Papers in Progress

Symmetries in Physical Reasoning (draft of February 2010, comments welcome)

1. The concept of symmetry plays a central role in physical reasoning, but when one asks whether the inferences involving symmetry are justified one finds that the literature either contains no justification at all, or else that the justifications on offer are woefully lacking. Rather than conclude that these inferences are based on a mistake, though, my aim in this paper is to provide a “rational reconstruction” of this fragment of physical reasoning. The reconstruction consists of two stages. In the first stage I argue that one kind of inference involving symmetry is epistemically prior to the others, in the sense that justifying it is necessary and sufficient for justifying the others. In the second stage, I justify this epistemically prior inference by “reverse engineering”, asking what ‘symmetry’ could possibly mean if the inference is to be justifiable. The definition of ‘symmetry’ I arrive at differs from those found in the literature: I argue that far from being a concept amenable to definition in crisp, mathematical terms, it can only be adequately understood in terms of mental and counterfactual concepts.
   

On the Plurality of Grounds (REVISED draft of January 2010, comments welcome)

1. Recent metaphysics has contained a good deal of discussion about the relation of ground. In this paper I argue that it is an irreducibly plural relation, i.e. that when X is grounded in Y, both X and Y may be pluralities of entities or facts. That Y may be a plurality is well-known, but I argue that X may be a plurality too: there are cases in which a plurality of facts taken together are grounded in some underlying facts even though no member of of the plurality has a ground when taken individually. I argue that there are at least two examples of such pluralities: individualistic facts and facts about mass-in-kilograms. But regardless of those particular cases, the mere possibility that ground is plural in this way has significant implications for metaphysics. For the canonical strategy of arguing that a given aspect of the world is fundamental is to argue that it has no ground, but if X can be a plurality this argument is invalid: an aspect may have no ground but nonetheless be part of a plurality with a ground, in which case it would be a mistake to conclude that it is fundamental. I discuss some of the ways that this sort of mistake has permeated the metaphysics literature.
   

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Metaphysical Lessons of General Covariance (draft of May 2009, comments welcome)

1. Contemporary discussions of space-time substantivalism focus on the Hole Argument, an argument designed to show that substantivalism is false. The Hole Argument makes controversial assumptions about determinism and modality, so it is unsurprising that substantivalists have defended their view by denying those assumptions. In this paper I develop a new argument against space-time substantivalism which follows the spirit of the Hole Argument but makes none of the controversial assumptions about determinism and modality. As a result, the standard ways of responding to the Hole Argument are of no use when responding to this new argument. I finish the paper by outlining an anti-substantival view of space-time that the argument suggests.
   

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Absolutism vs Comparativism about Quantity (coming soon)

1. Is mass an intrinsic property of a material body, or do all facts about mass ultimately consist in facts about how material bodies are related to one another in mass? In this paper I argue that most discussions of this question have focused on considerations that are in fact of little relevance to the issue. Once the relevant considerations are identified, I argue that they favor the latter view.
   

Inquiry and Ignorance (coming soon)

1. What is the aim of empirical inquiry? In this paper I argue that it is not just to form beliefs with the normal epistemic virtues of being true, justified, rational, counting as knowledge and so on: in addition, I argue, we aim for our beliefs to represent the world in a very particular kind of way. If this is right, then even if our beliefs have all the normal epistemic virtues we could in principle fail to achieve the aim of inquiry by failing to represent the world in the right way. This state of “ignorance” has been largely ignored, but I argue that it is surprisingly widespread: we simply do not have the conceptual resources to represent certain aspects of the world in a way that would be required to fulfill the aim of inquiry.