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. (shrink)

This paper does four things. First it lays out an orthodox position on reasons and defeaters. Then it argues that the position just laid out is mistaken about “undercutting” defeaters. Then the paper explains an unpublished thought experiment by Dorothy Edgington. And then it uses that thought experiment to motivate a new approach to undercutting defeaters.

In a recent article, Joel Pust argued that direct inference based on reference properties of differing arity are incommensurable, and so direct inference cannot be used to resolve the Sleeping Beauty problem. After discussing the defects of Pust's argument, I offer reasons for thinking that direct inferences based on reference properties of differing arity are commensurable, and that we should prefer direct inferences based on logically stronger reference properties, regardless of arity.

Philosophers disagree about the role of reflection for rationality, understood as the capacity to (properly) respond to genuine, normative reasons. Here, ‘reflection’ means the capacity for self-conscious normative meta-cognition. This article develops and rejects a novel argument – the argument from undercutting defeaters – in favor of the ‘one-level view’ that holds that having the concept of a belief (and of a reason) is necessary for responding to reasons. It will be argued that the ‘two-level view’, which allows for (...) rational subjects that can only non-reflectively respond to reasons, is supported by considerations dealing with the role of responding to reasons for rational action. Rationality is not as unified as the one-level view wants to have it. We start with the non-reflective way of rationally forming beliefs and then grow into the reflective way. (shrink)

My aim in this paper is to cast doubt on the idea of undercutting defeat by showing that it is beset by some serious problems. I examine a number of attempts to specify the conditions for undercutting defeat and find them to be defective. Absent further attempts, and on the basis of the considerations offered, I conclude that an adequate notion of undercutting defeat is lacking.

Evidence from biology and psychology suggests that our moral views depend on our evolutionary history. For example, if we humans would have evolved to live like hive bees, we would probably think very differently about moral questions such as whether we have a duty to care for our children. The findings from biology and psychology threaten to ‘debunk’ the justification of judgements about objective moral truths. Objective moral truths are always the same and they do not vary with our contingent (...) evolutionary history, whereas our moral judgements do. It has been argued that we, therefore, cannot tell right from wrong. In my thesis, I investigate the epistemology behind the evolutionary debunking of morality. Evolutionary explanations of morality, I argue, do not imply that our moral judgements are false. This leaves the possibility that evolution undercuts our (alleged) evidence for our moral judgements. Our evolutionarily influenced moral judgements might turn out to be unreliable guides to the moral truth, just like sight is a lousy guide to the external world in bad lighting conditions. However, I show that as long as we have reason to initially trust our moral beliefs, evolution does not provide us with reason to give up our moral beliefs. If evolution undercuts our moral beliefs, evolutionary considerations must show that true moral judgements do not qualify as knowledge because moral judgements are not cognitive achievements but comparable to lucky guesses. The thesis thus answers how empirical investigations of morality might have justificatory implications and the findings are relevant for deciding whether new factual information can alter how we think about right and wrong. (shrink)

Epistemic defeat is standardly understood in either evidentialist or responsibilist terms. The seminal treatment of defeat is an evidentialist one, due to John Pollock, who famously distinguishes between undercutting and rebutting defeaters. More recently, an orthogonal distinction due to Jennifer Lackey has become widely endorsed, between so-called doxastic (or psychological) and normative defeaters. We think that neither doxastic nor normative defeaters, as Lackey understands them, exist. Both of Lackey’s categories of defeat derive from implausible assumptions about (...) epistemic responsibility. Although Pollock’s evidentialist view is superior, the evidentialism per se can be purged from it, leaving a general structure of defeat that can be incorporated in a reliabilist theory that is neither evidentialist nor responsibilist in any way. (shrink)

I make a case for distinguishing clearly between subjective and objective accounts of undercutting defeat and for rejecting a hybrid view that takes both subjective and objective elements to be relevant for whether or not a belief is defeated. Moderate subjectivists claim that taking a belief to be defeated is sufficient for the belief to be defeated; subjectivist idealists add that if an idealised agent takes a belief to be defeated then the belief is defeated. Subjectivist idealism evades (...) some of the objections levelled against moderate subjectivism but can be shown to yield inconsistent results in some cases. Both subjectivisms should be rejected. We should be objectivists regarding undercutting defeat. This requirement, however, is likely to be problematic for a popular interpretation of evolutionary debunking arguments in metaethics as it can be shown that existing objectivist accounts of defeat do not support such arguments. I end by discussing the constraints of developing such an account. (shrink)

