Tobias Wilsch

This book investigates the idea that the sources of necessity—essence, laws, and logic—have the power to explain because they exert necessity, a modal force, on the facts. 'The Sources of Necessity' explores this idea through two interwoven themes: explanation and necessity. It develops a unified account of explanation and clarifies the distinctive explanatory contributions of each source. It examines the governing role of natural laws, the interaction between essences and logic in accounting for absolute necessity, and the existence and nature of metaphysical laws. On the theme of necessity, it argues for a primitivist and pluralist view about necessity, which in turn raises two thorny questions: ‘Why are the sources of necessity themselves necessary?’ and ‘Why are different kinds of necessity ordered by strength?’ To answer these questions, the book develops a rationalist view, proposing that contingent reality emerges from a cosmogenic sequence—one that unfolds from essences and logic, through the other sources, all the way to the realm of contingent facts.

Realists about laws of nature and their Humean opponents disagree on whether laws ‘govern’. An independent commitment to the ‘governing conception’ of laws pushes many towards the realist camp. Despite its significance, however, no satisfactory account of governance has been offered. The goal of this article is to develop such an account. I base my account on two claims. First, we should distinguish two notions of governance, ‘guidance’ and ‘production’, and secondly, explanatory phenomena other than laws are also candidates for governance. My goal is to develop a unified account which captures both guidance and production as well as the governance of phenomena, such as essence and logical consequence. The account of governance I develop belongs to the family of modal accounts, which was popularized by David Armstrong, but it also employs essentialist resources. If successful, this modal-essentialist account not only reveals the costs that proponents of governance incur, but it also puts that important notion on a solid theoretical foundation.

Could laws of nature be violated, in the sense that some proposition is both a law and false? I argue that opponents of regularity theories of laws should accept the metaphysical possibility of such genuine violations. I begin with a clarification of this claim. The main argument is then developed in three steps. I first argue that opponents of regularity theory should endorse the modal-essence view: certain modal principles are essential to the laws of nature. Second, I argue that the modal-essence view entails sophisticated modal primitivism. Third, I argue from sophisticated primitivism to the metaphysical possibility of genuine violations of laws.

Summary: The paper provides an argument for modal primitivism, the view that necessity is not defined and is therefore part of the structure of reality. It then raises the explanation-challenge for primitivists: how can modal truths be explained by hyper-intensional truths, if necessity is not defined in terms of hyper-intensional phenomena? To address the challenge, the paper introduces 'sophisticated modal primitivism' which gives a substantive analysis of the notion of a 'source of necessity'. The final part of the paper offers some applications of that novel piece of ideology.

The paper explores a deductive-nomological account of metaphysical explanation: some truths metaphysically explain, or ground, another truth just in case the laws of metaphysics determine the latter truth on the basis of the former. I develop and motivate a specific conception of metaphysical laws, on which they are general rules that regulate the existence and features of derivative entities. I propose an analysis of the notion of ‘determination via the laws’, based on a restricted form of logical entailment. I argue that the DN-account of ground can be defended against the well-known objections to the DN-approach to scientific explanation. The goal of the paper is to show that the DN-account of metaphysical explanation is a well-motivated and defensible theory

The article introduces and defends the Nomological Account of ground, a reductive account of the notion of metaphysical explanation in terms of the laws of metaphysics. The paper presents three desiderata that a theory of ground should meet: it should explain the modal force of ground, the generality of ground, and the interplay between ground and certain mereological notions. The bulk of the paper develops the Nomological Account and argues that it meets the three desiderata. The Nomological Account relies on two central notions: the notion of a ‘law of metaphysics’ and the notion of ‘determination via the laws’. The paper offers the constructional conception of the laws of metaphysics, on which the metaphysical laws are general principles that characterize construction–operations such as composition, constitution, or set-formation. The role of determination in the account is explained and some reductive approaches to the notion are sketched. The case for the Nomological Account presented in this article is also a case for the laws of metaphysics. Since the Nomological Account offers a promising approach to metaphysical explanation we should take the laws of metaphysics seriously