The Metaphysics of Moral Explanations

This chapter defends the view that general moral principles play an ineliminable role in moral explanations. More specifically, it argues that this view best makes sense of some intuitive data points, including the supervenience of the moral upon the natural. The chapter considers two alternative accounts of the nature and structure of moral principles: (i) “the nomic view,” on which moral principles are laws of metaphysics of the same broad kind as the laws that (plausibly) figure in metaphysical explanations more generally; and (ii) “moral platonism,” on which moral principles are facts about kind-applying (as opposed to particular-applying) moral properties. Along the way, the chapter criticizes the competing view that moral principles are not explanatory in the way just suggested. The chapter also considers a number of related issues, such as the distinction between metaphysical grounding and metaphysical analysis. It concludes by discussing the sense in which moral principles obtain of necessity.

Laws for Metaphysical Explanation

I argue that, just like causal explanation requires laws of nature, so metaphysical explanation requires laws of metaphysics. I offer a minimal rendition of the argument for laws of metaphysics, assuming nothing about grounding or essences, and little about explanation. And I offer a positive and minimal functional conception of the laws of metaphysics, coupled with an argument that some laws of metaphysics are fundamental.

Introduction

Chapter 1 explains the concept of time travel, clarifies the main question to be addressed, and previews the paradoxes to come. Section 1 explains the traditional view of time travel as involving a discrepancy between “personal” and “external” time. Section 2 contrasts this kind of time travel with other, purported examples of time travel. Section 3 distinguishes a number of different questions about time travel, including the question of whether or not time travel is compatible with the laws of metaphysics—particularly those having to do with the nature of time, freedom, causation, and identity. Finally, section 4 provides an outline of the rest of the book by introducing some of the key paradoxes to be addressed. Other topics in this chapter include time, causation, and metaphysical grounding.

Paradoxes of Time Travel

Paradoxes of Time Travel is a comprehensive study of the philosophical issues raised by the possibility of time travel. The book begins, in Chapter 1, by explaining the concept of time travel and clarifying the central question to be addressed: Is time travel compatible with the laws of metaphysics and, in particular, the laws concerning time, freedom, causation, and identity? Chapter 2 then explores the various temporal paradoxes, including the double-occupancy problem, the no-destination argument, and the famous twin paradox of special relativity. Chapters 3 and 4 focus on the paradoxes of freedom, including various versions of the grandfather paradox. Chapter 5 covers causal paradoxes, including the bootstrapping paradox, the problems of backward causation, and the various puzzles raised by causal loops. Chapter 6 then concludes by looking at various paradoxes of identity. This includes a discussion of different theories of change and persistence, and an exploration of the various puzzles raised by self-visitation.