Debunking arguments are arguments that seek to undermine a belief or doctrine by exposing its causal origins. Two prominent proponents of such arguments are the utilitarians Joshua Greene and Peter Singer. They draw on evidence from moral psychology, neuroscience, and evolutionary theory in an effort to show that there is something wrong with how deontological judgments are typically formed and with where our deontological intuitions come from. They offer debunking explanations of our emotion-driven deontological intuitions and dismiss complex deontological theories (...) as products of confabulatory post hoc rationalization. Through my discussion of Greene and Singer’s empirically informed debunking of deontology, I introduce the distinction between two different types of debunking arguments. The first type of debunking argument operates through regular undercutting defeat, whereas the second type relies on higher-order evidence. I argue that the latter type of debunking argument, of which the argument from confabulation is an example, is objectionably sloppy and therefore inadmissible in academic discussion. (shrink)

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)