Abductive Replies to Skepticism

IBE ('Inference to the best explanation' or abduction) is a popular and highly plausible theory of how we should judge the evidence for claims of past events based on present evidence. It has been notably developed and supported recently by Meyer following Lipton. I believe this theory is essentially correct. This paper supports IBE from a probability perspective, and argues that the retrodictive probabilities involved in such inferences should be analysed in terms of predictive probabilities and a priori probability ratios (...) of initial events. The key point is to separate these two features. Disagreements over evidence can be traced to disagreements over either the a priori probability ratios or predictive conditional ratios. In many cases, in real science, judgements of the former are necessarily subjective. The principles of iterated evidence are also discussed. The Sceptic's position is criticised as ignoring iteration of evidence, and characteristically failing to adjust a priori probability ratios in response to empirical evidence. (shrink)

Dogmatism holds that an experience or seeming that p can provide prima facie immediate justification for believing p in virtue of its phenomenology. Dogmatism about perceptual justification has appealed primarily to proponents of representational theories of perceptual experience. Call dogmatism that takes perceptual experience to be representational "representational phenomenal dogmatism." As we show, phenomenal seemings play a crucial role in dogmatism of this kind. Despite its conventional appeal to representational theorists, dogmatism is not by definition committed to any particular view (...) of perceptual experience. Naive realists and disjunctivists who hold that perceptual experience is a perceptual relation of direct acquaintance can also endorse dogmatism. Indeed, we argue that they ought to do so. Otherwise, they cannot maintain that relationalism about perceptual experience has an epistemic advantage compared to the representational view. We then show that even if we grant that relationalism has this advantage, only dogmatism that takes perceptual experience to be representational can be extended to account for non-deductive inferential justification. As an account of the latter is required to avoid succumbing to skepticism, relationalism, we argue, does not have the epistemic advantage its defenders claim it has. (shrink)

One of the many notable virtues of Igor Douven's The Art of Abduction is that it is open access. Since a well-written chapter-by-chapter overview of the book is.

An important line of response to scepticism appeals to the best explanation. But anti-sceptics have not engaged much with work on explanation in the philosophy of science. I plan to investigate whether plausible assumptions about best explanations really do favour anti-scepticism. I will argue that there are ways of constructing sceptical hypotheses in which the assumptions do favour anti-scepticism, but the size of the support for anti-scepticism is small.

The “problem of memory” in epistemology is concerned with whether and how we could have knowledge, or at least justification, for trusting our apparent memories. I defend an inductive solution—more precisely, an abductive solution—to the problem. A natural worry is that any such solution would be circular, for it would have to depend on memory. I argue that belief in the reliability of memory can be justified from the armchair, without relying on memory. The justification is, roughly, that my having (...) the sort of experience that my apparent memory should lead me to expect is best explained by the hypothesis that my memories are reliable. My solution is inspired by Harrod’s (1942) inductive solution. Coburn (1960) argued that Harrod’s solution contains a fatal flaw. I show that my solution is not vulnerable to Coburn’s objection, and respond to a number of other, recent and likely objections. (shrink)

Phenomenal Conservatism (the view that an appearance that p gives one prima facie justification for believing that p) is a promising, and popular, internalist theory of epistemic justification. Despite its popularity, it faces numerous objections and challenges. For instance, epistemologists have argued that Phenomenal Conservatism is incompatible with Bayesianism, is afflicted by bootstrapping and cognitive penetration problems, does not guarantee that epistemic justification is a stable property, does not provide an account of defeat, and is not a complete theory of (...) epistemic justification. This book shows that Phenomenal Conservatism is actually immune to some of these problems, though not all of them. Accordingly, it explores the prospects of integrating Phenomenal Conservatism with Explanationism (the view that epistemic justification is a matter of explanatory relations between one’s evidence and propositions supported by that evidence). The resulting theory, Phenomenal Explanationism, has advantages over Phenomenal Conservatism and Explanationism taken on their own. Phenomenal Explanationism is a highly unified, comprehensive internalist theory of epistemic justification that delivers on the promises of Phenomenal Conservatism while avoiding its pitfalls. (shrink)

Many epistemological problems can be solved by the objective Bayesian view that there are rationality constraints on priors, that is, inductive probabilities. But attempts to work out these constraints have run into such serious problems that many have rejected objective Bayesianism altogether. I argue that the epistemologist should borrow the metaphysician’s concept of naturalness and assign higher priors to more natural hypotheses.