Justification depends on context: even if E on its own justifies H, still it might fail to justify in the context of D. This sort of effect, epistemologists think, is due to defeaters, which undermine or rebut a would-be justifier. I argue that there is another fundamental sort of contextual feature, disqualification, which doesn't involve rebuttal or undercutting, and which cannot be reduced to any notion of screening-off. A disqualifier makes some would-be justifier otiose, as direct testimony sometimes does (...) to distal testimony, and as manifestly decisive evidence might do to gratuitous evidence on the same team. Basing a belief on disqualified evidence, moreover, is distinctively irrational. One is not necessarily irresponsible. Instead one is turning down a free upgrade to a sleeker, stabler basis for one's beliefs. Such an upgrade would prevent wastes of epistemic effort, since someone who bases her belief on a disqualified proposition E will need to remember E and rethink her belief should E ever be defeated. The upgrade might also reduce reliance on unwieldy evidence, if E is relevant only thanks to some labyrinthine argument; and if even ideal agents should doubt their ability to follow such arguments, even they should care about disqualifiers. (shrink)

Scott Sturgeon has recently challenged Pollock’s account of undercutting defeaters. The challenge involves three primary contentions: the account is both too strong and too weak, undercutting defeaters exercise their power to defeat only in conjunction with higher-order beliefs about the basis of the lower-order beliefs whose justification they target, and since rebutting defeaters exercise their power to defeat in isolation, rebutting and undercutting defeaters work in fundamentally different ways. My goal is to reject each of (...) these contentions. I maintain that Sturgeon fails to show that Pollock’s account of undercutting defeaters is either too strong or too weak, his own account of how undercutting defeaters exercise their power to defeat is both too strong and too weak, and his claim that rebutting and undercutting defeaters work in fundamentally different ways is mistaken. (shrink)

Higher-order defeat occurs when one loses justification for one's beliefs as a result of receiving evidence that those beliefs resulted from a cognitive malfunction. Several philosophers have identified features of higher-order defeat that distinguish it from familiar types of defeat. If higher-order defeat has these features, they are data an account of rational belief must capture. In this article, I identify a new distinguishing feature of higher-order defeat, and I argue that on its own, and (...) in conjunction with the other distinguishing features, it favors an account of higher-order defeat grounded in non-evidential, ‘state-given reasons’ for belief. (shrink)

According to the phenomenal conservatives, beliefs are justified by non-doxastic states we might speak of as ‘appearances’ or ‘seemings’. Those who defend the view say that there is something self-defeating about believing that phenomenal conservatism is mistaken. They also claim that the view captures an important internalist insight about justification. I shall argue that phenomenal conservatism is indefensible. The considerations that seem to support the view commit the phenomenal conservatives to condoning morally abhorrent behavior. They can deny that their view (...) forces them to condone morally abhorrent behavior, but then they undercut the defenses of their own view. (shrink)

In my () I argued that a central component of mathematical practice is that published proofs must be “transferable” — that is, they must be such that the author's reasons for believing the conclusion are shared directly with the reader, rather than requiring the reader to essentially rely on testimony. The goal of this paper is to explain this requirement of transferability in terms of a more general norm on defeat in mathematical reasoning that I will call “convertibility”. I (...) begin by discussing two types of epistemic defeat: “rebutting” and “undercutting”. I give examples of both of these kinds of defeat from the history of mathematics. I then argue that an important requirement in mathematics is that published proofs be detailed enough to allow the conversion of rebutting defeat into undercutting defeat. Finally, I show how this sort of convertibility explains the requirement of transferability, and contributes to the way mathematics develops by the pattern referred to by Lakatos () as “lemma incorporation”. (shrink)

