Brains in Vats

This paper challenges Sosa’s account of the epistemic propriety of suspension of judgment. We take the reader on a test drive through some common problem cases in epistemology, to see how the account of suspension deals with them. Section 1 outlines Sosa’s account of accurate and apt suspension. Sections 2 and 3 focus on the skeptical scenario to argue that Sosa makes it too easy for suspension to be accurate and apt. Section 4 applies Sosa’s account of accurate and apt (...) suspension to BonJour’s case of Norman the clairvoyant. The upshot is that Sosa makes accurate and apt suspension not only too easy but also too hard. (shrink)

In everyday life, we often understand skepticism as a position that one may set aside because of its absurdity or incoherence. In Greek philosophy, skepticism was rather an inquiring attitude that led to the suspension of judgment and, as a result, the freedom from distress. In Modern philosophy, many philosophers viewed skepticism as a phase of thought that had to be overcome before laying firm foundations for the sciences. These pictures differ from the outlook that dominates current analytic epistemology, where (...) skepticism has normally been understood as a series of paradoxes that arise when we reflect on the workings of ordinary epistemic concepts like KNOWLEDGE and EPISTEMIC JUSTIFICATION. A skeptical paradox emerges when we identify a condition that seems to be necessary to have knowledge or epistemic justification, while it also seems that that condition cannot be met. This chapter explains why the picture of skepticism as a series of paradoxes is central to contemporary analytic epistemology and identifies some of the main features of skeptical paradoxes about the external world. After identifying two types of replies, it presents two influential paradoxes based on the closure and underdetermination principles, identifies some relevant differences between the two paradoxes, and critically examines some attempts at solving them. (shrink)

The Illusion of Doubt shows that radical scepticism is an illusion generated by a Cartesian picture of our evidential situation—the view that my epistemic grounds in both the ‘good’ and the ‘bad’ cases must be the same. It is this picture which issues both a standing invitation to radical scepticism and ensures that there is no way of getting out of it while agreeing to the sceptic’s terms. The sceptical problem cannot, therefore, be answered ‘directly’. Rather, the assumptions that give (...) rise to it, need to be undermined. These include the notion that radical scepticism can be motivated by the ‘closure’ principle for knowledge, that the ‘Indistinguishability Argument’ renders the Cartesian conception compulsory, that the ‘New Evil Genius Thesis’ is coherent, and the demand for a ‘global validation’ of our epistemic practices makes sense. Once these dogmas are undermined, the path is clear for a ‘realism without empiricism’ that allows us to re-establish unmediated contact with the objects and persons in our environment which an illusion of doubt had threatened to put forever beyond our cognitive grasp. (shrink)

Cartesian skepticism requires scenarios of massive deception to make its case. The inability to rule out such possibilities in which our beliefs about the external world are massively mistaken motivates the conclusion that we lack everyday knowledge. Some authors have emphasized that such scenarios are implausible. Others have instead claimed that scenarios are irrelevant to skepticism. If skepticism can make its case, they argue that scenarios of massive deception are not the way to do it. This thesis possesses a distinct (...) anti-sceptical weight. Deprived of its scenario, epistemological skepticism must find a different reason for it to be taken seriously, which might be a tall order. This paper defends the idea that scenarios do not constitute the essential element of the skeptical threat. However, it takes this result in the opposite direction. We aim to show that skepticism without scenarios constitutes a bigger and more legitimate philosophical problem than otherwise. Additionally, it also offers the possibility of achieving a unified understanding of skepticism that is so far lacking in contemporary epistemology, allowing us to better understand what can constitute a satisfactory anti-skeptical strategy. (shrink)

According to the simulation hypothesis, the world we live in is a computer simulation. According to longtermism, we should aim to bring about the best possible future. In this paper, I argue that there is a tension between the two: insofar as we have reason to think we are living in a computer simulation, we have reason to think the longtermist project will fail (or has already failed). I make my case by developing a novel version of the problem of (...) evil. It says that there exist certain forms of evil in our world that longtermist philosophers have argued we should try to eradicate. But then, the existence of those evils give us reason to think our world is not a computer simulation run by a being aligned with longtermist values. In short, the more that longtermists think we could make the world a better place in the future, the more troubling they should find it that the world is not already a better place, given the assumption that we are living in a computer simulation. (shrink)

This article gives a Bayesian argument showing that, even if your total empirical evidence confirms that you have zillions of duplicate Boltzmann Brains, that evidence does not confirm that you are a Boltzmann Brain. The article also attempts to explain what goes wrong with several of the sources of the temptation for thinking that such evidence does have skeptical implications.

