The fact that debunkers can turn to the argument from disagreement for help is ofcourse not a surprise. After all, both types of challenge basically pursue the same,skeptical conclusion. What I have tried to show, however, is that they are related in amore intimate way.

Metaethical debunking arguments often conclude that no moral belief is epistemically justified. Early versions of such arguments largely relied on metaphors and analogies and left the epistemology of debunking underspecified. Debunkers have since come to take on substantial and broad-ranging epistemological commitments. The plausibility of metaethical debunking has thereby become entangled in thorny epistemological issues. In this thesis, I provide a critical yet sympathetic evaluation of the prospects and challenges facing such arguments in light of this development. In doing so, (...) I address the following central question: how could genealogical information undermine the epistemic justification of moral beliefs? In Part I, I begin answering the central question by extracting explicit and implicit epistemic principles from three popular debunking arguments. These arguments, due to Gilbert Harman, Richard Joyce, and Sharon Street, generate principles concerning ontological parsimony, explanatory dispensability, epistemic insensitivity, lack of epistemic safety, unexplained reliability, epistemic coincidences, and explanatory constraints on rational belief. Having set out the principles tasked with explaining how genealogical information undermines, Part II of the thesis seeks to evaluate whether debunking arguments built on them succeed. To this end, I consider two types of challenges faced by such arguments. First, there are strategies that attempt to block global moral debunking arguments. I argue that one popular such strategy, the so-called ‘third-factor strategy’, has been misunderstood. When understood correctly, it is of no help in answering debunking arguments. I then flesh out an alternative and more promising strategy for blocking such arguments. I then turn to internal challenges facing debunkers, particularly those who rely on ‘explanationist’ principles. I argue that explanationist debunking arguments, as well as most others, fall prey to one or more of four internal challenges: the implausibility of first-order epistemic principles, the threat of overgeneralization, the threat of self-defeat, and the need for costly metaepistemic commitments. I conclude that current debunking arguments fail to establish that no moral belief is justified. By analyzing why existing arguments fail, I develop two conditions of adequacy that debunkers must satisfy in order to navigate the internal challenges successfully. I end by suggesting future directions that debunkers should pursue to rehabilitate the prospects for global moral debunking arguments. (shrink)

A common anti-realist strategy is to argue that moral realism (or at least the non-naturalist form of it) should be abandoned because it cannot adequately make room for moral knowledge and justified moral belief, for example in view of an evolutionary account of the origins of moral beliefs or of the existence of radical moral disagreement. Why is that (alleged) fact supposed to undermine realism? I examine and discuss three possible answers to this question. According to the answer that I (...) think holds most promise, it undermines realism because it renders realism “epistemically incoherent” (in a sense explicated in the paper), and a central aim of the paper is to elaborate and defend that suggestion against certain objections. I end by briefly commenting on the more general significance of the discussion, by considering some other areas (epistemology and vagueness) where similar questions might be raised. (shrink)

Many metaethicists assume that our normative judgments are both by and large true, and the product of causal forces. In other words, many metaethicists assume that the set of normative judgments that causal forces have led us to make largely coincides with the set of true normative judgments. How should we explain this coincidence? This is what Sharon Street (2006) calls the practical/theoretical puzzle. Some metaethicists can easily solve this puzzle, but not all of them can, Street argues; she takes (...) the puzzle to constitute a specific challenge for normative realism. In this article I elucidate Street's puzzle and outline possible solutions to it, framed in terms of a general strategy for reasoning about coincidences. I argue that the success of Street's challenge crucially depends on how we set the ‘reference class’ of normative judgments that we could have endorsed, assuming realism. I conclude that while the practical/theoretical puzzle falls short of posing a general challenge for normative realism, it can be successful as a selective challenge for specific realist views. (shrink)

Anti-realism is often claimed to be preferable to realism on epistemological grounds: while realists have difficulty explaining how we can ever know claims if we are realists about it, anti-realism faces no analogous problem. This paper focuses on anti-realism about normativity to investigate this alleged advantage to anti-realism in detail. I set up a framework in which a version of anti-realism explains a type of modal reliability that appears to be epistemologically promising, and plausibly explains the appearance of an epistemological (...) advantage to realism. But, I argue, this appearance is illusory, and on closer investigation the anti-realist view does not succeed in explaining the presence of familiar epistemological properties for normative belief like knowledge or the absence of defeat. My conclusion on the basis of this framework is that there is a tension in the anti-realist view between the urge to idealize the conditions in which normative beliefs ground normative facts, and a robust kind of reliability that normative belief can have if the anti-realist resists these idealizations. (shrink)

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)

Debunking arguments use empirical evidence about our moral beliefs - in particular, about their causal origins, or about how they depend on various causes - in order to reach an epistemic conclusion about the trustworthiness of such beliefs. In this thesis, I investigate the scope and limits of debunking arguments, and their implications for what we should believe about morality. I argue that debunking arguments can in principle work - they are based on plausible epistemic premises, and at least some (...) of them avoid putative problems concerning regress and redundancy. However, I also argue that some debunking arguments fall short because they are insufficiently supported by the empirical evidence. By considering different objections, analyses, and a case study, I explore the conditions for a successful debunking argument. (shrink)

I reply to an influential objection to evolutionary debunking arguments against moral realism. According to this objection, our capacity for autonomous rational reflection allows us to grasp moral truths independently of distorting evolutionary influences, so those influences do not prevent us from having moral knowledge. I argue that rational moral reflection is not, in fact, autonomous from evolutionary influences, since it depends on our evolved, pre-reflective grasp of moral properties. I then consider and reject the suggestion that realists can supply (...) an autonomous foundation for rational moral reflection or do without any such foundation. Next, I address the allegation that my arguments have skeptical implications for rational reflection in non-moral domains. Finally, I conclude with a gesture toward a more promising route for realists who oppose debunking arguments. (shrink)

This is a draft of a chapter that has been accepted for publication by Oxford University Press in the forthcoming book "Ethics and Explanation", edited by Neil Sinclair and Uri Leibowitz due for publication in 2016.