Evolutionary Debunking Arguments purport to show that our moral beliefs do not amount to knowledge because these beliefs are “debunked” by the fact that our moral beliefs are, in some way, the product of evolutionary forces. But there is a substantial gap in this argument between its main evolutionary premise and the skeptical conclusion. What is it, exactly, about the evolutionary origins of moral beliefs that would create problems for realist views in metaethics? I argue that evolutionary debunking arguments are (...) best understood as offering up defeaters for our moral beliefs. Moreover, the defeater in question is a paradigmatic instance of undercutting defeat. If anything is an undercutting defeater, then learning about the evolutionary origins of our moral beliefs is a defeater for those beliefs. (shrink)

There is widespread consensus that there are undercutting and rebutting defeaters that diminish or destroy the warrant of a belief B. I argue that there are counterparts of defeaters: the counterparts of undercutting defeaters are “requirement fulfillment beliefs”, the counterparts of rebutting defeaters are “consistency beliefs”. These beliefs confirm the warrant of B, I therefore call them “confirmers”.

Pre-natal genetic enhancement affords us unprecedented capacity to shape our skills, talents, appearance and perhaps subsequently the quality of our lives in terms of overall happiness, success and wellbeing. Despite its powerful appeal, some have raised important and equally persuasive concerns against genetic enhancement. Sandel has argued that compassion and humility, themselves grounded in the unpredictability of talents and skills, would be lost. Habermas has argued that genetically altered individuals will see their lives as dictated by their parents’ design and (...) therefore will not acquire an appropriate self-understanding. How should we view enhancement efforts in light of these concerns? I propose that we begin by adopting a defeasibility stance. That is, I ask whether our belief that genetic enhancements serve in the best interests of the child is reason to genetically enhance, underscoring a sort of epistemic vulnerability. I utilize the epistemological notions of defeasible reasons, undercutting and overriding defeaters in order to better understand and systematically evaluate the force of such concerns. I argue that close examination of both objections using this framework shows that we have reason to enhance, a reason that is defeasible but as yet, undefeated. (shrink)

Jonathan Kvanvig has argued that what he terms “doxastic” theories of epistemic justification fail to account for certain epistemic features having to do with evidence. I’m going to give an argument roughly along these lines, but I’m going to focus specifically on proper function theories of justification or warrant. In particular, I’ll focus on Michael Bergmann’s recent proper function account of justification, though the argument applies also to Alvin Plantinga’s proper function account of warrant. The epistemic features I’m concerned about (...) are experiences that should generate a believed defeater but don’t. I’ll argue that proper functionalism as it stands cannot account for the epistemic effects of these defeating experiences—or, at least, that it can only do so by embracing a deeply implausible view of our cognitive faculties. I’ll conclude by arguing that the only plausible option Bergmann has for modifying his theory undercuts the consideration that motivates proper functionalism in the first place. (shrink)

Two notions from philosophical logic and linguistics are brought together and applied to the psychological study of defeasible conditional reasoning. The distinction between disabling conditions and alternative causes is shown to be a special case of Pollock's (1987) distinction between ‘rebutting' and ‘undercutting' defeaters. ‘Inferential' conditionals are shown to come in two types, one that is sensitive to rebutters, the other to undercutters. It is thus predicted and demonstrated in two experiments that the type of inferential conditional used as (...) the major premise of conditional arguments can reverse the heretofore classic, distinctive effects of defeaters. (shrink)

Two notions from philosophical logic and linguistics are brought together and applied to the psychological study of defeasible conditional reasoning. The distinction between disabling conditions and alternative causes is shown to be a special case of Pollock’s (1987) distinction between ‘rebutting’ and ‘undercutting’ defeaters. ‘Inferential’ conditionals are shown to come in two varieties, one that is sensitive to rebutters, the other to undercutters. It is thus predicted and demonstrated in two experiments that the type of inferential conditional used as (...) the major premise of conditional arguments can reverse the heretofore classic, distinctive effects of defeaters. (shrink)

Two notions from philosophical logic and linguistics are brought together and applied to the psychological study of defeasible conditional reasoning. The distinction between disabling conditions and alternative causes is shown to be a special case of Pollock’s (1987) distinction between ‘rebutting’ and ‘undercutting’ defeaters. ‘Inferential’ conditionals are shown to come in two varieties, one that is sensitive to rebutters, the other to undercutters. It is thus predicted and demonstrated in two experiments that the type of inferential conditional used as (...) the major premise of conditional arguments can reverse the heretofore classic, distinctive effects of defeaters. (shrink)