According to veridicalism, your beliefs about the existence of ordinary objects are typically true, and can constitute knowledge, even if you are in some global sceptical scenario. Even if you are a victim of Descartes’ demon, you can still know that there are tables, for example. Accordingly, even if you don’t know whether you are in some such scenario, you still know that there are tables. This refutes the standard sceptical argument. But does it solve the sceptical problem posed by (...) that argument? I argue that it does not, because we do not know substantively more about the external world according to veridicalism than we do according to the sceptical argument. Rather, veridicalism merely reformulates what little knowledge we have. I then draw some general conclusions about the nature of the sceptical problem, the formulation of the standard argument, and the significance of this for some other, non-veridicalist strategies. (shrink)

Many philosophers have been attracted to a restricted version of the principle of indifference in the case of self‐locating belief. Roughly speaking, this principle states that, within any given possible world, one should be indifferent between different hypotheses concerning who one is within that possible world, so long as those hypotheses are compatible with one's evidence. My first goal is to defend a more precise version of this principle. After responding to several existing criticisms of such a principle, I argue (...) that existing formulations of the principle are crucially ambiguous, and I go on to defend a particular disambiguation of the principle. According to the disambiguation I defend, how we should apply this restricted principle of indifference sensitively depends on our background metaphysical beliefs. My second goal is to apply this disambiguated principle to classical skeptical problems in epistemology. In particular, I argue that Eternalism threatens to lead us to external world skepticism, and Modal Realism threatens to lead us to inductive skepticism. (shrink)

Verschwörungstheorien (VTn) sind in der erkenntnistheoretischen Literatur wiederholt mit skeptischen Hypothesen verglichen worden: Beide entzögen sich der empirischen Überprüfung, indem sie sich gegen Gegenbelege immunisierten. Im Falle von VTn bestehe die Immunisierung darin, dass vermeintliche Gegenbelege ungeprüft auf Vertuschungs- oder Täuschungshandlungen der Verschwörer zurückgeführt würden. Eine genauere Rekonstruktion der Täuschungsthese und ein genauerer Blick auf die Immunisierungsthese fördern aber eine Reihe von Disanalogien zutage: Im Unterschied zu skeptischen Hypothesen behaupten VTn das eigene Szenario als real und schreiben die Täuschung nur (...) der Fremdgruppe zu. Damit besteht bei VTn auch nicht die für skeptische Hypothesen typische Symmetrie der Beleglage: Keine Partei diagnostiziert ein Patt, jede weist vielmehr die angeführten Belege der Gegenseite zurück. VTn entziehen die Täuschungsthese auch nicht jeder möglichen Überprüfung, wie es das Szenario des bösen Dämons tut, sondern kommen in unterschiedlichen Graden der Selbstimmunisierung vor. Die epistemischen Defizite von VTn und die Untugenden ihrer Verfechter treten deutlicher hervor, wenn man den Fokus von der Verschwörungsthese auf die Dynamik ihrer Verteidigung und ihre Ähnlichkeiten zu degenerierenden Forschungsprogrammen verschiebt. -/- In the epistemological literature, conspiracy theories (CTs) are often compared with skeptical hypotheses: Both are said to resist empirical refutation by immunising themselves against counterevidence. In the case of CTs, the trick is to explain away alleged counterevidence by cover-ups or deceptive acts on the part of the conspirators. However, a more precise reconstruction of the deception thesis and a closer look at the immunization thesis reveal a number of disanalogies: Unlike skeptical hypotheses, CTs claim their own scenario to be real, while attributing deception only to the outgroup. Correspondingly, CTs do not exhibit the balance of evidence typical of skeptical hypotheses: Neither party considers the evidence to be symmetrical, each rejects the evidence adduced by the opposing party. Unlike the evil demon scenario, the deception thesis in CTs is not entirely uncheckable. Rather, different CTs exhibit varying degrees of self-immunisation. The epistemic deficiencies of CTs and the epistemic vices of their proponents can be better brought out by shifting the focus from a CT’s claim to the dynamics of defending it and the similarities to degenerating research programmes. (shrink)

