Undercutting Defeat: When it Happens and Some Implications for Epistemology

Although there is disagreement about the details, John Pollock’s framework for defeat is now part of the received wisdom in analytic epistemology. Recently, however, cracks have appeared in the consensus, particularly on the understanding of undercutting defeat. While not questioning the existence of undercutting defeat, Scott Sturgeon argues that undercutting defeat operates differently from rebutting. Unlike the latter, undercutting defeat, Sturgeon claims, occurs only in conjunction with certain higher-order contributions, i.e., with beliefs about the basis on which one does or would believe. Sturgeon concludes that Pollock misconceives undercutting defeat. I argue that in the case of defeat of inferential justification, undercutting defeat is a genuine phenomenon and takes roughly the shape Pollock suggests, not needing help from higher-order beliefs or justifications. However, I agree with Sturgeon that for noninferential justification the Pollockian account is in trouble. I try to explain why there should be this difference. This difference in defeaters has important implications for epistemology. In a final section, I use the defeat-related difference between inferential and noninferential justification to argue that there is less noninferential perceptual or testimonial justification than is commonly thought

Disqualifying ‘Disqualifiers’

In addition to the notion of defeat, do we need to expand the epistemological repertoire used in accounting for the context dependence of justification? It has recently been argued that we ought to admit a hitherto unrecognized fundamental epistemic kind called ‘disqualifiers’. Disqualifiers are taken to be not reducible to any other epistemic notion. Rather, they are meant to be primitive. If this is correct, it is a surprising and novel discovery, and so it is worthy of further epistemological investigation. In this paper I shall first argue that the cases given do not motivate positing the notion of a disqualifier. Conclusions drawn about the existence of disqualifiers do not follow from the considerations advanced. Second, I shall directly argue that an essential core claim of those who would posit disqualifiers, that so-called disqualifiers actually do prevent epistemic bases from conferring justification, is false. In sum, I shall argue that there are no disqualifiers

The Hardest Paradox for Closure

According to the principle of Conjunction Closure, if one has justification for believing each of a set of propositions, one has justification for believing their conjunction. The lottery and preface paradoxes can both be seen as posing challenges for Closure, but leave open familiar strategies for preserving the principle. While this is all relatively well-trodden ground, a new Closure-challenging paradox has recently emerged, in two somewhat different forms, due to Marvin Backes (2019a) and Francesco Praolini (2019). This paradox synthesises elements of the lottery and the preface and is designed to close off the familiar Closure-preserving strategies. By appealing to a normic theory of justification, I will defend Closure in the face of this new paradox. Along the way I will draw more general conclusions about justification, normalcy and defeat, which bear upon what Backes (2019b) has dubbed the ‘easy defeat’ problem for the normic theory

Reasons for Reliabilism

One leading approach to justification comes from the reliabilist tradition, which maintains that a belief is justified provided that it is reliably formed. Another comes from the ‘Reasons First’ tradition, which claims that a belief is justified provided that it is based on reasons that support it. These two approaches are typically developed in isolation from each other; this essay motivates and defends a synthesis. On the view proposed here, justification is understood in terms of an agent’s reasons for belief, which are in turn analyzed along reliabilist lines: an agent's reasons for belief are the states that serve as inputs to their reliable processes. I show that this synthesis allows each tradition to profit from the other's explanatory resources. In particular, it enables reliabilists to explain epistemic defeat without abandoning their naturalistic ambitions. I go on to compare my proposed synthesis with other hybrid versions of reliabilism that have been proposed in the literature

The Evolution of Defeaters: A Taxonomy

It has been widely argued that reasons for a belief come in degrees but not much literature has focused on the idea that defeaters for justification toward those beliefs also come in degrees. The aim of this paper is to explore epistemic defeasibility and construct a taxonomy for epistemic defeaters. This paper argues that epistemic defeaters undergo an evolutionary process before becoming what they are commonly labeled, such as rebutting and undercutting. I argue that within some stages of this process, there can be different degrees of defeat. This paper focuses on defeaters for justification, expands on the account of partial defeaters and offers a solution to reliabilism’s problem with defeat. The main aim of this taxonomy is to provide a framework that allows (most) epistemic theories to accept solely on the basis of epistemic defeasibility