In this paper, I present a solution to the problem that the need to accommodate the phenomenon of epistemic defeat poses for reliabilism. Defeaters are supposed to remove justification for previously justified beliefs. According to standard process reliabilism, the justification of a belief depends on the reliability of a process that is already completed when a defeater for that belief is obtained. It is hard to see, then, how a defeater can affect reliabilist justification, if that justification, from the (...) perspective of the defeater, lies wholly in the past. What is more, undercutting defeaters plausibly defeat by generating incompatibilities with higher-order propositions :105–118, 2014; Melis in Philos Stud 170:433–442, 2014). This is hard to integrate with reliabilism which explicitly denies higher-order conditions for justification. I argue that both of these phenomena can be accommodated by it via what I call the “Replacement Principle”: when a defeater is obtained, it generates either a logical incompatibility or a doxastic incompatibility. The resulting tension is registered and initiates a reasoning process that compares the epistemic support for the defeater with that for the defeated belief. This process may replace the original reliable formation process as a doxastic base for the defeated belief. If the defeater is not given its due weight in the reasoning process, that process was unreliable and if the defeated belief is retained as a result, it will be unjustified. This is intuitively the right result. Since reasoning is reliable, only if it is rational, the account manages to capture the intuition that disregarding a defeater would be irrational without having to make rationality a condition for justification. Replacement is not only plausible on causal pictures of doxastic basing, but also required in order to allow for the possibility of belief reevaluation in general and is therefore not an ad hoc addition to reliabilism, but rather part of its inherent explanatory resources. (shrink)

Two notions from philosophical logic and linguistics are brought together and applied to the psychological study of defeasible conditional reasoning. The distinction between disabling conditions and alternative causes is shown to be a special case of Pollock’s (1987) distinction between ‘rebutting’ and ‘undercutting’ defeaters. ‘Inferential’ conditionals are shown to come in two varieties, one that is sensitive to rebutters, the other to undercutters. It is thus predicted and demonstrated in two experiments that the type of inferential conditional used as (...) the major premise of conditional arguments can reverse the heretofore classic, distinctive effects of defeaters. (shrink)

Global meta-philosophical skepticism (i.e. completely unrestricted skepticism about philosophy) based upon disagreement faces the problem of self-defeat since it undercuts its motivating conciliatory principle. However, the skeptic may easily escape this threat by adopting a more modest kind of skepticism, that will be called “extensive meta-philosophical skepticism”, i.e., the view that most of our philosophical beliefs are unjustified, except our beliefs in epistemically fundamental principles. As I will argue in this paper, this kind of skepticism is well-motivated, does not (...) undercut the conciliatory principle, but still poses a radical challenge to philosophy as a cognitive discipline. Moreover, I will argue that non-global skepticism that is still extensive undermines itself as well. The deeper reason for this is that this more modest kind of skepticism can only be motivated by the assumption that disagreement with philosophical peers is abundant and that we can identify peers only by relying on track-record arguments. But then one can argue for extensive meta-philosophical skepticism only if one presupposes that those philosophical beliefs that form the basis of track-record evaluations are justified. Here, the threat of self-defeat looms again. I will proceed by first defending the premises of this new anti-skeptical argument against standard objections from the literature. Second, I will show in more detail where the epistemic inconsistency arises in the argument for extensive meta-philosophical skepticism. I conclude with an assessment of the scope and the limits of my argument. (shrink)

