantum gravity on the basis of their lacking this quality. In this closing chapter, I reflect more broadly on these results: is the methodology of using intuitions and case studies to 'hone' definitions of background independence the correct one to follow? Should one be a pluralist about definitions of background independence? And to what other fields of cutting-edge physics might this methodology be applied?