One interesting and potentially attractive feature of the sensitivity account of knowledge is that it not only preserves knowledge of ordinary propositions, but also concedes the skeptic's intuition that we do not know skeptical hypotheses do not obtain. This paper challenges the sensitivity‐based reply to the skeptic, advocated by Robert Nozick, among others. Sensitivity generates an implausibly bizarre result that although we do not know we are not brains in vats (because a belief to this effect is insensitive), a real (...) BIV who is in a much worse epistemic situation can sensitively believe that it is not in the good case. This result reveals a fundamental problem with the sensitivity conditional: its antecedent is not suitable for picking out possibilities that are relevant for our epistemic evaluation. I then offer a systematic explanation of why it is the safety account—the main competitor of sensitivity—that picks out a more suitable set of possibilities. A consequence of this comparison is that the safety account delivers an overall more satisfying reply to the skeptic than sensitivity does. (shrink)

In this paper, I argue that the ecological approach to perception provides resources to overcome the causal argument against disjunctivism. According to the causal argument, since the brain states that proximally cause the perceptual experience and the corresponding hallucinatory one can be of the same type, there would be no good reason to reject that the perceptual experience and the corresponding hallucinatory experience have fundamentally the same nature. Disjunctivism concerning the nature of the experience would then be false. I identify (...) three assumptions that support the causal argument: the indistinguishability assumption, the linearity assumption, and the duplication assumption. According to the ecological approach to disjunctivism, these assumptions should be rejected, opening up room for a version of disjunctivism that I call 'Ecological Disjunctivism'. Perceptual episodes are extended over time and are supervenient to the organism-environment system. They can be distinguished from the 'corresponding' hallucinations because the former results from a controlled process of attunement to the environment, whereas hallucinations are passive and insensible to the exploratory activities of the perceptual system. Finally, ecological disjunctivism, since it is immune to the causal argument, is more advantageous than negative and positive disjunctivism. (shrink)

According to MODERATISM, perceptual justification requires that one independently takes for granted propositional hinges like <There is an external world>, <I am not a brain in a vat (BIV)>, and so on. This view faces the truth problem: to offer an account of truth for hinges that is not threatened by skepticism. Annalisa Coliva has tried to solve the truth problem by combining the claim that external world propositions have a substantive truth property like correspondence with the claim that hinges (...) have a deflationary truth property. I argue that the resulting view cannot offer a coherent characterization of ‘skeptical switch scenarios’ while providing an effective anti-skeptical strategy. In a more positive vein, I defend an approach that combines a correspondence conception of truth with epistemological disjunctivism. (shrink)

This is a critical notice of Christos Kyriacou and Kevin Wallbridge (eds.), Skeptical Invariantism Reconsidered. New York and London: Routledge, 2021. Pp. x + 324. ISBN 978-0-367-37018-3. It discusses in some detail contributions by Nevin Climenhaga, Christos Kyriacou, Michael Hannon, Kevin Wallbridge, Annalisa Coliva, and Genia Schönbaumsfeld.

In this Précis, I provide an overview of my Monograph Knowing and Checking: An Epistemological Investigation (Melchior 2019), which is subject to a book symposium organized by the University of Maribor. This volume in Acta Analytica contains contributions by Peter Baumann, Kelly Becker, Marian David, Nenad Miščević, Robert Weston Siscoe, and Danilo Šuster along with my replies.

This book, the first of its kind, puts forward a novel, unified cognitive account of skeptical doubt. Historically, most philosophers have tried to tackle this difficult topic by directly arguing that skeptical doubt is false. But N. Ángel Pinillos does something different. He begins by trying to uncover the hidden mental rule which, for better or worse, motivates our skeptical inclinations. He then gives an account of the broader cognitive purpose of having and applying this rule. Based on these ideas, (...) he shows how we can give a new response to the traditional problem of global skepticism. He also argues that philosophical skepticism is not just something that comes up during philosophical reflection, as David Hume, Charles Sanders Peirce and other philosophers have urged. Instead, it is of great practical significance. The rule which produces skepticism may itself be operative in certain pathologies such as obsessive-compulsive disorder, in creative endeavors, and in conspiratorial thinking. The rule can also explain some of our reluctance to trust statistical evidence, especially in legal settings. More broadly, this volume aims to breathe new life into a classic problem in philosophy by tackling it from a new perspective and exploring new areas of application. The book will be of interest to philosophers, psychologists and anyone interested in the human capacity to doubt and to question our beliefs. (shrink)