In this critical notice, I focus my attention on the chapters that deal with the explanationist response to skepticism.

Memory skepticism denies our memory beliefs could have any notable epistemic good. One route to memory skepticism is to challenge memory’s epistemic trustworthiness, that is, its functioning in a way necessary for it to provide epistemic justification. In this paper we develop and respond to this challenge. It could threaten memory in such a way that we altogether lack doxastic attitudes. If it threatens memory in this way, then the challenge is importantly self-defeating. If it does not threaten memory in (...) this way, then the challenge leaves a foundation for an inference to the best explanation response, one we articulate and support. (shrink)

_ Source: _Page Count 13 A promising response to the threat of external world skepticism involves arguing that our commonsense view of the world best explains the sensory experiences that we have. Since our commonsense view of the world best explains our evidence, we are justified in accepting this commonsense view of the world. Despite the plausibility of this Explanationist Response, it has recently come under attack. James Beebe has argued that only a version of the Explanationist Response that provides (...) an a priori justification of inference to the best explanation can hope to respond to two serious objections. Additionally, he has argued that providing such an a priori justification requires an acceptable account of a priori probability and that it is unclear whether such an account can be developed. In this paper I argue that Beebe fails to provide adequate support for either of these claims. (shrink)

I defend external world realism. I assume that the principle of inference to the best explanation is justified: roughly, a hypothesis that provides a better explanation of the total evidence is more probable than one that does not. I argue that the existence of a world of spatial objects provides a systematic explanation of the spatial contents of visual experience, and that it provides a better explanation than traditional skeptical hypotheses. This paper thus pursues the explanationist strategy of Laurence BonJour (...) and Jonathan Vogel. It is an improved, more compelling defense, for at least two reasons. First, the attention to spatial properties, and in particular to what I call perspectival projections, makes the explanatory power of the realist hypothesis much more vivid and concrete. Second, the argument preserves and elucidates much that seems correct in the explanationist arguments others have offered while avoiding significant problems and shortcomings. (shrink)

Over four decades, research and policy have created layers of understandings in the quest for "good" corporate governance. The corporate excesses of the 1970s sparked a search for market mechanisms and disclosure to empower shareholders. The UK-focused problems of the 1990s prompted board-centric, structural approaches, while the fall of Enron and many other companies in the early 2000s heightened emphasis on director independence and professionalism. With the financial crisis of 2007–09, however, came a turn in some policy approaches and in (...) academic literature seeking a different way forward. This paper explores those four phases and the discourse each develops and then links each to assumptions about accountability and cognition. After the financial crisis came pointers in policy and practice away from narrow, rationalist prescriptions and toward what the philosopher Stephen Toulmin calls "reasonableness". Acknowledging that heightens awareness of complexity and interdependence in corporate governance practice. The paper then articulates a research agenda concerning what "reasonably" good corporate governance might entail. (shrink)

A common response to radical skeptical challenges to our knowledge of the external world has been that there are explanatory reasons (e.g., simplicity, coherence, explanatory power, conservatism) for favoring commonsense explanations of our sensory experiences over skeptical explanations. Despite the degree of visibility this class of response has enjoyed, it has often been viewed with skepticism [sic] by the epistemological community because of concerns about the epistemic merits of explanatory reasoning. I argue that skeptical challenges that employ skeptical hypotheses presuppose (...) central explanationist tenets and that this fact should raise one’s estimation of the strength of explanationist responses to skepticism. (shrink)

