What Do Philosophers Do? takes up the leading arguments for radical skepticism from an everyday point of view. A range of philosophical methods are examined and employed, for a revealing portrait of what philosophers do, and perhaps a quiet suggestion for what they should do, for what they do best.

The possibility of justified true belief without knowledge is normally motivated by informally classified examples. This paper shows that it can also be motivated more formally, by a natural class of epistemic models in which both knowledge and justified belief are represented. The models involve a distinction between appearance and reality. Gettier cases arise because the agent's ignorance increases as the gap between appearance and reality widens. The models also exhibit an epistemic asymmetry between good and bad cases that sceptics (...) seem to ignore or deny. (shrink)

In the First Meditation, the Cartesian meditator temporarily concludes that he cannot know anything, because he cannot discriminate dreaming from waking while he is dreaming. To resist the meditator’s conclusion, one could deploy an asymmetry argument. Following Bernard Williams, one could argue that even if the meditator cannot discriminate dreaming from waking while dreaming, it does not follow that he cannot do it while awake. In general, asymmetry arguments seek to identify an asymmetry between a bad case that is entertained (...) as a ground for doubt and a good case in which one takes oneself to know something. My aim in this paper is to consider how effective asymmetry arguments are as an anti-skeptical strategy. I conclude that although asymmetry arguments provide an effective response to dreaming skepticism, they fail as a response to brains-in-a-vat skepticism. (shrink)

What modal relation must a fact bear to a belief in order for this belief to constitute knowledge of that fact? Externalists have proposed various answers, including some that combine externalism with contextualism. We shall find that various forms of externalism share a modal conception of “sensitivity” open to serious objections. Fortunately, the undeniable intuitive attractiveness of this conception can be explained through an easily confused but far preferable notion of “safety.” The denouement of our reflections, finally, will be to (...) show how replacing sensitivity with safety makes it possible to defend plain Moorean common sense against the spurious advantages over it claimed by skeptical, tracking, relevant-alternative, and contextualist accounts. (shrink)

Consider the skeptic about the external world. Let’s straightaway concede to such a skeptic that perception gives us no conclusive or certain knowledge about our surroundings. Our perceptual justification for beliefs about our surroundings is always defeasible—there are always possible improvements in our epistemic state which would no longer support those beliefs. Let’s also concede to the skeptic that it’s metaphysically possible for us to have all the experiences we’re now having while all those experiences are false. Some philosophers dispute (...) this, but I do not. The skeptic I want to consider goes beyond these familiar points to the much more radical conclusion that our perceptual experiences can’t give us any knowledge or even justification for believing that our surroundings are one way rather than another. (shrink)

_ Source: _Volume 8, Issue 3, pp 208 - 222 Penelope Maddy claims that we can have no evidence that we are not being globally deceived by an evil demon. However, Maddy’s Plain Inquirer holds that she has good evidence for a wide variety of claims about the world and her relation to it. She rejects the broadly Cartesian idea that she can’t be entitled to these claims, or have good evidence for them, or know them, unless she can provide (...) a defense of them that starts from nowhere. She likewise rejects the more limited demand for a defense that makes use only of considerations that do not concern the world outside of her mind. She allows that some considerations about the world can be appealed to perfectly appropriately as fully adequate evidence in favor of other considerations about the world. So why can’t the Plain Inquirer rule out global skeptical hypotheses by producing evidence against them that depends upon other considerations about the world? Is there good reason for singling out global skeptical hypotheses such as _I am not being deceived by an evil demon_ as requiring a different kind of treatment? Considerations about epistemic asymmetry and epistemic circularity, as well as Wittgensteinian considerations about the relation between evidence and the real-world and human background context, all lead to the conclusion that there is not. (shrink)

Is there a plausible argument for external world skepticism? Robert Nozick’s well-known discussion focuses upon arguments which utilize the Sensitivity Requirement and the Closure Principle. Nozick claims, correctly, that no such argument succeeds. But he gets almost all the details wrong. The Sensitivity Requirement and the Closure Principle are compatible; the Sensitivity Requirement is incorrect; and even if true, the Closure Principle is structurally incapable of generating a plausible and valid global skeptical argument. It is therefore a mistake to take (...) the Closure Principle as central in discussions of skepticism. The paper concludes by examining the prospects for a plausible skeptical argument. (shrink)

If p is false, it isn't evidence for anything. This view is central in one important response to a familiar sceptical argument. I consider and reject various motivations for refusing to accept this view – proposals arising from, e.g., our practice of providing rationalising explanations of people's beliefs, various locutions appearing to relativise evidence to persons, the significance of people's mental states for attributions of reasons to them, and the role of evidence in epistemic principles and requirements. I close by (...) considering responses to the ‘New Evil Demon Argument’. What emerges is an affirmation of the principle that p doesn't provide evidence unless it is true, a response to an important version of the Evil Demon argument for scepticism, and also a deeper interpretation of our epistemic practice. (shrink)

Modern-day heirs of the Cartesian revolution have been fascinated by the thought that one could utilize certain hypotheses – that one is dreaming, deceived by an evil demon, or a brain in a vat – to argue at one fell swoop that one does not know, is not justified in believing, or ought not believe most if not all of what one currently believes about the world. A good part of the interest and mystique of these discussions arises from the (...) contention that the seeds of such arguments lie in our ordinary epistemic practices, so that external world skepticism can arise “from within”. But is this contention correct? I doubt it. Taking skepticism seriously requires that we address this question head on. To do so, I will approach skeptical arguments from a certain vantage point. I will try to stand, as far as possible, with both feet squarely in ordinary life. I will start out with all of our ordinary commitments about what is the case, about what we know or have reason to believe, about when someone knows, is justified, or has good reason to believe something, and about how one should proceed in deciding what to believe. My question, then, will be this. From within that vantage point can I somehow be moved in a reasonable way to accept the conclusion that I know far less about the world around me than I thought, or that epistemically speaking, I really ought not believe much of what I have believed about the world around me? In order for such movement to take place, I will have to find reason from within my ordinary standpoint to discount or reject much of what I ordinarily accept. And of course, that reason will have to come from some.. (shrink)