Many epistemologists believe that the distinction between the genesis and the validity of a belief is a fundamental presupposition of adequate epistemological reflection. In this article it will be argued that the arguments for this majority conviction are not convincing. As an alternative it is suggested that the distin- ction between epistemic and non-epistemic procedures should be regarded as fundamental for epistemology.

Both sensitivity and safety theorists concur that their accounts should be relativized to the same method that one employs in the actual world. However, properly individuating methods has proven to be a tricky matter. In this regard, Nozick (Philosophical Explanations, Harvard University Press, Cambridge, 1981) proposes a Same-Experience-Same-Method Principle: if the experiences associated with two method tokens are the same, they are of the same type of method. This principle, however, has been widely rejected by recent safety and sensitivity theorists. (...) In this paper, I raise an argument in favor of Nozick: not endorsing the principle leads to some rather implausible consequences when certain skeptical scenarios are considered—i.e., scenarios in which skeptical possibilities are ‘close’. Additionally, this argument reveals some important lessons about skepticism in general and the place of modal accounts of knowledge in the internalism/externalism debate. (shrink)

The Cartesian arguments for external world skepticism are usually considered to be significant for at least two reasons: they seem to present genuine paradoxes and that providing an adequate response to these arguments would reveal something epistemically important about knowledge, justification, and/or our epistemic position to the world. Using only premises and reasoning the skeptic accepts, I will show that the most common Cartesian argument for external world skepticism leads to a previously unrecognized self-undermining dilemma: it either leads to a (...) reductio ad absurdum, or to avoid this reductio the skeptic must accept that this argument is epistemically idle—it does not provide any support for external world skepticism. Either way, this Cartesian argument cannot legitimately threaten or even call into question our beliefs about the external world. And thus, either way, this Cartesian argument for external world skepticism is not epistemically significant—it is not a genuine paradox and adequately responding to it need not reveal anything epistemically important. (shrink)

In this paper, I offer reasons for thinking that two prominent sceptical arguments in the literature – the underdetermination-based sceptical argument and the closure-based sceptical argument – are less philosophically interesting than is commonly supposed. The underdetermination-based argument begs the question against a non-sceptic and can be dismissed with little fanfare. The closure-based argument, though perhaps not question-begging per se, does rest upon contentious assumptions that a non-sceptic is under no pressure to accept.

Various theorists contend that we may live in a computer simulation. David Chalmers in turn argues that the simulation hypothesis is a metaphysical hypothesis about the nature of our reality, rather than a sceptical scenario. We use recent work on consciousness to motivate new doubts about both sets of arguments. First, we argue that if either panpsychism or panqualityism is true, then the only way to live in a simulation may be as brains-in-vats, in which case it is unlikely that (...) we live in a simulation. We then argue that if panpsychism or panqualityism is true, then viable simulation hypotheses are substantially sceptical scenarios. We conclude that the nature of consciousness has wide-ranging implications for simulation arguments. (shrink)

This article develops a logical (or semantic) response to scepticism about the existence of an external world. Specifically, it is argued that any doubt about the existence of an external world can be proved to be false, but whatever appears to be doubt about the existence of an external world that _cannot_ be proved to be false is nonsense, insofar as it must rely on the assertion of something that is logically impossible. The article further suggests that both G. E. (...) Moore and Ludwig Wittgenstein worked towards the same solution but left their work unfinished. (shrink)

A certain brand of skeptical argument appeals to the thought that our inability to subjectively discriminate between competing hypotheses means that we are unwarranted in believing in either. Externalists respond by pointing out that such arguments depend on an internalist conception of warrant that we would do well to reject. This strategy has been criticised by Crispin Wright who argues that if we pursue the implications of externalism sufficiently far we find that it is ultimately unstable or incoherent. I first (...) rehearse the simple externalist anti-skeptical position. I then present Wright’s argument for the externalist instability, offering a clearer way of understanding its central claim. Finally, I show that the instability in fact arises due to hidden internalist assumptions about evidence and that rid of these assumptions the externalist position is stable after all. (shrink)