Laurence BonJour and more recently James Beebe have argued that the best way to defend the claim that abduction or inference to the best explanation is epistemically justified is the rationalist view that it is justified a priori. However, rationalism about abduction faces a number of challenges. This chapter focuses on one particular, highly influential objection, that there is no interpretation of probability available which is compatible with rationalism about abduction. The rationalist who wants to maintain a strong connection between (...) epistemic justification and probability would do best to rely on a Keynesian interpretation of probability. However, the latter is vulnerable to Ramsey’s famous criticism that we do not seem to perceive or be aware of such probabilities. The chapter argues that Ramsey’s criticism is unsuccessful, and that there are good reasons to be optimistic about our ability to have access to probabilities relevant to abductive inference. (shrink)

_ Source: _Page Count 14 Jonathan Vogel has argued in support of an explanationist response to skepticism in several works. Central to this explanationist response is the fact that our non-skeptical view of the world is a better explanation of our experiences than its skeptical rivals. Despite the plausibility of this response to skepticism, it is not without its critics. Recently, Matthew Gifford has argued that Vogel’s response has problems on two fronts. First, Gifford argues that Vogel’s strategy for showing (...) that the rwh is a better explanation than its skeptical rivals fails. Second, he argues that if Vogel’s strategy does succeed, then it accomplishes too much—it removes skeptical doubts when it should not. I argue that Gifford is mistaken on both accounts. (shrink)

_ Source: _Page Count 14 Jonathan Vogel has argued in support of an explanationist response to skepticism in several works. Central to this explanationist response is the fact that our non-skeptical view of the world is a better explanation of our experiences than its skeptical rivals. Despite the plausibility of this response to skepticism, it is not without its critics. Recently, Matthew Gifford has argued that Vogel’s response has problems on two fronts. First, Gifford argues that Vogel’s strategy for showing (...) that the rwh is a better explanation than its skeptical rivals fails. Second, he argues that if Vogel’s strategy does succeed, then it accomplishes too much—it removes skeptical doubts when it should not. I argue that Gifford is mistaken on both accounts. (shrink)

_ Source: _Volume 6, Issue 1, pp 30 - 43 Jonathan Vogel has argued in support of an explanationist response to skepticism in several works. Central to this explanationist response is the fact that our non-skeptical view of the world is a better explanation of our experiences than its skeptical rivals. Despite the plausibility of this response to skepticism, it is not without its critics. Recently, Matthew Gifford has argued that Vogel’s response has problems on two fronts. First, Gifford argues (...) that Vogel’s strategy for showing that the RWH is a better explanation than its skeptical rivals fails. Second, he argues that if Vogel’s strategy does succeed, then it accomplishes too much—it removes skeptical doubts when it should not. I argue that Gifford is mistaken on both accounts. (shrink)

Most promising responses to skepticism fall into “Moorean” or “rationalist” camps. Mooreans believe that some apparently circular forms of reasoning allow us to have justification to believe that skeptical hypotheses are false. Rationalists believe that we have a priori justification to believe that skeptical hypotheses are false. It can seem that anti-skeptics are stuck choosing between fishy circular reasoning and mysterious a priori justification. I present a new difficulty for rationalism by focusing on skeptical scenarios wherein our faculties of a (...) priori reasoning are untrustworthy. In dealing with these scenarios, rationalists end up having to embrace the same sorts of circular reasoning that Mooreans use to deal with more familiar skeptical scenarios. As a result, there is no viable diagnosis of what's wrong with Moorean reasoning that does not also apply to rationalism: both anti-skeptical approaches are in the same boat when it comes to embracing circular reasoning. (shrink)

According to the explanationist, we can rely on inference to best explanation to justifiably believe familiar skeptical hypotheses are false. On this view, commonsense beliefs about the existence and character of familiar, medium-sized dry goods provides the best explanation of our evidence and so justifies our belief that we're not brains-in-vats. This explanationist approach seems prima facie plausible until we press the explanationist to tell us what the data is that we're trying to explain by appeal to our beliefs about (...) external objects and how we could have access to it. (shrink)

