In this, the first book to address the ongoing debate, Plantinga presents his influential thesis and responds to critiques by distinguished philosophers from a ...

This paper addresses the question whetherintrospection plus externalism about mental contentwarrant an a priori refutation of external-worldskepticism and ontological solipsism. The suggestionis that if thought content is partly determined byaffairs in the environment and if we can havenon-empirical knowledge of our current thoughtcontents, we can, just by reflection, know about theworld around us – we can know that our environment ispopulated with content-determining entities. Afterexamining this type of transcendental argument anddiscussing various objections found in the literature,I argue that the notion (...) of privileged self-knowledgeunderlying this argument presupposes that we canlearn, via introspection, that our so-called thoughtsare propositional attitudes rather than contentlessstates. If, however, externalism is correct andthought content consists in the systematic dependencyof internal states on relational properties, we cannotknow non-empirically whether or not we havepropositional attitudes. Self-knowledge (apropositional attitude) is consistent with us lackingthe ability to rule out, via introspection, thepossibility that we don't have any propositionalattitudes. Self-knowledge provides us with knowledgeof what is in our minds, but not that we haveminds. Hence, the combination of externalism with thedoctrine of privileged self-knowledge does not allowfor an a priori refutation of skepticism and istherefore unproblematic. (shrink)

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: (1) Why is an explanation of our experience offered by the skeptical hypothesis more complex than our standard explanation? (2) 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)

The Neo-Moorean response to the radical skeptical challenge boldly maintains that we can know we’re not the victims of radical skeptical hypotheses; accordingly, our everyday knowledge that would otherwise be threatened by our inability to rule out such hypotheses stands unthreatened. Given the leverage such an approach has against the skeptic from the very start, the Neo-Moorean line is an especially popular one; as we shall see, though, it faces several commonly overlooked problems. An initial problem is that this particular (...) brand of anti-skeptical strategy is available only to a theory of knowledge that will compromise itself to especially weak epistemic standards—indeed, standards as weak as our epistemic grounds are for accepting the denials of skeptical hypotheses. With this said, the aim here is to investigate whether the Neo-Moorean line could be advanced against the skeptic in a way that wouldn’t require wholesale lowering of epistemic standards. Unfortunately, as we’ll see, Sosa’s (2007; 2009) view as well as what I argue to be the other two most plausible contender-views for maintaining a Neo-Moorean line—Greco’s and Pritchard’s—run (for similar reasons) into dead ends. The way forward, I’ll argue, is to take on board a unique variety of robust virtue epistemology accord­ing to which knowledge is thought to be situated a certain way within a gradient balance between ability and luck. (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)

Disjunctivists hold that perceiving external objects is fundamentally different from any experiential state that is not a perception. In fact, roughly speaking, disjunctivists say that they have nothing in common. Suppose that it appears to someone as though she perceives something. Disjunctivists say that there are two disparate sorts of facts that could make this true. Either she is genuinely perceiving something, or she is in an experiential state of merely apparent perception. An apparent perception is fundamentally unlike a perception. (...) Disjunctivists differ in what they say the fundamental difference is. We’ll get to some of that shortly. First I’ll say where I’m headed here. (shrink)

In Reason, Truth, and History Hilary Putnam has presented an anti-skeptical argument purporting to prove that we are not brains in a vat. How exactly the argument goes is somewhat controversial. A number of competing "recon¬structions" have been proposed. They suffer from a defect which they share with what seems to be Putnam's own version of the argument. In this paper, I examine a very simple and rather natural reconstruction of the argument, one that does not employ any premises in (...) which a sentence, viz. the sentence 'I am a brain in a vat', is mentioned rather than used. In this respect my version of the argument is importantly different from what appears to be Putnam's own version. (shrink)

This paper shows that the resources mobilized by recent arguments against individualism in the philosophy of mind also suffice to construct a good argument against a Humean-style skepticism about our knowledge of extra-mental reality. The argument constructed, however, will not suffice to lay to rest the attacks of a truly global skeptic who rejects the idea that we usually know what our occurrent mental states are.

Given anti-individualism, a subjectmight have a priori (non-empirical)knowledge that she herself is thinking thatp, have complete and exhaustiveexplicational knowledge of all of the conceptscomposing the content that p, and yetstill need empirical information (e.g.regarding her embedding conditions and history)prior to being in a position to apply herexhaustive conceptual knowledge in aknowledgeable way to the thought that p. This result should be welcomed byanti-individualists: it squares with everythingthat compatibilist-minded anti-individualistshave said regarding e.g. the compatibility ofanti-individualism and basic self-knowledge;and more importantly it (...) contains the crux of aresponse to McKinsey-style arguments againstanti-individualism. (shrink)

Part 1 argues that, despite rhetorical appearances, McDowell accepts a standard version of epistemic externalism. Moreover, epistemic externalism plays an important role in McDowell’s response to skepticism. Part 2 argues that, contra McDowell, epistemic externalism is necessary for rejecting skepticism, and content externalism is not sufficient for rejecting skepticism.