Duncan Pritchard recently proposed a Wittgensteinian solution to closure-based skepticism. According to Wittgenstein, all epistemic systems assume certain truths. The notions that we are not disembodied brains, that the Earth has existed for a long time and that one’s name is such-and-such all function as “hinge commitments.” Pritchard views a hinge commitment as a positive propositional attitude that is not a belief. Because closure principles concern only knowledge-apt beliefs, they do not apply to hinge commitments. Thus, from the fact that (...) a subject knows that he is sitting in a room, and the fact that the subject’s sitting in a room entails his bodily existence, it does not follow that the subject also knows that he is not an envatted brain. This paper rejects Pritchard’s non-belief reading of hinge commitments. I start by showing that the non-belief reading fails to solve the skeptical paradox because the reasons that Pritchard uses to support the non-belief reading do not exempt hinge propositions from closure principles. I then proceed to argue that the non-belief reading is false as it claims that hinge commitments, unlike ordinary beliefs, are rationally unresponsive—with the help of a scenario in which a subject’s experience is internally chaotic, we can safely conclude that the hinge commitment that one is not systematically mistaken about the world is equally responsive to one’s evidential situations. (shrink)

The paper defends Cartesian skepticism by an argument relying on internalism and infallibilism. It argues that this sort of skepticism gives the best explanation of our intuitions and ordinary epistemic practices.

According to the idealist, facts about phenomenal experience determine facts about the physical world. Any such view must account for illusions: cases where there is a discrepancy between the physical world and our experiences of it. In this paper, I critique some recent idealist treatments of illusions before presenting my own preferred account. I then argue that, initial impressions notwithstanding, it is actually the realist who has difficulties properly accounting for illusions.

There are brains in vats (BIVs) in the actual world. These “cerebral organoids” are roughly comparable to the brains of three-month-old foetuses, and conscious cerebral organoids seem only a matter of time. Philosophical interest in conscious cerebral organoids has thus far been limited to bioethics, and the purpose of this paper is to discuss cerebral organoids in an epistemological context. In doing so, I will argue that it is now clear that there are close possible worlds in which we are (...) BIVs. Not only does this solidify our intuitive judgement that we cannot know that we are not BIVs, but it poses a fundamental problem for both the neo-Moorean (i.e. safety-based) antisceptical strategy, which purports to allow us to know that we aren’t BIVs, and the safety condition on knowledge itself. Accordingly, this case is especially instructive in illustrating just how epistemologically relevant empirical developments can be. (shrink)

An orthodox sceptical hypothesis claims that one’s belief that “I am not a brain-in-a-vat (BIV)” (or any other ordinary anti-sceptical belief) is insensitive. A form of sensitivity-based scepticism, can thus be constructed by combining this orthodox hypothesis with the sensitivity principle and the closure principle. Unlike traditional solutions to the sensitivity-based sceptical problem, this paper will propose a new solution—one which does not reject either closure or sensitivity. Instead, I argue that sceptics’ assumption that one’s ordinary anti-sceptical beliefs are insensitive (...) will give rise to self-contradiction. The orthodox sceptical hypothesis is thus revealed to be incoherent and arbitrary. Given that there is no coherent reason to presuppose our ordinary anti-sceptical beliefs to be insensitive, the argument for sensitivity-based scepticism can thus be blocked at a lower epistemological cost. (shrink)

Going about our daily lives in an orderly manner requires us, once we are aware of them, to dismiss many metaphysical possibilities. We take it for granted that we are not brains in vats, or living in the Matrix, or in an extended dream. Call these things that we take for granted “anti-skeptical assumptions”. What should a reflective agent who believes these things think of these beliefs? For various reasons, it can seem that we do not have evidence for such (...) anti-skeptical assumptions. Are anti-skeptical assumptions, then, beliefs that one may rationally hold without evidence for them – indeed, even in the face of a positive judgment that one lacks evidence for them? I survey and criticize some prominent answers to this question, and then offer a positive view that blends externalism about evidence with a mild, qualified kind of pragmatism. The view I offer aims to do justice to the sense that anti-skeptical assumptions are evidentially groundless while also maintaining that one cannot rationally believe something that one judges oneself to lack sufficient evidence for. (shrink)

