Brains in Vats

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)

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)

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 in respect to 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 supervenient to the organism-environment system. They can be distinguished from the 'corresponding' hallucinations because the former result from a controlled process of attunement to the environment, whereas hallucinations are passive and insensible to the exploratory activities of the perceptual system. Finally, the ecological disjunctivism, inasmuch as it is immune to the causal argument, is more advantageous in relation to the negative and positive disjunctivisms. (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)

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)

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)

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.

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.

There are brains in vats 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 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)

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)

_ 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)

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)

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)

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)

As formulated by Duncan Pritchard and John McDowell, epistemological disjunctivism is the claim that perceptual experience can provide the subject with epistemic justification that is reflectively accessible and externally grounded at the same time. Pritchard calls this thesis ‘the holy grail of epistemology’, since it reconciles two traditionally rival theories of justification, namely epistemic internalism and epistemic externalism. The main objection against epistemological disjunctivism thus understood is that it does not do justice to the well-known internalist intuitions expressed in The (...) New Evil Demon and Brain-in-a-Vat scenarios. I defend epistemological disjunctivism from this objection by indicating that those who apply to such scenarios commit themselves to implausible views in the philosophy of mind. I conclude that epistemological disjunctivism accurately expresses the epistemological attitude of a non-reductive materialist regarding the body-mind problem. (shrink)

Tim Button explores the relationship between minds, words, and world. He argues that the two main strands of scepticism are deeply related and can be overcome, but that there is a limit to how much we can show. We must position ourselves somewhere between internal realism and external realism, and we cannot hope to say exactly where.

On a common view of scenario-based sceptical arguments sceptical scenarios are error-possibilities, i.e. their point is to introduce the possibility of having only false beliefs. However, global error is impossible for purely logical/conceptual reasons: Even if one’s beliefs are consistent, the negations of one’s beliefs need not be consistent as well. My paper deals with the question of what the consequences of this result are. Two attempts at repairing scenario-based sceptical arguments within the framework of understanding sceptical scenarios as error-possibilities (...) are found wanting. Instead, what should be given up is the assumption that sceptical scenarios are error-possibilities. What is thought-provoking about the scenario of the brain in a vat is not that none of its empirical beliefs are true, but that all of its empirical beliefs fall short of knowledge at the same time. Hence, sceptical scenarios are not error-possibilities, but ignorance possibilities. If this is so, both the closure argument and the underdetermination argument commit a subtle mistake and should be replaced by slightly different arguments. The principle of excluded ignorance-possibilities turns out to be an epistemological principle that is faithful to scepticism’s tenets without misinterpreting sceptical scenarios as error-possibilities. (shrink)

: Radical sceptical possibilities challenge the anti-realist view that truth consists in ideal rational acceptability. Putnam, as part of his defence of an anti-realist view, subjected the case of the brain in a vat to a semantic externalist treatment, which aimed to maintain the desired connection between truth and ideal rational acceptability. It is argued here that self-consciousness poses special problems for this externalist strategy. It is shown how, on a standard model of first-person reference, Putnam's brain in a vat (...) will be mistaken in its rational self-ascription of externalist predicates. The natural response, which employs an alternative model of first-person reference, is shown to have the equally realist consequence that there are enquiry-transcendent truths about the self. (shrink)

The argument against skepticism relying on content externalism, which was made famous by Hilary Putnam, has been considered inconclusive by many philosophers. However, some believe that this argument has precluded the possibility of skeptical hypotheses. These hypotheses typically are fictional scenarios where a deceptive power makes your experiences indistinguishable from those you would have if you were not in such a scenario, making most of your justified belief false. Some philosophers, such as Anthony Brueckner and Jon Altschul, have taken this (...) problem seriously and, in response to Putnam, have developed an alternative to the argument from ignorance: the piecemeal fashion strategy. I wish to defend, contra Brueckner and Altschul, the idea that some skeptical hypotheses remain untouched by content externalism, making the piecemeal fashion strategy obsolete. (shrink)