According to a (once) venerable tradition, our knowledge of the external world is crucially dependent on divine favor: our ability to obtain knowledge of the world around us is made possible by God’s having so ordered things. I argue that this view, despite its unpopularity among con­temporary philosophers, is supported by a certain inference to the best explanation: namely, it provides an effective way of reconciling two widely held beliefs that, on the assumption of naturalism, appear incompatible: (1) that knowledge (...) is incompatible with the kind of luck present in Gettier sce­narios and (2) that arguments for external world skepticism can be effectively rebutted by “shifting” them in the style of G. E. Moore. (shrink)

I focus on a key argument for global external world scepticism resting on the underdetermination thesis: the argument according to which we cannot know any proposition about our physical environment because sense evidence for it equally justifies some sceptical alternative (e.g. the Cartesian demon conjecture). I contend that the underdetermination argument can go through only if the controversial thesis that conceivability is per se a source of evidence for metaphysical possibility is true. I also suggest a reason to doubt that (...) conceivability is per se a source of evidence for metaphysical possibility, and thus to doubt the underdetermination argument. (shrink)

Some philosophers argue that we are justified in rejecting skepticism because it is explanatorily inferior to more commonsense hypotheses about the world. Focusing on the work of Jonathan Vogel, I show that this “abductivist” or “inference to the best explanation” response rests on an impoverished explanatory framework which ignores the explanatory gap between an object's having certain properties and its appearing to have those properties. Once this gap is appreciated, I argue, the abductivist strategy is defeated.

Die philosophische Skepsis bezweifelt argumentativ, dass Menschen über Wissen verfügen. Eine interessante und viel beachtete Reaktion auf diese Skepsis basiert auf dem semantischen Externalismus. Obwohl die antiskeptische Strategie des Externalismus im Laufe der Jahre entscheident verbessert wurde, krankt sie in den Augen vieler Philosophen immer noch an einer stark beschränkten Reichweite: Sie ist nur hinsichtlich ganz bestimmter Varianten skeptischer Argumentation erfolgreich – durch geschickte Modifikation des skeptischen Arguments ist der Skeptiker in der Lage, sein Argument gegen den externalistischen Angriff zu (...) immunisieren. In diesem Artikel gehe ich der Frage nach, ob die vom Externalismus erzwungene modifizierte Fassung des skeptischen Arguments anfälliger für antiskeptische Angriffe ist als die ursprüngliche Version. Drei Versuche, die vom Externalismus erzwungene Modifikation des skeptischen Arguments in antiskeptischer Hinsicht auszunutzen, werden diskutiert. Einer der Versuche erscheint zunächst viel versprechend, doch letztlich erweisen sich alle drei antiskeptischen Folgestrategien als unbefriedigend. (shrink)

In The Realm of Reason (2004), Christopher Peacocke develops a “generalized rationalism” concerning, among other things, what it is for someone to be “entitled”, or justified, in forming a given belief. In the course of his discussion, Peacocke offers two arguments to the best explanation that aim to undermine scepticism and establish a justification for our belief in the reliability of sense perception, respectively. If sound, these ambitious arguments would answer some of the oldest and most vexing epistemological problems. In (...) this paper I will evaluate these arguments, concluding that they are inconclusive at best. Despite offering some interestingly original arguments, Peacocke gives us no reason to think that scepticism is false, and that perception is generally reliable. (shrink)

