The Ethics within Metaphysics

Abstract

This dissertation consists of three chapters at the intersection of ethics and metaphysics. In the first chapter, I put forward a new theory of personal identity, give arguments for it, and defend it from objections. In the first part, I argue that the two most prominent theories of personal identity, the psychological theory and the physical theory, do not satisfy some constraints on any acceptable theory: that personal identity be all-or-nothing, determinate, principled, and substantive. I then put forward a new theory, the phenomenal theory, on which personal identity is determined by the uninterrupted continuity of a stream of consciousness. I argue that this theory does satisfy all the desiderata, and is as such a better theory. In the second part, I argue that the phenomenal theory also solves the problem of fission cases, because there are no cases of phenomenal fission. In the third and last part, I consider the objection that, on the phenomenal theory, we do not survive interruptions of consciousness such as sleep; I argue that this objection doesn’t succeed in refuting the theory. In the second chapter, I generalize a debate about laws of nature to the domains of metaphysics and ethics. Patterns in the natural world lead us to the postulation of laws. A metaphysical dispute arises as to whether these laws are mere summaries of the mosaic (as the Humean would have it), or whether they govern the mosaic (as the Anti-Humean would have it). In this paper, I first argue that similarly, patterns in the metaphysical and ethical facts should lead us to the postulation of metaphysical and ethical laws, which are the proper subject of metaphysical and ethical inquiry. Then, I argue that the Humean/Anti-Humean debate also arises when it comes to metaphysical and ethical laws. Finally, I argue in favor of the Anti-Humean conception of metaphysical and ethical laws, both adapting standard arguments used in the debates about laws of nature, and with new arguments specific to metaphysics and ethics. In the third chapter, I investigate conflicts between ethics and metaphysics. Sometimes, a metaphysical theory has revisionary ethical consequences: for example, some have thought that modal realism entails that there are no moral obligations. In these cases, one may be tempted to reject the metaphysical theory on the grounds that it conflicts with commonsensical ethics. This is an ethics-to-metaphysics inference. My claim is that this inference is in general irrational, and that the fact that a metaphysical theory has highly revisionary ethical consequences is no reason at all to reject the theory. I argue for this claim on the basis of general epistemic principles about the transmission of justification, and what makes for a good argument. Furthermore, I argue that my account can explain why a certain narrow class of ethics-to-metaphysics inferences are rational.