Language users ordinarily suppose that they know what thoughts their own utterances express. We can call this supposed knowledge minimal self-knowledge. But what does it come to? And do we actually have it? Anti-individualism implies that the thoughts which a person's utterances express are partly determined by facts about their social and physical environments. If anti-individualism is true, then there are some apparently coherent sceptical hypotheses that conflict with our supposition that we have minimal self-knowledge. In this book, Anthony Brueckner (...) and Gary Ebbs debate how to characterize this problem and develop opposing views of what it shows. Their discussion is the only sustained, in-depth debate about anti-individualism, scepticism and knowledge of one's own thoughts, and will interest both scholars and graduate students in philosophy of language, philosophy of mind and epistemology. (shrink)

Within the framework of the epistemological debate on disagreement, this paper aims to examine the sceptical thesis that holds that, if it is impossible to rationally choose among two excluding positions, the only sensible or rational thing to do is to suspend judgement. The idea that ordinary life does not constitute the source of scepticism is presented, which rules out real disagreement between epistemic pairs as its foundation. Sceptical scenes differ ontologically from everyday scenes, without such ontological difference entailing an (...) epistemic difference, since epistemic practices do not vary from one sceptical scene to other types of scenes. (shrink)

According to epistemic internalism, the only facts that determine the justificational status of a belief are facts about the subject’s own mental states, like beliefs and experiences. Externalists instead hold that certain external facts, such as facts about the world or the reliability of a belief-producing mechanism, affect a belief’s justificational status. Some internalists argue that considerations about evil demon victims and brains in vats provide excellent reason to reject externalism: because these subjects are placed in epistemically unfavorable settings, externalism (...) seems unable to account for the strong intuition that these subjects’ beliefs are nonetheless justified. I think these considerations do not at all help the internalist cause. I argue that by appealing to the anti-individualistic nature of perception, it can be shown that skeptical scenarios provide no reason to prefer internalism to externalism. (shrink)

A well known skeptical paradox rests on the claim that we lack warrant to believe that we are not brains in a vat. The argument for that claim is the apparent impossibility of any evidence or argument that we are not BIVs. Many contemporary philosophers resist this argument by insisting that we have a sort of warrant for believing that we are not BIVs that does not require having any evidence or argument. I call this view ‘New Rationalism’. I argue (...) that New Rationalists are committed to there being some evidence or argument for believing that we are not BIVs anyway. Therefore, New Rationalism, since its appeal is that it purportedly avoids the problematic commitment to such evidence or argument, undermines its own appeal. We cannot avoid the difficult work of coming up with evidence or argument by positing some permissive sort of warrant. (shrink)

In this paper, I will clarify Jonathan Schaffer's; debasing scepticism, highlighting its logical structure. 1 In many current discussions of scepticism, its scope is limited to propositions about the external world which, if known at all, are known a posteriori. The standard sceptical set-up goes as follows. The sceptic specifies a sceptical hypothesis, or counterpossibility, that is incompatible with the external-world propositions that I claim to know. The hypothesis – e.g. that I am a brain in a vat – is (...) claimed by the sceptic to be within the realm of metaphysical possibility. The sceptical argument, in a nutshell, runs as follows. Choose some external-world proposition that I claim to know, say H = I have hands. By the principle that knowledge is closed under known entailment, if I know H, then I know ∼SK = I am not a handless brain in a vat. My evidence does not enable me to know ∼SK. Hence I …. (shrink)

