Skepticism and transcendental arguments

Oxford Handbook of Philosophy of Perception, 2015

A variety of arguments for and against skepticism with respect to perception are presented and evaluated. The skeptical arguments are drawn from the Academics, the Pyrrhonists, and Descartes. Anti-skeptical responses considered include Moorean common sense, dogmatism, and externalism.

Aristotelian Society Supplementary Volume, 1998

Synthese 143 (2005), pp.273-290

Some philosophers understand epistemological skepticism as merely presenting a paradox to be solved, a paradox given rise to by some apparently forceful arguments. I argue that such a view needs to be justified, and that the best way to do so is to show that we cannot help seeing skepticism as obviously false. The obviousness (to us) of the falsity of skepticism is, I suggest, explained by the fact that we cannot live without knowledge-beliefs (a knowledge-belief about the world is a belief that a person or a group of people know that p, where p is an empirical proposition about the world). I then go on to argue for the indispensability of knowledge-beliefs. The first line of argument appeals to the practical aspects of our employment of the concept of knowledge, and the second line of argument draws on some Davidsonian ideas concerning understanding and massive agreement.

1 We focus on the visual case, leaving it to the reader to consider how the discussion generalizes to other modalities. 2 concerned how the transition from introspective beliefs to external--world beliefs could be rational. 2 In this entry, we assume without argument these positions are mistaken. We begin from the assumption that experiences (such as the one you have when you see the mustard) can justify external world beliefs about the things you see, such as beliefs that the mustard jar is in the fridge, and that the justification experience provides does not have to rely on justification for introspective beliefs. From now on, we often let it remain implicit that we are talking about external world beliefs, when we talk about the kind of beliefs that experiences justify. 3 Our main question is this: what features of experiences explain how they justify external world beliefs? The grammar of the question might suggest that experiences suffice all by themselves to provide justification for external world beliefs. But don't read this into the grammar of the phrase "experiences justify beliefs". We can distinguish between the claim that an experience can justify a belief that P, and the claim that an experience can justify a belief that P without help from other features it only contingently has. We clarify our question further in Part I, where we explain why we have chosen this point of departure, and highlight a range of theses about the role of experience in providing different types of justification. In Parts II and III, we consider the role of features of experience falling into two broad categories: constitutive features of experience, including its phenomenal character, its contents, its status as attentive or inattentive (sections 3--7); and causal features of experience such as its reliability, and the impact of other mental states on its formation (sections 8--10). Along the way, we discuss the relationships between visual experience and seeing (sections 1 and 8), and we contrast perceptual justification and perceptual knowledge (section 9).

Philosophical Studies, 2009

The traditional argument for skepticism relies on a comparison between a normal subject and a subject in a skeptical scenario: because there is no relevant difference between them, neither has knowledge. Externalists respond by arguing that there is in fact a relevant difference—the normal subject is properly situated in her environment. I argue, however, that there is another sort of comparison available—one between a normal subject and a subject with a belief that is accidentally true—that makes possible a new argument for skepticism. Unlike the traditional form of skeptical argument, this new argument applies equally well to both internalist and externalist theories of knowledge.

The philosopher David Lewis gives an account of how knowledge might be grounded in ignorance: we have knowledge only when we are unaware of those skeptical scenarios that improperly cause us to doubt. Though fascinating, this account cannot be proven. If it is correct, any attempt to examine our knowledge will only lead us into skepticism. This account lacks the anti-skeptical power which we would expect from a satisfactory theory of knowledge. The real and pressing possibility that it may be correct, however, calls into question the value of knowledge.

The skepticism I propose to discuss concerns the reality of an external world of perceivable material objects.

Such enquiries are like puzzling over the question whether we are now asleep or awake. All such questions have the same force. These people demand that a reason shall be given for everything… But their mistake is what we have stated it to be; they seek a reason for that for which no reason can be given; for the starting-point of demonstration is not demonstration. (Aristotle, Metaphysics 4.6.1011a6-13.) The supposition of this book is that we are now awake and that we are directly experiencing the real world outside us, the world within which we live and move and have our being. This world moreover, because it is directly perceived, not only exists but exists more or less the way we perceive it to exist. No serious question can arise about whether it really exists and as we perceive it to exist; the answers to such questions are immediate and immediately known; they are not inferred from anything more immediate or more known. The sort of questions instead that do arise and excite our interest and stimulate our curiosity do not concern the 'that' of the world, but the 'what' and the 'how' of it, and the 'why' and the 'wherefore' and the like. Such alone, then, are the questions that, on the basis of this supposition, it makes sense to ask and not ask. But while the supposition of the book is thus clear, it may at once seem that the supposition cannot be sustained. For it seems plain that our experience, however immediate it may appear to be, is in fact not so but is subject rather to several hallucinations and illusions, or to cases of seeming to perceive things that are not in fact there or of seeming to perceive things that, even if there, are not there as they are perceived to be. Illusions is the word often used to refer, as it were, to piecemeal errors, errors that call into question particular senses on particular