Laurence BonJour, among others, has argued that inference to the best explanation allows us to reject skeptical hypotheses in favor of our common-sense view of the world. BonJour considers several skeptical hypotheses, specifically: our experiences arise by mere chance, uncaused; the simple hypothesis which states merely that our experiences are caused unveridically; and an elaborated hypothesis which explains in detail how our unveridical experiences are brought about. A central issue is whether the coherence of one’s experience makes that experience more (...) likely to be veridical. BonJour’s recent treatment of “analog” and “digital” skeptical hypotheses is also discussed. I argue that, although there are important lessons to be learned from BonJour’s writings, his use of inference to the best explanation against skepticism is unsuccessful.Keywords: BonJour; Explanation; Inference to the best explanation; Skepticism; Confirmation; Probability; Coherence; External world. (shrink)

Abductivists claim that explanatory considerations (e.g., simplicity, parsimony, explanatory breadth, etc.) favor belief in the external world over skeptical hypotheses involving evil demons and brains in vats. After showing how most versions of abductivism succumb fairly easily to obvious and fatal objections, I explain how rationalist versions of abductivism can avoid these difficulties. I then discuss the most pressing challenges facing abductivist appeals to the a priori and offer suggestions on how to overcome them.

This paper focuses on a combination of the antiskeptical strategies offered by semantic externalism and the inference to the best explanation. I argue that the most difficult problems of the two strategies can be solved, if the strategies are combined: The strategy offered by semantic externalism is successful against standard skeptical brain-in-a-vat arguments. But the strategy is ineffective, if the skeptical argument is referring to the recent-envatment scenario. However, by focusing on the scenario of recent envatment the most difficult problems (...) of the antiskeptical strategy posed by the inference to the best explanation can be solved. The most difficult problems with this strategy are: Why is an explanation of our experience offered by the skeptical hypothesis more complex than our standard explanation? Why is the more complex explanation less likely to be true? By focussing on the recent envatment hypothesis both questions can be answered satisfactorily. Therefore, the combination of semantic externalism and the inference to the best explanation yields a powerful antiskeptical argument. (shrink)

A central project of traditional epistemology is to address skeptical questions and concerns regarding the rationality or epistemic justification of our empirical beliefs, especially beliefs regarding the external world, with the aim of understanding what makes it possible for such beliefs to have or lack justification, and of determining how much justification we have. A prominent anti-skeptical view in the history of epistemology, a view I shall call classical foundationalism, can be distinguished from other more contemporary versions of foundationalism in (...) part on the basis of two central commitments: (i) the traditional methodological commitment to carry out the project of addressing skepticism “from the armchair,” i.e., on the basis of what can be determined by a posteriori deliverances of introspection and a priori use of reason and reflection, without relying on empirical or scientific research that presupposes the existence of any external world of material objects (including armchairs); and (ii) a substantive commitment to the doctrine of the given, understood roughly as the view that empirical beliefs ultimately depend for their justification on a direct or immediate awareness of reasons to think these beliefs true, reasons simply “given” to us in conscious experience. -/- There has been a recent resurgence of interest in classical or “old-fashioned” varieties of foundationalism, and the debate seems, in some ways, to be repeating itself. Critics object that these attempted resurrections of classical foundationalism are just attempts to square the same old circles.”They argue that there are decisive or clearly sufficient reasons to deny that such a view can be right, let alone that an adequate theory can be developed that is defensible in all its essential details. I think that these critics are either missing the point of the traditional project, misunderstanding classical foundationalism, or exaggerating the severity of the problems they raise. -/- I will show that a number of common arguments against classical foundationalism are not nearly as worrisome as their proponents think. In Chapter 2, I defend classical foundationalism against the Sellarsian dilemma, and provide prima facie support from examples for the availability of foundational empirical beliefs. I then discuss some recent classical foundationalist accounts of the justification of foundational beliefs, argue that these accounts are less than satisfactory, and develop an account of my own. In Chapter 3 I defend classical foundationalism, as a version of internalism, against Bergmann’s recent dilemma for internalism. Finally, in Chapter 4, I take up the issue of skepticism about the external world, and, in closing, the related issue of whether any beliefs about the external world can themselves be empirically foundational. (shrink)

