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 \textit{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 \textit{context}: where spacetime emerges from some `prior' non-spatiotemporal state (replacing the Big Bang), due to particular conditions in the early universe. 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. (shrink)

This is the second part of an overview article on fundamentality in metaphysics and the philosophy of physics. Here, the notion of fundamentality is looked at from the viewpoint of the philosophical analysis of physics and physical theories. The questions are considered (1) whether physics can be regarded as fundamental with respect to other sciences, and in what sense; (2) what the label ‘fundamental physics’ should exactly be taken to mean; (3) on what grounds a particular physical theory should be (...) considered fundamental; (4) what should be regarded as fundamental according to particular theories of physics; and (5) what indications come from contemporary physics concerning the fundamental structure of reality. (shrink)

Critics frequently target Ernest Nagel’s model of reduction for its purported inadequacy in addressing the issue of approximation. In response, proponents of Nagel’s model have integrated approximations into the more comprehensive Generalized Nagel-Schaffner model, or the GNS model. However, this article contends that the pertinent criticisms and responses are both misplaced: There are no barriers to Nagel’s model incorporating approximations, and it assimilates them in a manner distinctly dissimilar to the approach of the GNS model. Indeed, Nagel’s model is fundamentally (...) _static_, providing invariant formal and informal conditions for reduction; and it is the _dynamic_ history of science that fulfills relevant conditions for reduction, thereby achieving different _degrees of reductive success_. Consequently, approximations are essentially extraneous to Nagel’s model, since they pertain chiefly to temporally based scientific knowledge and concern merely the _means_ (e.g., approximate or exact deductions) of fulfilling the conditions for reduction within specific problem contexts. This article also develops a Nagelian treatment of approximation, demonstrating how distinctive types of approximations aid in fulfilling various conditions for reduction and contribute to different degrees of reductive success. Two case studies are presented to illustrate the Nagelian treatment: The first examines the specific heat ratio anomaly within the traditional endeavor of reducing thermodynamics to statistical mechanics, and the second addresses the consumption puzzle in the context of reducing macroeconomics to microeconomics. (shrink)