Debunking Objective Consequentialism: The Challenge of Knowledge-Centric Anti-Luck Epistemology

I explain why, from the perspective of knowledge-centric anti-luck epistemology, objective act consequentialist theories of ethics imply skepticism about the moral status of our prospective actions and also tend to be self-defeating, undermining the justification of consequentialist theories themselves. For according to knowledge-centric anti-luck epistemology there are modal anti-luck demands on both knowledge and justification, and it turns out that our beliefs about the moral status of our prospective actions are almost never able to satisfy these demands if objective act consequentialism is true. This kind of applied moral skepticism introduces problematic limits on our ability to use objective act consequentialism’s explanatory power as evidence for its truth. This is, in part, a product of higher-order defeat as I explain in the final section. There is, however, a silver lining for objective act consequentialists. For there is at least one type of objective act consequentialism, prior existence consequentialism, that is poised to avoid at least some of the epistemic problems discussed in this paper

Epistemic Non-Factualism and Methodology

I discuss methodology in epistemology. I argue that settling the facts, even the epistemic facts, fails to settle the questions of intellectual policy at the center of our epistemic lives. An upshot is that the standard methodology of analyzing concepts like knowledge, justification, rationality, and so on is misconceived. More generally, any epistemic method that seeks to issue in intellectual policy by settling the facts, whether by way of abductive theorizing or empirical investigation, no matter how reliable, is inapt. The argument is a radicalization of Moore’s Open Question Argument. I conclude by considering the ramifications of this conclusion for the debate surrounding “Modal Security”, a proposed necessary condition on undermining defeat

Normalcy, justification, and the easy-defeat problem

Recent years have seen the rise of a new family of non-probabilistic accounts of epistemic justification. According to these views—we may call them Normalcy Views—a belief in P is justified only if, given the evidence, there exists no normal world in which S falsely beliefs that P. This paper aims to raise some trouble for this new approach to justification by arguing that Normalcy Views, while initially attractive, give rise to problematic accounts of epistemic defeat. As we will see, on Normalcy Views seemingly insignificant pieces of evidence turn out to have considerable defeating powers. This problem—I will call it the Easy-Defeat Problem—gives rise to a two-pronged challenge. First, it shows that the Normalcy View has counterintuitive implications and, second, it opens the door to an uncomfortable skeptical threat.Publisher PDFPeer reviewe

Nearly cloaking the elastic wave fields

In this work, we develop a general mathematical framework on regularized approximate cloaking of elastic waves governed by the Lam\'e system via the approach of transformation elastodynamics. Our study is rather comprehensive. We first provide a rigorous justification of the transformation elastodynamics. Based on the blow-up-a-point construction, elastic material tensors for a perfect cloak are derived and shown to possess singularities. In order to avoid the singular structure, we propose to regularize the blow-up-a-point construction to be the blow-up-a-small-region construction. However, it is shown that without incorporating a suitable lossy layer, the regularized construction would fail due to resonant inclusions. In order to defeat the failure of the lossless construction, a properly designed lossy layer is introduced into the regularized cloaking construction . We derive sharp asymptotic estimates in assessing the cloaking performance. The proposed cloaking scheme is capable of nearly cloaking an arbitrary content with a high accuracy

Reasons Against Belief: A Theory of Epistemic Defeat

Despite its central role in our cognitive lives, rational belief revision has received relatively little attention from epistemologists. This dissertation begins to fill that absence. In particular, we explore the phenomenon of defeasible epistemic justification, i.e., justification that can be lost as well as gained by epistemic agents. We begin by considering extant theories of defeat, according to which defeaters are whatever cause a loss of justification or things that somehow neutralize one's reasons for belief. Both of these theories are both extensionally and explanatorily inadequate and, so, are rejected. We proceed to develop a novel theory of defeat according to which defeaters are reasons against belief. According to this theory, the dynamics of justification are explained by the competition between reasons for and reasons against belief. We find that this theory not only handles the counter-examples that felled the previous theories but also does a fair job in explaining the various aspects of the phenomenon of defeat. Furthermore, this theory accomplishes this without positing any novel entities or mechanisms; according to this theory, defeaters are epistemic reasons against belief, the mirror image of our epistemic reasons for belief, rather than sui generis entities