We know things that entail things we apparently cannot come to know. This is a problem for those of us who trust that knowledge is closed under entailment. In the paper I discuss the solutions to this problem offered by epistemic disjunctivism and contextualism. The contention is that neither of these theories has the resources to deal satisfactory with the problem.

Radical skepticism about the external world is founded on two assumptions: one is that the mind and the external world are logically independent; the other is that all our evidence for the nature of that world consists of facts about our minds.

McDowell has argued that external world scepticism is a pressing problem only in so far as we accept, on the basis of the argument from illusion, the claim that perceiving that p and hallucinating that p involve a highest common factor.

[Brian P. McLaughlin] In recent years, some philosophers have claimed that we can know a priori that certain external world skeptical hypotheses are false on the basis of a priori knowledge that we are in certain kinds of mental states, and a priori knowledge that those mental states are individuated by contingent environmental factors. Appealing to a distinction between weak and strong a priority, I argue that weakly a priori arguments of this sort would beg the question of whether the (...) skeptical hypothesis under assessment is true, and that the prospect of a sound strongly a priori argument of this sort seems dim. \\\ [David Owens] Contemporary discussion of scepticism focuses on the possibility that most or all of our beliefs might be false. I argue that the hypothesis of massive falsity and the associated 'problem of the external world' are inessential to the scepticisms of Descartes and Hume. What drives Cartesian and Humean scepticism is the demand for certainty: any possibility of error, however local, must be ruled out before we can claim either justified belief or knowledge. Contemporary philosophers have ignored this form of scepticism because they doubt that the demand for certainty can be motivated. But Descartes provides a sound motivation for this demand in the Meditations. (shrink)

[Brian P. McLaughlin] In recent years, some philosophers have claimed that we can know a priori that certain external world skeptical hypotheses are false on the basis of a priori knowledge that we are in certain kinds of mental states, and a priori knowledge that those mental states are individuated by contingent environmental factors. Appealing to a distinction between weak and strong a priority, I argue that weakly a priori arguments of this sort would beg the question of whether the (...) skeptical hypothesis under assessment is true, and that the prospect of a sound strongly a priori argument of this sort seems dim. \\\ [David Owens] Contemporary discussion of scepticism focuses on the possibility that most or all of our beliefs might be false. I argue that the hypothesis of massive falsity and the associated 'problem of the external world' are inessential to the scepticisms of Descartes and Hume. What drives Cartesian and Humean scepticism is the demand for certainty: any possibility of error, however local, must be ruled out before we can claim either justified belief or knowledge. Contemporary philosophers have ignored this form of scepticism because they doubt that the demand for certainty can be motivated. But Descartes provides a sound motivation for this demand in the Meditations. (shrink)

[Brian P. McLaughlin] In recent years, some philosophers have claimed that we can know a priori that certain external world skeptical hypotheses are false on the basis of a priori knowledge that we are in certain kinds of mental states, and a priori knowledge that those mental states are individuated by contingent environmental factors. Appealing to a distinction between weak and strong a priority, I argue that weakly a priori arguments of this sort would beg the question of whether the (...) skeptical hypothesis under assessment is true, and that the prospect of a sound strongly a priori argument of this sort seems dim. \\\ [David Owens] Contemporary discussion of scepticism focuses on the possibility that most or all of our beliefs might be false. I argue that the hypothesis of massive falsity and the associated 'problem of the external world' are inessential to the scepticisms of Descartes and Hume. What drives Cartesian and Humean scepticism is the demand for certainty: any possibility of error, however local, must be ruled out before we can claim either justified belief or knowledge. Contemporary philosophers have ignored this form of scepticism because they doubt that the demand for certainty can be motivated. But Descartes provides a sound motivation for this demand in the Meditations. (shrink)

The tracking theory treats knowledge as counterfactual covariation of belief and truth through a sphere of possibilities. I argue that the tracking theory cannot respect perceptual knowledge, because perceptual belief covaries with truth through a discontinuous scatter of possibilities.

Davidson’s epistemology, like Kant’s, features a transcendental argument as its centerpiece. Both philosophers reject any priority, whether epistemological or conceptual, of the subjective over the objective, attempting thus to solve the problem of the external world. For Davidson, three varieties of knowledge are coordinate—knowledge of the self, of other minds, and of the external world. None has priority. Despite the epistemologically coordinate status of the mind and the world, however, the content of the mind can be shown to entail how (...) it is out in the world. More exactly, Davidson argues, we could not possibly have the beliefs we have, with their contents, unless the world around us was pretty much the way we take it to be, at least in its general outline. We are thus offered a way to argue, to all appearances a priori, from how it is in our minds to how it is in the world. The argument is a priori at least in being free of premises or assumptions about contingent particularities concerning the world around us or our relation to it. From premises about the contents of our propositional attitudes, the argument wends its way to a conclusion about the general lines of how the world around us is structured and populated. Before presenting his own account, Davidson rejects received views of meaning and knowledge. What follows will combine themes from his critique of alternatives with his more positive account and how it deals with the skeptic. (shrink)