In this chapter, we begin by sketching in the broadest possible strokes the ideas behind two formal systems that have been introduced with to goal of explicating the ways in which reasons interact to support the actions and conclusions they do. The first of these is the theory of defeasible reasoning developed in the seminal work of Pollock; the second is a more recent theory due to Horty, which adapts and develops the default logic introduced by Reiter to provide an (...) account of reasons. However, the implementations are complex enough, in both cases, to prevent anything more than this sketch. And we would not want to give the impression that we think that work on the logic of reasons must follow the path mapped out in either of these theories—indeed, we feel that the field is wide open. In the remainder of the chapter, therefore, will concentrate on a number of issues bearing on the logic of reasons that are either not treated in the work of Pollock and Horty, or whose treatment there is, we feel, either inadequate or incomplete. These are: first, the question of whether it is necessary to understand logical interactions among reasons themselves, rather than simply between reasons and the actions or conclusions they support, and if so, what principles might govern these interactions; second, priority relations among reasons and the notion of reason accrual; and third, some problems posed by undercutting defeat. (shrink)

On explanationist accounts of genealogical debunking, roughly, a belief is debunked when its explanation is not suitably related to its content. We argue that explanationism cannot accommodate cases in which beliefs are explained by factors unrelated to their contents but are nonetheless independently justified. Justification-specific versions of explanationism face an iteration of the problem. The best account of debunking is a probabilistic account according to which subject S’s justification J for their belief that P is debunked when S learns that (...) J is no more likely to be true on the hypothesis that P than on the hypothesis that ¬P. The probabilistic criterion is fully general, applying not only to cases where the learned undercutting defeater is a proposition about our beliefs or other mental states but to any case of undercutting defeat, providing the grounds for a debunking argument against the existence of a special, metacognitive debunking principle. (shrink)

In philosophy, as in many other disciplines and domains, stable disagreement among peers is a widespread and well-known phenomenon. Our intuitions about paradigm cases, e.g. Christensen's Restaurant Case, suggest that in such controversies suspension of judgment is rationally required. This would prima facie suggest a robust suspension of judgment in philosophy. But we are still lacking a deeper theoretical explanation of why and under what conditions suspension is rationally mandatory. In the first part of this paper I will focus on (...) this question. After a critical survey of some recent alternative approaches (diversity as a thread to the reliability, decision problem, acquisition of undercutting defeaters), I will argue that in fact discovering disagreement with an opponent provides me with a rebutting defeater, but only if some further non-trivial conditions are satisfied - among them my acknowledging her as my reliability peer. In the second part of the paper I will explore in more detail the skeptical implications this account has for philosophy. Here, I will defend two claims. First, skepticism about philosophy is mandatory only if the relevant peerness assumption can be justified. Second, in philosophy there is no basis available that would support the relevant peerness assumption. If this is correct, we are not forced into skepticism about philosophy and may rationally retain our philosophical beliefs even in the face of controversy. (shrink)

In the standard thought experiments, dualism strikes many philosophers as true, including many non-dualists. This ‘striking’ generates prima facie justification: in the absence of defeaters, we ought to believe that things are as they seem to be, i.e. we ought to be dualists. In this paper, I examine several proposed undercutting defeaters for our dualist intuitions. I argue that each proposal fails, since each rests on a false assumption, or requires empirical evidence that it lacks, or overgenerates defeaters. By (...) the end, our prima facie justification for dualism remains undefeated. I close with one objection concerning the dialectical role of rebutting defeaters, and I argue that the prospects for a successful rebutting defeater for our dualist intuitions are dim. Since dualism emerges undefeated, we ought to believe it. (shrink)

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)

Exclusionary defeat is Joseph Raz’s proposal for understanding the more complex, layered structure of practical reasoning. Exclusionary reasons are widely appealed to in legal theory and consistently arise in many other areas of philosophy. They have also been subject to a variety of challenges. I propose a new account of exclusionary reasons based on their justificatory role, rejecting Raz’s motivational account and especially contrasting exclusion with undercutting defeat. I explain the appeal and coherence of exclusionary reasons by (...) appeal to commonsense value pluralism and the intermediate space of public policies, social roles, and organizations. We often want our choices to have a certain character or instantiate a certain value and in order to do so, that choice can only be based on a restricted set of reasons. Exclusion explains how pro tanto practical reasons can be disqualified from counting towards a choice of a particular kind without being outweighed or undercut. (shrink)

