Spacetime Emergence: Collapsing the Distinction Between Content and Context?

Abstract

Several approaches to developing a theory of quantum gravity suggest that spacetime—as described by general relativity—is not fundamental. Instead, spacetime is supposed to be explained by reference to the relations between more fundamental entities, analogous to ‘atoms’ of spacetime, which themselves are not (fully) spatiotemporal. Such a case may be understood as emergence of content: a ‘hierarchical’ case of emergence, where spacetime emerges at a ‘higher’, or less-fundamental, level than its ‘lower-level’ non-spatiotempral basis. But quantum gravity cosmology also presents us with the possibility of emergence of context: where spacetime emerges from some ‘prior’ non-spatiotemporal state (replacing the Big Bang). I present a general conception of emergence which is plausibly able to accommodate both pictures. This is a positive conception that does not rely on a failure of reduction or explanation in any sense (indeed, reduction is a necessary feature of quantum gravity, and is useful in understanding emergence in this case). I also consider the possibility that the distinction between content- and context- based explanations is blurred, or usefully ‘collapsed’, in the case of spacetime emergence.