The abductivist reply to skepticism is the view that commonsense explanations of the patterns and regularities that appear in our sensory experiences should be rationally preferred to skeptical explanations of those same patterns and regularities on the basis of explanatory considerations. In this article I critically examine Laurence BonJour’s rationalist version of the abductivist position. After explaining why BonJour’s account is more defensible than other versions of the view, I argue that the notion of probability he relies upon is deeply (...) problematic, that he incorporates an implausible double-standard concerning a priori and a posteriori justification, and that his view is vulnerable to skepticism about the a priori. I suggest that some of these problems are due to idiosyncratic commitments BonJour makes and that abductivists would be better off without them. I conclude with some suggestions about how to improve BonJour’s abductivist response to skepticism. (shrink)

The Matrix presents a version of an old philosophical fable: the brain in a vat. A disembodied brain is floating in a vat, inside a scientist’s laboratory. The scientist has arranged that the brain will be stimulated with the same sort of inputs that a normal embodied brain receives. To do this, the brain is connected to a giant computer simulation of a world. The simulation determines which inputs the brain receives. When the brain produces outputs, these are fed back (...) into the simulation. The internal state of the brain is just like that of a normal brain, despite the fact that it lacks a body. From the brain’s point of view, things seem very much as they seem to you and me. (shrink)

Michael Williams has frequently considered and rejected approaches to “our knowledge of the external world”that see it as the best explanation for certain features of experience.This paper examines the salience of his position to approaches such as Mackie’s that do not deny thepresentational directness of ordinary experience but do permit a gap between how things appear and how theyare that allows for sceptical doubts.Williams’ main argument is that, to do justice to its place in a foundationalist strategy, the external world (...) ashypothesis must offer an explicandum that does not invoke concepts of objects but is rather purely experiential.He next claims that no coherent regularities are available at such a level so there is nothing to be explained.Coherence only comes with objects, not as something objects could explain.Confronting this with Mackie’s Lockean theory of perception, we find that Mackie decisively rejects the firstclaim about the nature of the explicandum, since he sees ordinary perception as involving intentional objectswhich are distinct from the persisting objects they present. He is also committed to rejecting Williams’ line onpurely experiential regularities, though this plays a subordinate role in his general position.The crucial issue then becomes the tenability of Mackie’s intentional object analysis and the extent to which itmight yet tilt the argument in favour of realism against a global sceptic.In formulating his own epistemological strategies Williams might appear to countenance a version of Mackie’sview divorced from foundationalism. But while Williams’ contextualism in its minimal version might do so, inpractice it retains the lessons derived from his skirmishes with scepticism and thus disallows certain types ofenquiry.I conclude by contrasting Mackie’s response to scepticism with that of Williams in his diagnostic vein. (shrink)

This paper examines the role of ?situations? in John Dewey's philosophy of logic. To do this properly it is necessary to contrast Dewey's conception of experience and mentality with views characteristic of modern epistemology. The primary difference is that, rather than treat experience as peripheral and or external to mental functions (reason, etc.), we should treat experience as a field in and as a part of which thinking takes place. Experience in this broad sense subsumes theory and fact, hypothesis and (...) evidence, reason and observation, thought and perception. Logic in this view is a formal study of the generic features of all possible kinds of experience in this broad (thick, deep, wide, multifaceted) sense. The goal of this paper is to explain what Dewey thinks a situation is in the context of this view of experience, and to argue for the fundamental importance of that idea for logic and philosophy in general. (shrink)

Crispin Wright tried to refute classical 'Cartesian' skepticism contending that its core argument is extendible to a reductio ad absurdum (_Mind<D>, 100, 87-116, 1991). We show both that Wright is mistaken and that his mistakes are philosophically illuminating. Wright's 'best version' of skepticism turns on a concept of warranted belief. By his definition, many of our well-founded beliefs about the external world and mathematics would not be warranted. Wright's position worsens if we take 'warranted belief' to be implicitly defined by (...) the general principles governing it. Those principles are inconsistent, as shown by a variant of Godel's argument. Thus the inconsistency Wright found has nothing to do with the special premises of Cartesian skepticism, but is embedded in his own conceptual apparatus. Lastly, we show how a Cartesian skeptic could avoid Wright's critique by reconstructing a skeptical argument that does not use the claims Wright ultimately finds objectionable. (shrink)