Users of sociotechnical systems often have no way to independently verify whether the system output which they use to make decisions is correct; they are epistemically dependent on the system. We argue that this leads to problems when the system is wrong, namely to bad decisions and violations of the norm of practical reasoning. To prevent this from occurring we suggest the implementation of defeaters: information that a system is unreliable in a specific case (undercutting defeat) or independent (...) information that the output is wrong (rebutting defeat). Practically, we suggest to design defeaters based on the different ways in which a system might produce erroneous outputs, and analyse this suggestion with a case study of the risk classification algorithm used by the Dutch tax agency. (shrink)

An abstract framework for structured arguments is presented, which instantiates Dung's ('On the Acceptability of Arguments and its Fundamental Role in Nonmonotonic Reasoning, Logic Programming, and n- Person Games', Artificial Intelligence , 77, 321-357) abstract argumentation frameworks. Arguments are defined as inference trees formed by applying two kinds of inference rules: strict and defeasible rules. This naturally leads to three ways of attacking an argument: attacking a premise, attacking a conclusion and attacking an inference. To resolve such attacks, preferences may (...) be used, which leads to three corresponding kinds of defeat: undermining, rebutting and undercutting defeats. The nature of the inference rules, the structure of the logical language on which they operate and the origin of the preferences are, apart from some basic assumptions, left unspecified. The resulting framework integrates work of Pollock, Vreeswijk and others on the structure of arguments and the nature of defeat and extends it in several respects. Various rationality postulates are proved to be satisfied by the framework, and several existing approaches are proved to be a special case of the framework, including assumption-based argumentation and DefLog. (shrink)

The externalist says that your evidence could fail to tell you what evidence you do or not do have. In that case, it could be rational for you to be uncertain about what your evidence is. This is a kind of uncertainty which orthodox Bayesian epistemology has difficulty modeling. For, if externalism is correct, then the orthodox Bayesian learning norms of conditionalization and reflection are inconsistent with each other. I recommend that an externalist Bayesian reject conditionalization. In its stead, I (...) provide a new theory of rational learning for the externalist. I defend this theory by arguing that its advice will be followed by anyone whose learning dispositions maximize expected accuracy. I then explore some of this theory’s consequences for the rationality of epistemic akrasia, peer disagreement, undercutting defeat, and uncertain evidence. (shrink)

Christian apologists argue that the testimony of the miracles of Jesus provide evidence for Christianity. Hume tries to undermine this argument by pointing out that miracles are said to occur in other religious traditions and so miracles do not give us reason to believe in Christianity over the alternatives. Thus, competing miracles act as an undercutting defeater for the argument from miracles for Christianity. Yet, before Hume, Locke responds to this kind of objection, and in this paper I explain (...) and defend his response. In short, Locke argues that God will ensure that there is more evidence for Christianity (if true) and this greater evidence is an undercutting defeater for Hume’s competing miracles defeater (i.e., it is a defeater-defeater). If so, then, as Locke argues, competing miracles do not weaken the evidence from miracles for Christianity. (shrink)

The goal of this paper is to frame a theory of reasons--what they are, how they support actions or conclusions--using the tools of default logic. After sketching the basic account of reasons as provided by defaults, I show how it can be elaborated to deal with two more complicated issues: first, situations in which the priority relation among defaults, and so reasons as well, is itself established through default reasoning; second, the treatment of undercutting defeat and exclusionary reasons. (...) Finally, and by way of application, I show how the resulting account can shed some light on Jonathan Dancy's argument from reason holism to a form of extreme particularism in moral theory. (shrink)

James Henry Collin recently developed a new symmetry breaker favouring the ontological argument’s possibility premiss over that of the reverse ontological argument. The symmetry breaker amounts to an undercutting defeater for the reverse possibility premiss based on Kripkean cases of a posteriori necessity. I argue, however, that symmetry re-arises in two forms. First, I challenge the purported asymmetry in epistemic entitlements to the original and reverse possibility premisses. Second, relevantly similar Kripkean cases equally undercut the original possibility premiss.

Given plausible assumptions about the nature of evidence and undercutting defeat, many believe that the force of the evidential problem of evil depends on sceptical theism’s being false: if evil is...