Cartesian arguments for global skepticism about the external world start from the premise that we cannot know that we are not in a Cartesian scenario such as an evil-demon scenario, and infer that because most of our empirical beliefs are false in such a scenario, these beliefs do not constitute knowledge. Veridicalist responses to global skepticism respond that arguments fail because in Cartesian scenarios, many or most of our empirical beliefs are true. Some veridicalist responses have been motivated using verificationism, (...) externalism, and coherentism. I argue that a more powerful veridicalist response to global skepticism can be motivated by structuralism, on which physical entities are understood as those that play a certain structural role. I develop the structuralist response and address objections. (shrink)

_ Source: _Volume 8, Issue 1, pp 51 - 61 _Epistemic Angst: Radical Skepticism and the Groundlessness of our Believing_. By Duncan Pritchard. Princeton and Oxford: Princeton University Press, 2016. Pp. xv + 239. ISBN 978-0-691-16723-7.

Epistemic externalism offers one of the most prominent responses to the sceptical challenge. Externalism has commonly been interpreted as postulating a crucial asymmetry between the actual-world agent and their brain-in-a-vat counterpart: while the actual agent is in a position to know she is not envatted, her biv counterpart is not in a position to know that she is envatted, or in other words, only the former is in a position to know whether or not she is envatted. In this paper, (...) I argue that there is in fact no such asymmetry: assuming epistemic externalism, both the actual world agent and their biv counterpart are in a position to know whether or not they are envatted. After an introduction, I present the main argument. I examine to what extent the argument survives when one accepts additional externalist-friendly commitments: semantic externalism, a sensitivity condition on knowledge, and epistemic contextualism. Finally, I discuss the implications of my conclusion to a variety of debates in epistemology. (shrink)

The orthodox position in epistemology, for both externalists and internalists, is that a subject in a ‘bad case’—a sceptical scenario—is so epistemically badly off that they cannot know how badly off they are. Ofra Magidor contends that externalists should break ranks on this question, and that doing so is liberating when it comes time to confront a number of central issues in epistemology, including scepticism and the new evil demon problem for process reliabilism. In this reply, I will question whether (...) Magidor’s argument should persuade externalists, whether it really engages with the orthodox view on what subjects in bad cases can know, and whether the dispute is, as Magidor insists, a significant one for contemporary epistemology. (shrink)

Goldberg 2016 is a collection of papers dedicated to Putnam’s (1981) brain in a vat (‘BIV’) scenario. The collection divides into three parts, though the issues are inter-connected. Putnam uses conceptual tools from philosophy of language in order to establish theses in epistemology and metaphysics. Putnam’s BIV is considered a contemporary version of Descartes’s skeptical argument of the Evil Genius, but I argue that deception (the possibility of having massively false belief) is not essential, externalism does all the anti-skeptical work. (...) The largest section in the collection covers Putnam’s model-theoretic argument (MTA) against metaphysical realism (MR) and its connections with the brain in vat argument (BVA). There are two camps—unifiers (there is a deep connection in Putnam’s thoughts on BVA, MTA and MR) and patchwork theorists and I try to provide some support for the second camp. All of the papers in the collection are discussed and the anti-skeptical potential of BVA is critically assessed. (shrink)

Here, I shall be examining the viability of a Moorean response to the Argument from Ignorance; i.e., one that tries to rebut the argument by denying its first premise that we cannot have knowledge that we are not BIVs. After first explicating the Argument from Ignorance in detail, I then go on to try and motivate this approach by critically examining two alternative approaches to dealing with radical scepticism: closure-denial, and attributer contextualism. Finding them wanting, I then turn to a (...) Moorean 'argument from knowledge', and diagnose why as it stands such an approach is ineffective, before going on to explore whether one can wed such an argument to an externalist framework in order to provide a more satisfying answer to the question of how one can know the denials of sceptical hypotheses, one that does not simply beg the question against the sceptic. Finding such a neo-Moorean approach to be initially promising, I then conclude by arguing that ultimately it winds up saving knowledge simpliciter only at the cost of losing rationally-grounded knowledge to the sceptic's grasp, and such a result is highly unpalatable. (shrink)