The subject of this thesis is physicalism, understood not as some particular doctrine pertaining narrowly to the philosophy of mind, but rather as a quite general metaphysical claim to the effect that everything is, or is fundamentally, physical. Thus physicalism explicates the thought that in some sense physics is the basic science. The aim of the thesis is to defend a particular brand of physicalism, which I call eliminative type physicalism. It claims, roughly, that every property is a physical property, (...) a property mentioned in the laws of physics, and hence that any putative property not identifiable with a physical property must be eliminated from our ontology. Eliminative type physicalism is apt to face three objections, and so my thesis, like Caesar's Gaul, falls into three parts. In the first, I argue against the idea that there are tenable positions, both physicalist and non-physicalist, alternative to eliminative type physicalism. I argue that each of these positions token physicalism (Fodor, middle Putnam), supervenience physicalism (Lewis, Horgan) and and a non-physicalist view I call pluralism (Goodman, late Putnam) is defective. In the second part, responding to the objection that there is just no reason to be a physicalist, I develop a positive argument for eliminative type physicalism, an argument resting upon a strong version of the explanatory test for reality according to which only explanatorily indispensable properties can justifiably be said to exist. In the third and final part, I argue, against the charge that eliminative type physicalism cannot accommodate what I call phenomenal properties (qualia, raw feels etc.), that there is no good reason to deny, and one good reason to affirm, that phenomenal properties just are physical properties. (shrink)

In a recent article entitled “Scepticism and Knowing That One Knows”, Michael Hall poses a sceptical argument based upon two rules of inference:where ‘Kp’ stands for ‘it is known that p'. The argument goes:Hall attacks R2, but he says little about R1. I wish to add a few words of warning about R1 as well.

In this dissertation I consider the problem of external world skepticism and attempts at providing an argument to the best explanation against it. In chapter one I consider several different ways of formulating the crucial skeptical argument, settling on an argument that centers on the question of whether we're justified in believing propositions about the external world. I then consider and reject several options for getting around this issue which I take to be inadequate. I finally conclude that the best (...) option available to us at the moment is to argue that the antiskeptical view is the best explanation of our ordinary experiences In chapter two I argue that, if we hope to ground what counts as defending antiskepticism in common sense, there is an argument against the possibility of ever knowing one has succeeded in defending antiskepticism. After showing that common sense is no place to look in setting a goal for our antiskeptical project, I present the view that what will be crucial to settling on our antiskeptical goal is coming to a successful analysis of the nature of physical objects. I suggest some minimal criteria that must be met by a view in order to be antiskeptical based on our intuitions about core skeptical cases, but acknowledge that a fully successful response to external world skepticism will require the antiskeptic to engage in some much more difficult analysis. In chapter three I consider various views of the nature of explanation and conclude, tentatively, that explanation as it interests the antiskeptic is fundamentally causal. In chapter four I consider and reject some of the core views on which best explanation facts are so fundamental that a project of attempting to vindicate probabilistically the virtues which make explanations epistemically good. In this chapter I show that views which analyze justification in terms of best explanation factors fail. In chapter five I attempt to vindicate the various explanatory virtues probabilistically. In doing so I attempt to express or translate the various explanatory virtues in terms of probabilities in order to show that having those virtues makes a view at least prima facie more probable. In chapters six and seven I explain and evaluate the various arguments to the best explanation against skepticism present in current philosophical literature. I attempt to show that extant arguments fail to appreciate the virtues possessed by classical skeptical scenarios. In chapter eight I briefly consider some options that may be open to the antiskeptic moving forward. All routes forward contain considerable obstacles, but there are some fruitful areas of research to pursue. (shrink)