Spacetime Composition, Intuition and Familiarity

Abstract

Recent approaches to quantum gravity suggest that spacetime is not a fundamental entity but rather emerges from a non-spatiotemporal structure. To conceptualise how spacetime might emerge, it has been suggested that we should think of spacetime as being mereologically composed of spacetime regions which are in turn composed of non- spatiotemporal parts. However, Baron (2021) has argued that even if spacetime composition can be shown to be coherent, it would still be different from how we ordinarily conceive the mereology of concrete objects, and thus spacetime composition is unfamiliar. In this paper, I argue that this argument rests on the false premise that our intuitions apply equally to all domains. I then reformulate four principles that are taken to be intuitive for mereological composition. In their original formulations, these principles are violated by spacetime composition. But once reformulated, the tension with spacetime composition dissolves. I also show that these reformulations still satisfy our intuitions in the domain of everyday life but also extend beyond it into other domains. As a result, I maintain that spacetime composition is at least somewhat familiar with potential that its familiarity will grow in the future. Therefore, there is no reason to reject it as unfamiliar.