Martin Glazier

The question of what exists is often seen as one of the metaphysician’s primary concerns—an ontological stance is a central and basic component of a great many positions in metaphysics. Consider, in particular, the debate surrounding the metaphysics of time: the question of whether non-present entities exist is typically thought of as one of the fundamental issues at stake in the debate, with each position on the nature of time consisting in part of an answer to this question of ontology. My purpose in this paper will be to raise some worries about this focus on ontology, and to sketch an alternative approach to conceptualizing the debate—one that I think can help us get a clearer and deeper understanding of the fundamental issues at stake. I’ll focus in particular on the case of time and the ontology of non-present objects, but the framework I present is ultimately meant to apply more broadly to a range of debates involving ontology. On the framework I propose, the basic question at stake in this and other analogous debates is the following: Of the various perspectives we might adopt on reality, which perspective is fundamental? I’ll explain what this means and how it can help us reconceptualize the relevant metaphysical issues.

We define a notion of difference-making for partial grounds of a fact in rough analogy to existing notions of difference-making for causes of an event. Using orthodox assumptions about ground, we show that it induces a non-trivial division with examples of partial grounds on both sides. We then demonstrate the theoretical fruitfulness of the notion by applying it to the analysis of a certain kind of putative counter-example to the transitivity of ground recently described by Jonathan Schaffer. First, we show that our conceptual apparatus of difference-making enables us to give a much clearer description than Schaffer does of what makes the relevant instances of transitivity appear problematic. Second, we suggest that difference-making is best seen as a mark of good grounding-based explanations rather than a necessary condition on grounding, and argue that this enables us to deal with the counter-example in a satisfactory way. Along the way, we show that Schaffer’s own proposal for salvaging a form of transitivity by moving to a contrastive conception of ground is unsuccessful. We conclude by sketching some natural strategies for extending our proposal to a more comprehensive account of grounding-based explanations.

Explanatory realism is the position that all explanations give information about whatever metaphysically determines the explanandum. This view is popular and plays a central role in metaphysics, but in this paper I argue that explanatory realism is false. In Sect. 1 I introduce explanatory realism in its weak and strong versions, and discuss the argumentative work that explanatory realism is used for in contemporary metaphysics. In Sect. 2 I present a series of problem cases for explanatory realism, including explanation by analogy, explanations involving rules, reduction ad absurdum explanations and certain statistical explanations. In Sect. 3 I consider and reject two modified versions of explanatory realism: the position that explanatory realism is true only of explanation in metaphysics, and the position that determinative explanation is the most complete form of explanation. In conclusion I consider explanatory antirealism and explanatory pluralism as alternatives to explanatory realism.

Attempts to elucidate grounding are often made by connecting grounding to metaphysical explanation, but the notion of metaphysical explanation is itself opaque, and has received little attention in the literature. We can appeal to theories of explanation in the philosophy of science to give us a characterization of metaphysical explanation, but this reveals a tension between three theses: that grounding relations are objective and mind-independent; that there are pragmatic elements to metaphysical explanation; and that grounding and metaphysical explanation share a close connection. Holding fixed the mind-independence of grounding, I show that neither horn of the resultant dilemma can be blunted. Consequently, we should reject the assumption that grounding relations are mind-independent.

Humeans and anti-Humeans agree that laws of nature should explain scientifically particular matters of fact. One objection to Humean accounts of laws contends that Humean laws cannot explain particular matters of fact because their explanations are harmfully circular. This article distinguishes between metaphysical and semantic characterizations of the circularity and argues for a new semantic version of the circularity objection. The new formulation suggests that Humean explanations are harmfully circular because the content of the sentences being explained is part of the content of the sentences doing the explaining. I describe the nature of partial content and demonstrate how this account of partial content renders Humean explanations ineffective while sparing anti-Humean explanations from the same fate. _1_ Introduction _2_ Standard Formulations of the Circularity Charge _3_ Humean Responses _4_ Semantic Characterizations of the Circularity Worry _4.1_ Hempel and Oppenheim’s semantic circularity concern _4.2_ A new version of the semantic circularity charge _4.3_ Partial content as a guide to circularity _5_ Humean Responses to the Semantic Circularity Charge _5.1_ Smuggling in metaphysics through the back door? _5.2_ Do anti-Humean laws fare any better? _5.3_ The over-generalization concern _6_ Conclusion Appendix