Some modern cosmological models predict the appearance of Boltzmann Brains: observers who randomly fluctuate out of a thermal bath rather than naturally evolving from a low-entropy Big Bang. A theory in which most observers are of the Boltzmann Brain type is generally thought to be unacceptable, although opinions differ. I argue that such theories are indeed unacceptable: the real problem is with fluctuations into observers who are locally identical to ordinary observers, and their existence cannot be swept under the rug (...) by a choice of probability distributions over observers. The issue is not that the existence of such observers is ruled out by data, but that the theories that predict them are cognitively unstable: they cannot simultaneously be true and justifiably believed. (shrink)

Radical skepticism relies on the hypothesis that one could be completely cut off from the external world. In this paper, I argue that this hypothesis can be rationally motivated by means of a conceivability argument. Subsequently, I submit that this conceivability argument does not furnish a good reason to believe that one could be completely cut off from the external world. To this end, I show that we cannot adequately conceive scenarios that verify the radical skeptical hypothesis. Attempts to do (...) so fall prey to one or another of three pitfalls: they end up incomplete, reveal a deep contradiction or recreate a non-skeptical hypothesis. I use these results to improve upon Pritchard’s recent attempt at undercutting radical skepticism. (shrink)

This paper reassesses the case against Evidential Externalism, the thesis that one's evidence fails to supervene on one's non-factive mental states, focusing on two objections to Externalism due by Nicholas Silins: the armchair access argument and the supervenience argument. It also examines Silins's attempt to undermine the force of one major source of motivation for Externalism, namely that the rival Internalist picture of evidence is implicated in some central arguments for scepticism. While Silins concludes that the case against Evidential Externalism (...) is surprisingly strong, reassessing the arguments supports the opposite conclusion; the objections to Externalism are weak, and for all Silins has shown it may well have unmatched advantages when it comes to resisting scepticism. (shrink)

I will argue that cases of massive deception, such as New Evil Demon cases, as well as one-off cases of local deception present challenges to views according to which epistemic reasons, epistemic warrant, epistemic rationality or epistemic norms are factive. In doing so, I will argue is that proponents of a factive turn in epistemology should observe important distinctions between what are often simply referred to as ‘bad cases.’ Recognizing epistemologically significant differences between deception cases raises serious challenges for those (...) who deny a central role for non-factive aspects of epistemology. (shrink)

Epistemological disjunctivism is a philosophical theory that has received special attention in the recent years. Particularly because it has been seen by many as a way of renewing discussions that range from the nature of justification of our daily beliefs to the possibility of unveiling the structure of the problem of radical skepticism and of responding to it. Duncan Pritchard is one of the authors who have offered a particular view of disjunctivism and ways of conceiving of disjunctivist treatments to (...) such questions. His work has as its main source of inspiration the seminal work of John McDowell. In this paper, I present a way of understanding the problem ofradicalskepticism and the mannerin which epistemological disjunctivism aimsto offer solutionsto it. In orderto do that, I present McDowell’s general proposal and discuss in which way his account differs from Pritchard’s own disjunctivism. At the end, I try to show how Pritchard’s approach tries to respond to radical skepticism not only by appealing to a disjunctivist reading of our epistemic position, but also by offering a revision of our structure of reasons. (shrink)

ABSTRACTHilary Putnam provides an anti-skeptical argument motivated by semantic externalism. He argues that our best theorizing about what it takes to experience, think, and so on, entails that the world is much as we take it to be. This fact eliminates the possibility of radical skeptical scenarios, where from our perspective everything seems as it does in the actual case, but we are widely and systematically mistaken. I think that this approach is generally correct, and that it is the most (...) promising strategy for undermining radical skepticism. There are, however, well-discussed difficulties with Putnam's way of pursuing this strategy. I argue that in order to avoid these objections we will have to be more radical externalists than Putnam proposed; in particular, we will have to beperspectival externalists. According to perspectival externalism, a subject's reliable relations to her environment play a crucial role in determining not only the contents of her mental events, but also what it is like for her to grasp those contents. While semantic externalism is widely accepted in epistemology, perspectival externalism is not. I argue that perspectival externalism is independently more plausible than mere semantic externalism, and that such an account can enable us to better pursue Putnam's anti-skeptical strategy. (shrink)

