Hume seems to claim that there does not exist a valid argument that has all non-ethical sentences as premises and an ethical sentence as its conclusion. Starting with Prior, a number of counterexamples to this claim have been proposed. Unfortunately, all of these proposals are controversial. Even the most plausible have a premise that seems like it might be an ethical sentence or a conclusion that seems like it might be non-ethical. Since it is difficult to tell whether any of (...) these counterexamples are genuine, we need a taxonomy that sorts out ethical sentences from non-ethical ones. We need to know the difference between an ‘Is’ and an ‘Ought’. In the first part of the paper, I establish the need for a taxonomy. I consider some of the most influential ‘Is’–‘Ought’ derivations. These include proposals by Prior and Searle. I argue that each proposal has a premise whose status as ethical or non-ethical is difficult to determine. In the second part of the paper, I consider taxonomies proposed by Karmo and Maitzen. I argue against both taxonomies. I end with the claim that we need a taxonomy of ethical sentences and that none of the current proposals are adequate. (shrink)

The central question for this dissertation is, how do we do moral philosophy well from within a broadly naturalist framework? Its main goal is to lay the groundwork for a methodological approach to moral philosophy that integrates traditional, intuition-driven approaches to ethics with empirical approaches that employ empirical data from biology and cognitive science. Specifically, it explores what restrictions are placed on our moral theorizing by findings in evolutionary biology, psychology, neuroscience, and other fields, and how we can integrate this (...) data while still offering a fully normative account of ethics. To that end, the dissertation explores the methodological assumptions behind both traditional and more empirical or experimental approaches to ethics, to find where these assumptions cannot be properly supported and need to be re-examined. Chapter 1 explores the science-based objections that have been raised to traditional approaches, with a particular focus on questions concerning the reliability of moral intuitions. Chapter 2 examines three fundamental assumptions supporting the empirical approach to moral philosophy, and how those assumptions ultimately do not fit with how we ought to understand the project of ethics. In chapter 3, I discuss the fact/value distinction, and the restrictions that are placed on our moral theorizing by our commitment to this distinction. Chapter 4 offers a defense of ‘companions in guilt’ arguments, and uses these arguments to draw an analogy between moral philosophy and epistemology that will be used to help defend moral philosophy against empirical debunking arguments. Chapter 5 explores the ways in which epistemologists’ methods of incorporating empirical data into their research while maintaining the normativity of their accounts can be adapted to allow moral philosophers to do the same, and brings together the various methodological concerns addressed up to this point to lay out a methodological approach I call empirically-informed moral philosophy. (shrink)

The appealing principle that you can't get an ‘ought’ from an ‘is’, sometimes called Hume's Guillotine , faces a well-known challenge: it must give a clear account of the distinction between normative and descriptive sentences while dodging counter-examples. I argue in this paper that recent efforts to answer this challenge fail because the distinction between normative and descriptive sentences cannot be described well enough to be of any help. As a result, no version of the principle is both true and (...) adequate. Yet a different principle—that no normative terms are synonymous with any descriptive terms—can satisfy much of the motivation we had for defending Hume's Guillotine in the first place. I show briefly how this second principle can explain why is-ought arguments are invalid, block some attempted deductive justifications of beliefs with normative terms, and create an explanatory advantage for moral non-cognitivism. Just so, giving up Hume's Guillotine is the prudent thi.. (shrink)