This chapter argues that materialism is vulnerable to two kinds of epistemological objections: transcendental arguments, that show that materialism is incompatible with the very possibility of knowledge; and defeater arguments, that show that belief in materialism provides an effective defeaters to claims to knowledge. It constructs objections of these two kinds in three areas of epistemology: our knowledge of the laws of nature (and of scientific essences), our knowledge of the ontology of material objects, mathematical and logical knowledge. The chapter (...) argues that these epistemological weaknesses place the materialist in a dialectically weak position in respect of ontological identity claims, since the materialist cannot know the causal powers or persistence conditions of material objects. It also argues that the materialist can provide no non-circular account of epistemic normativity. Anti-realist accounts of normativity are unavailable because normativity is already implicated in all intentionality. Moreover, materialists face a fatal dilemma in attempting to carry out an etiological reduction of teleological norms, since neither Humean nor anti-Humean accounts of causation yield defensible results. (shrink)

Weisberg ([2009]) provides an argument that neither conditionalization nor Jeffrey conditionalization is capable of accommodating the holist’s claim that beliefs acquired directly from experience can suffer undercutting defeat. I diagnose this failure as stemming from the fact that neither conditionalization nor Jeffrey conditionalization give any advice about how to rationally respond to theory-dependent evidence, and I propose a novel updating procedure that does tell us how to respond to evidence like this. This holistic updating rule yields conditionalization as (...) a special case in which our evidence is entirely theory independent. 1 Introduction2 Conditionalization3 Holism and Conditionalization4 A Holistic Update5 HCondi and Dutch Books6 Commutativity and Learning about Background Theories6.1 Commutativity6.2 Learning about background theories7 In Summation. (shrink)

The “Embryo Rescue Case” (ERC) refers to a thought experiment that is used to argue against the view that embryos have a right to life (i.e. are persons). I will argue that cognitive science undermines the intuition elicited by the ERC; I will show that whether or not embryos have a right to life, our mental tools will make it very difficult to believe that embryos have said right. This suggests that the intuition elicited by the ERC is not truth (...) indicative. The upshot of this is that we have an undercutting defeater for our intuition that embryos do not have a right to life. (shrink)

Skeptical theism is the view that human knowledge and understanding are severely limited, compared to that of the divine. The view is deployed as an undercutting defeater for evidential arguments from evil. However, skeptical theism has broader skeptical consequences than those for the argument from evil. The epistemic principles of this skeptical creep are identified and shown to be on the road to global skepticism.

Although the study of reasons plays an important role in both epistemology and moral philosophy, little attention has been devoted to the question of how, exactly, reasons interact to support the actions or conclusions they do. In this book, John F. Horty attempts to answer this question by providing a precise, concrete account of reasons and their interaction, based on the logic of default reasoning. The book begins with an intuitive, accessible introduction to default logic itself, and then argues that (...) this logic can be adapted to serve as a foundation for a concrete theory of reasons. Horty then shows that the resulting theory helps to explain how the interplay among reasons can determine what we ought to do by developing two different deontic logics, capturing two different intuitions about moral conflicts.In the central part of the book, Horty elaborates the basic theory to account for reasoning about the strength of our own reasons, and also about the related concepts of undercutting defeaters and exclusionary reasons. The theory is illustrated with an application to particularist arguments concerning the role of principles in moral theory. The book concludes by introducing a pair of issues new to the philosophical literature: the problem of determining the epistemic status of conclusions supported by separate but conflicting reasons, and the problem of drawing conclusions from sets of reasons that can vary arbitrarily in strength, or importance. (shrink)

This paper considers how the terms ‘objection,’ ‘rebuttal,’ ‘attack,’ ‘refutation,’ ‘rebutting defeater’ and ‘undercutting defeater’ are used in writings on argumentation and artificial intelligence. The central focus is on the term ‘rebuttal.’ A provisional classification system is proposed that provides a normative structure within which the terms can be clarified, distinguished from each other, and more precisely defined.

