Facts about moral disagreement and human evolution have both been said to exclude the possibility of moral knowledge, but the question of how these challenges interact has largely gone unaddressed. The paper aims to present and defend a novel version of the evolutionary “debunking” argument for moral skepticism that appeals to both types of considerations. This argument has several advantages compared to more familiar versions. The standard debunking strategy is to argue that evolutionary accounts of moral beliefs generate skeptical implications (...) because they attribute those beliefs to factors that are unrelated to their truth. That strategy is vulnerable to “third-factor” responses, which invoke first-order moral claims to challenge the assumption that Darwinian factors and the moral truths are really unrelated in that way. In contrast, our version is immune to those responses, as it does not proceed via assumptions about how Darwinian factors relate to the moral facts. Instead, it focuses on what evolutionary accounts of moral beliefs have to say about the fact that people often reach divergent moral beliefs. The argument thereby illustrates how the debunking strategy can join forces with the argument from moral disagreement. The combination of those strategies presents, we think, a challenge that is more formidable than when they are considered separately. (shrink)

People disagree about whether individuals in rich countries like the United States have an obligation to aid the world’s poorest people. A tempting thought is that this disagreement comes down to a non-moral matter. I argue that we should be suspicious of this view. Drawing on psychological evidence, I show that we should be more pessimistic about our ability to attribute the disagreement to a difference in factual beliefs.

Moral relativists often defend their view as an inference to the best explanation of widespread and deep moral disagreement. Many philosophers have challenged this line of reasoning in recent years, arguing that moral objectivism provides us with ample resources to develop an equally or more plausible method of explanation. One of the most promising of these objectivist methods is what I call the self-interest explanation, the view that intractable moral diversity is due to the distorting effects of our interests. In (...) this paper I examine the self-interest explanation through the lens of the famine debate, a well-known disagreement over whether we have a moral obligation to donate most of our income to the global poor. I argue that objectivists should reduce their confidence that the persistence of the famine debate is due to the distorting influence of self-interest. If my argument is on target, then objectivists may need to supply a stronger explanation of moral disagreement to defend their view against the threat of moral relativism. (shrink)

The most popular argument against moral realism is the argument from disagreement: if there are mind‐independent moral facts, then we would not expect to find as much moral disagreement as we in fact do; therefore, moral realism is false. In this paper, I develop the flipside of this argument. According to this argument from agreement, we would expect to find lots of moral disagreement if there were mind‐independent moral facts. But we do not, in fact, find much moral disagreement; therefore, (...) moral realism is false. I defend the argument, explain the empirical evidence that supports it, and show what makes this challenge novel and powerful. (shrink)

Moral disagreement is sometimes thought to pose problems for moral realism because it shows that we cannot achieve knowledge of the moral facts the realists posit. In particular, it is "fundamental" moral disagreement—that is, disagreement that is not due to distorting factors such as ignorance of relevant nonmoral facts, bad reasoning skills, or the like—that is supposed to generate skeptical implications. In this paper, we show that this version of the disagreement challenge is flawed as it stands. The reason is (...) that the epistemic assumptions it requires are incompatible with the possibility of fundamental disagreement. However, we also present an alternative reconstruction of the challenge that avoids the problem. The challenge we present crucially invokes the principle that knowledge requires "adherence". While that requirement is usually not discussed in this context, we argue that it provides a promising explanation of why disagreement sometimes leads to skepticism. (shrink)

An increasing number of moral realists and anti-realists have recently attempted to support their views by appeal to science. Arguments of this kind are typically criticized on the object-level. In addition, however, one occasionally also comes across a more sweeping metatheoretical skepticism. Scientific contributions to the question of the existence of objective moral truths, it is claimed, are impossible in principle; most prominently, because such arguments impermissibly derive normative from descriptive propositions, such arguments beg the question against non-naturalist moral realism, (...) science cannot inform conceptual accounts of moral judgements, and the conceptual is logically prior to the empirical. My main aim in this paper is to clarify and critically assess these four objections. Moreover, based on this assessment, I will formulate four general requirements that science-based arguments in favor of moral realism and anti-realism should meet. It will turn out that these arguments are limited in several ways, and that some existing arguments have been unsound. Yet it is still possible in principle for the empirical sciences to contribute to the moral realism/anti-realism debate. (shrink)