The problem of philosophical skepticism relates to the difficulty involved in underwriting the claim that we know anything of spatio-temporal reality. It is often claimed, in fact, that proper philosophical scrutiny reveals quite the opposite from what common sense suggests. Knowledge of external reality is thought to be even quite obviously denied to us as a result of the alleged fact that we all fail to know that certain skeptical scenarios do not obtain. A skeptical scenario is one in which (...) we have neurological occurrences just like any normal situation in which we actually perceive spatio-temporal objects, but where we are deceived in some sense as a result of the manipulation of our brains from some outside source. In this work I attempt to address the problem of philosophical skepticism by claiming that most of us are able to come to know plenty about external reality, since we can come to realize that a certain philosophical theory of perception is correct. The theory I have in mind is what I call a non-cognitive theory of perception. According to this view, perceptual experience is defined by continuous, sensitive behavioral interaction with spatio-temporal objects of the appropriate size, shape, hardness, speed, etc. Knowing that this theory of perception is correct is equivalent to knowing that we know plenty about external reality. This is ultimately because by knowing that a non-cognitive theory of perception is true, we know that any skeptical scenario must fail to obtain. The structure of the work proceeds by first discussing the significance of the problem of philosophical skepticism in some detail. Chapter 1 lays out how the problem does indeed forcefully arise if it is conceded that we fail to know that the skeptical scenarios fail to obtain. Chapter 2 develops the sort of view of our epistemological situation that falls out of accepting without qualification that the problem exists. Chapter 3 examines and criticizes certain popular responses to the skeptical problem. The main goal of these first three preliminary chapters is to indicate that once it is admitted that we fail to know that the skeptical scenarios fail to obtain, the problem of philosophical skepticism forcefully presents itself. Chapter 4, however, attacks the idea that we fail to know that the skeptical scenarios fail to obtain. In this chapter I argue that this idea is wedded to the position that a certain theory of perception is correct. The theory in question is what I call a conjunctive theory of veridical experience. According to this view, normal experience of spatio-temporal objects occurs when a subject has a certain perceptual experience, and that experience also happens to match up with and/or be satisfied by what is really the case. Only when a theory of this sort is assumed, I argue, is the claim that we fail to know that the skeptical scenarios fail to obtain found to be obvious. In chapter 5 I argue that, in fact, a non-cognitive theory, rather than a conjunctive theory, is the correct view to maintain. In the final chapter 6 I develop the epistemological position that falls out of accepting a non-cognitive theory. (shrink)

Is matter real? Are persons real? Is time real? This Very Short Introduction discusses what, if anything, is "real" by looking at a variety of arguments from philosophy, physics, and cognitive science. The book shows that the question "what is real?" is not some esoteric puzzle that only philosophers ponder. Scientists also ask this question when they investigate whether candidates for the fundamental constituents of matter are actually "out there" or just a mere abstraction from a successful theory and cognitive (...) scientists ask it when trying to find out which set of the bewildering array of data processed by our brain could constitute the basis for the self. -/- Contents: -/- Introduction 1. What is real? Dreams and simulations 2. Is matter real? 3. Are persons real? 4. Is time real? Conclusion. (shrink)

Suppose that a team of neurosurgeons and bioengineers were able to remove your brain from your body, suspend it in a life-sustaining vat of liquid nutrients, and connect its neurons and nerve terminals by wires to a supercomputer that would stimulate it with electrical impulses exactly like those it normally receives when embodied. According to this brain-in-a-vat thought experiment, your envatted brain and your embodied brain would have subjectively indistinguishable mental lives. For all you know—so one argument goes—you could be (...) such a brain in a vat right now.1 Daniel Dennett calls this sort of philosophical thought experiment an “intuition pump” (Dennett 1995). An intuition pump is designed to elicit certain intuitive convictions, but is not itself a proper argument: “intuition pumps are fine if they’re used correctly, but they can also be misused. They’re not arguments, they’re stories. Instead of having a conclusion, they pump an intuition. They get you to say ‘Aha! Oh, I get it!’ (Dennett 1995, p. 182). Philosophers have used the brain-in-a-vat story mainly to raise the problem of radical skepticism and to elicit various intuitions about meaning and knowledge (Putnam 1981). The basic intuition the story tries to pump is that the envatted brain, though fully conscious, has systematically false beliefs about the world, including itself. Some philosophers reject this intuition. They propose that the envatted brain’s beliefs are really about its artificial environment or that it.. (shrink)

The paper is devoted to a discussion and critical evaluation of antisceptical arguments in epistemology that are based on causal theory of reference, with the special focus upon the revised version of the Hilary Putnam‘s Brain-in-a-Vat argument presented by Olaf Müller. Müller claims that his argument is based on the metaphysically neutral principles of semantic externalism and disquotation, however more thorough analysis of these principles and of the possibility to use them for antisceptical purposes reveals the flaw in his argument. (...) It seems that Müller reaches his conclusion by confusing the syntactically identical, though semantically distinct utterances in BIV language, non-BIV language, and metalanguage. The reconstruction and analysis of Müller‘s argument shows that his argument, provided that its premises are formulated carefully so as not to beg the question against the sceptic, fails to establish anything more than the original version provided by Putnam.Keywords: scepticism, Olaf Müller, semantic externalism, disquotation, brain-in-a-Vat. (shrink)