In this paper, I argue that, if transcendental arguments are to proceed from premises that are acceptable to the skeptic, the Transcendental Premise, according to which “X is a metaphysically necessary condition for the possibility of Y,” must be grounded in considerations of conceivability and possibility. More explicitly, the Transcendental Premise is based on what Szabó Gendler and Hawthorne call the “conceivability-possibility move.” This “inconceivability-impossibility” move, however, is a problematic argumentative move when advancing transcendental arguments for the following reasons. First, (...) from “S cannot conceive of P” it doesn’t necessarily follow that P is inconceivable. Second, from “P is inconceivable” it doesn’t necessarily follow that P is metaphysically impossible. Third, rather than block skeptical doubts, the conceivability-possibility move introduces skeptical doubts. For these reasons, transcendental arguments fail to deliver on their promise to overcome skeptical doubts. (shrink)

In this paper, I argue that arguments from skeptical hypotheses for external world skepticism derive their support from a skeptical argument from the distinction between appearance and reality. This skeptical argument from the appearance/reality distinction gives the external world skeptic her conclusion without appealing to skeptical hypotheses and without assuming that knowledge is closed under known entailments. If this is correct, then this skeptical argument from the appearance/reality distinction poses a new skeptical challenge that cannot be resolved by denying skeptical (...) hypotheses or knowledge closure. (shrink)

Putnam’s semantic argument against the BIV hypothesis and Sosa’s argument against dream skepticism based on the imagination model of dreaming share some important structural features. In both cases the skeptical option is supposed to be excluded because preconditions of its intelligibility are not fulfilled (affirmation and belief in the dream scenario, thought and reference in the BIV scenario). Putnam’s reasoning is usually interpreted differently, as a classic case of deception, but this feature is not essential. I propose to interpret BIV’s (...) utterances as cases of reference failure best captured by truth-value gaps. Both anti-skeptical strategies are then vulnerable to the same type of objections (how do we know what state we are in or how do we know what kind of language do we speak). (shrink)

Recent discussions in cognitive science and the philosophy of mind have defended a theory according to which we live in a virtual world akin to a computer simulation, generated by our brain. It is argued that our brain creates a model world from a variety of stimuli; this model is perceived as if it was external and perception-independent, even though it is neither of the two. The view of the mind, brain, and world, entailed by this theory has some peculiar (...) consequences which have rarely been explored in detail. This paper sets out virtual world theory and relates it to various central philosophical problems, the role of the perceiver and the problem of the existence of the external world ). The second part suggests three interpretations of virtual world theory, two familiar ones and a somewhat less familiar one. The remainder of the paper argues that the irrealist interpretation is the one we should adopt. (shrink)

Hilary Putnam’s BIV argument first occurred to him when ‘thinking about a theorem in modern logic, the “Skolem–Löwenheim Theorem”’ (Putnam 1981: 7). One of my aims in this paper is to explore the connection between the argument and the Theorem. But I also want to draw some further connections. In particular, I think that Putnam’s BIV argument provides us with an impressively versatile template for dealing with sceptical challenges. Indeed, this template allows us to unify some of Putnam’s most enduring (...) contributions to the realism/antirealism debate: his discussions of brains-in-vats, of Skolem’s Paradox, and of permutations. In all three cases, we have an argument which does not merely defeat the sceptic; it also shows us that we must reject some prima facie plausible philosophical picture. (shrink)

A sensible epistemologist may not see how she could know that she is not a brain in a vat ; but she doesn’t panic. She sticks with her empirical beliefs, and as that requires, believes that she is not a BIV. (She does not inferentially base her belief that she is not a BIV on her empirical knowledge—she rejects that ‘Moorean’ response to skepticism.) Drawing on the psychological literature on metacognition, I describe a mechanism that’s plausibly responsible for a sensible (...) epistemologist coming to believe she is not a BIV. I propose she thereby knows that she is not a BIV. The particular belief-forming mechanism employed explains why she overlooks this account of how she knows she is not a BIV, making it seem that there is no way for her to know it. I argue this proposal satisfactorily resolves the skeptical puzzle. (shrink)