Almost all participants in the debate about the ethics of accidents with self-driving cars have so far assumed moral universalism. However, universalism may be philosophically more controversial than is commonly thought, and may lead to undesirable results in terms of non-moral consequences and feasibility. There thus seems to be a need to also start considering what I refer to as the “relativistic car” — a car that is programmed under the assumption that what is morally right, wrong, good, bad, etc. (...) is determined by the moral beliefs of one’s society or culture. My investigation of this idea involves six steps. First, I explain why and how the moral universalism/relativism debate is relevant to the issue of self-driving cars. Second, I argue that there are good reasons to consider accident algorithms that assume relativism. Third, I outline how a relativistic car would be programmed to behave. Fourth, I address what advantages such a car would have, both in terms of its non-moral consequences and feasibility. Fifth, I address the relativistic car’s disadvantages. Finally, I qualify and conclude my considerations. (shrink)

In this paper, I distinguish between two error theories of morality: one couched in terms of truth ; the other in terms of justification. I then present two arguments: the Poisoned Presupposition Argument for ET1; and the Evolutionary Debunking Argument for ET2. I go on to show how assessing these arguments requires paying attention to empirical moral psychology, in particular, work on folk metaethics. After criticizing extant work, I suggest avenues for future research.

Richard Nisbett and Dov Cohen’s (1996) influential account of “cultures of honor” speculates that honor norms are a socially-adaptive deterrence strategy. This theory has been appealed to by multiple empirically-minded philosophers, and plays an important role in John Doris and Alexandra Plakias’ (2008) antirealist argument from disagreement. In this essay, I raise four objections to the Nisbett-Cohen deterrence thesis, and offer another theory of honor in its place that sees honor as an agonistic normative system regulating prestige competitions. Since my (...) account portrays honor norms as radically different from liberal ones, it actually strengthens Doris and Plakias’ case in some respects: cultures of honor are not merely superficially different from Western liberal ones. Nonetheless, the persistent appeal of honor’s principles, and their moral plausibility in certain contexts, suggests not antirealism, but pluralism—a reply on behalf of realism that itself has considerable empirical support. (shrink)

Moral psychology investigates human functioning in moral contexts, and asks how these results may impact debate in ethical theory. This work is necessarily interdisciplinary, drawing on both the empirical resources of the human sciences and the conceptual resources of philosophical ethics. The present article discusses several topics that illustrate this type of inquiry: thought experiments, responsibility, character, egoism v . altruism, and moral disagreement.

I consider whether evolutionary explanations can debunk our moral beliefs. Most contemporary discussion in this area is centred on the question of whether debunking implications follow from our ability to explain elements of human morality in terms of natural selection, given that there has been no selection for true moral beliefs. By considering the most prominent arguments in the literature today, I offer reasons to think that debunking arguments of this kind fail. However, I argue that a successful evolutionary debunking (...) argument can be constructed by appeal to the suggestion that our moral outlook reflects arbitrary contingencies of our phylogeny, much as the horizontal orientation of the whale’s tail reflects its descent from terrestrial quadrupeds. An introductory chapter unpacks the question of whether evolutionary explanations can debunk our moral beliefs, offers a brief historical guide to the philosophical discussion surrounding it, and explains what I mean to contribute to this discussion. Thereafter follow six chapters and a conclusion. The six chapters are divided into three pairs. The first two chapters consider what contemporary scientific evidence can tell us about the evolutionary origins of morality and, in particular, to what extent the evidence speaks in favour of the claims on which debunking arguments rely. The next two chapters offer a critique of popular debunking arguments that are centred on the irrelevance of moral facts in natural selection explanations. The final chapters develop a novel argument for the claim that evolutionary explanations can undermine our moral beliefs insofar as they show that our moral outlook reflects arbitrary contingencies of our phylogeny. A conclusion summarizes my argument and sets out the key questions that arise in its wake. (shrink)