I offer a new, limited solution to divine hiddenness based on a particular epistemic paradox: sometimes, knowing about a desired outcome or relevant features of that desired outcome would prevent the outcome in question from occurring. I call these cases epistemically self-defeating situations. This solution, in essence, says that divine hiddenness or silence is a necessary feature of at least some morally excellent or desirable states of affairs. Given the nature of the paradox, an omniscient being cannot completely eliminate hiddenness, (...) just as an omnipotent being cannot create a rock so heavy that they cannot lift it. Epistemically self-defeating situations provide an undercutting defeater for the assumption that any nonresistant nonbeliever could always, at any time, be in conscious relationship with a perfectly loving God. Thankfully, silence is a temporary feature of epistemically self-defeating situations: once the outcome is achieved, agents can know in full. (shrink)

The article considers two different interpretations of the reason model of precedent pioneered by John Horty. On a plausible interpretation of the reason model, past cases provide reasons to prioritize reasons favouring the same outcome as a past case over reasons favouring the opposing outcome. Here I consider the merits of this approach to the role of precedent in legal reasoning in comparison with a closely related view favoured by some legal theorists, according to which past cases provide reasons for (...) undercutting (or ‘excluding’) reasons favouring the opposing outcome. After embedding both accounts within a general default logic, I note some important differences between the two approaches that emerge as a result of plausible distinctions between rebutting and undercutting defeat in formal models of legal reasoning. These differences stem from the ‘preference independence’ of undercutting defeat. Undercutting reasons succeed in defeating opposing reasons irrespective of their relative strength. As a result, the two accounts differ in their account of the way in which precedents constrain judicial reasoning. I conclude by suggesting that the two approaches can be integrated within a single model, in which the distinction between undercutting and rebutting defeat is used to account for the distinction between strict and persuasive forms of precedential constraint. (shrink)

Joshua Matthan Brown contrasts the concept of God assumed by most analytic philosophers, what he refers to as theistic personalism, with that of the apophatic conception of God endorsed by Eastern Christian thinkers. He maintains that the most powerful and economical response to contemporary arguments for atheism is to reject theistic personalism and adopt apophatic theism. Apophatic theists believe there is a lot we cannot say about God, taking the divine nature to be completely ineffable. Brown develops a coherent account (...) of divine ineffability and provides reasons for adopting this oft misunderstood view. Importantly, he draws upon apophatic theology, and its commitment to divine ineffability, to proffer an undercutting defeater for virtually every contemporary argument for the nonexistence of God. Along the way he anticipates and responds to several significant objections. (shrink)

Although owing to proper basicality, phenomenal conservatism, and deliberative indispensability our axiomatic moral judgments seem to be prima facie justified, the question of potential undercutting defeaters can pose a challenge to moral knowledge. Evolutionary debunking arguments of various stripes are one of the more recent widely discussed contenders for such a defeater. Because of the likes of Michael Ruse, Richard Joyce, and Sharon Street, such arguments have attracted much attention. Their general structure features an empirical premise according to which (...) the process of evolution has had a significant impact on the stock of even our axiomatic moral judgments. The epistemic premise has it that if the empirical premise holds, then our moral knowledge is severely challenged if not debunked altogether, and perhaps even moral realism itself, since if our epistemic faculties can’t reliably put us in touch with objective moral truths, those truths are out of a job in our ontology. Since the most outspoken evolutionary debunkers are secularists, they somewhat understandably tend to smuggle something of a naturalistic origins thesis into their conception of evolution, thus precluding a divine guidance of the evolutionary process, which renders it a formidable challenge for them to evade the force of the debunking challenge. Unsurprisingly Ruse, Joyce, and Street all end up abandoning moral realism and any moral knowledge predicated on it. Theism, however, potentially provides a defeater-defeater against the evolutionary debunking argument(s) (if not a defeater-deflector), by rejecting the naturalistic origins thesis as a gratuitous theological add-on to which evolution need not be attached, carving out room for evolution to be a divinely guided process that may well ensure a correspondence between moral truth and at least our most nonnegotiable moral convictions. (shrink)

Collin (2022) attempts to break the symmetry between the modal ontological argument for the existence of God and the reverse modal ontological argument against the existence of God by drawing on some Kripkean lessons about a posteriori necessity. He argues that there is an undercutting defeater for taking God’s non-existence to be possible. In this paper, I reply that taking the Kripkean considerations about a posteriori necessity into account does not help break the symmetry. For we can argue in (...) a similar way that there is an undercutting defeater for taking God’s existence to be possible. (shrink)