In this article I investigate a neglected form of radical skepticism that questions whether any of our logical, mathematical and other seemingly self-evident beliefs count as knowledge. ‘A priori skepticism,’ as I will call it, challenges our ability to know any of the following sorts of propositions: (1.1) The sum of two and three is five. (1.2) Whatever is square is rectangular. (1.3) Whatever is red is colored. (1.4) No surface can be uniformly red and uniformly blue (...) at the same time. (1.5) If ‘if p then q’ is true and ‘p’ is true, then ‘q’ is true. (1.6) No statement can be both true and false at the same time and in the same respect. (1.7) If A is taller than B, and B is taller than C, then A is taller than C. (1.8) Everything is identical to itself. (1.9) If the conclusion of an inductive argument is contingent, it is possible for the premises of that argument to be true and its conclusion to be false. (1.10) George W. Bush could have been a plumber. (1.11) George W. Bush could not have been a prime number. (1.12) ‘2 + 3 = 5’ is necessarily true. (shrink)

_ Source: _Page Count 12 In a previous article, I argued against the widespread reluctance of philosophers to treat skeptical challenges to our a priori knowledge of necessary truths with the same seriousness as skeptical challenges to our a posteriori knowledge of contingent truths. Hamid Vahid has recently offered several reasons for thinking the unequal treatment of these two kinds of skepticism is justified, one of which is a priori skepticism’s seeming dependence upon the widely scorned (...) kk thesis. In the present article, I defend a priori skepticism against Vahid’s criticisms. (shrink)

I reconstruct and critique two arguments Laurence BonJour has recently offered against skepticism about the a priori. While the arguments may provide anti-skeptical, internalist foundationalists with reason to accept the a priori, I show that neither argument provides sufficient reason for believing the more general conclusion that there is no rational alternative to accepting the a priori.

This paper contains replies to comments on the author's paper "A Priori Knowledge and the Scope of Philosophy." Several points in the argument of that paper are given further clarification: the notion of our standard justificatory procedure, the notion of a basic source of evidence, and the doctrine of modal reliabilism. The reliability of intuition is then defended against Lycan's skepticism and a response is given to Lycan's claim that the scope of a priori knowledge does not (...) include philosophically central topics such as the nature of consciousness. Next a counterfactual account of intuitions proposed by Sosa is criticized. Finally, in response to certain questions raised by Sosa, the explanation of the evidential status of intuition offered in the original paper receives further elaboration. (shrink)

In this paper, we present a dialectical argument for a priori skepticism (i.e. the thesis that we can be skeptical about a priori knowledge). Then, we propose a framework that combines elements from inferential contextualism and logical conventionalism to offer a weak transcendental argument against a priori skepticism.

Jeffrey Friedman has attempted to make a case for limiting state social engineering that is based on the skeptical epistemology of Sir Karl Popper. But Popper's epistemology is flawed, both in its rejection of a priori theorizing and its insistence on empirical falsification rather than confirmation. Classical liberalism of the sort that Friedman advocates requires, as its basis, positive knowledge of economics and social reality—not Popperian skepticism.

Hillary Putnam has famously argued that we can know that we are not brains in a vat because the hypothesis that we are is self-refuting. While Putnam's argument has generated interest primarily as a novel response to skepticism, his original use of the brain in a vat scenario was meant to illustrate a point about the "mind/world relationship." In particular, he intended it to be part of an argument against the coherence of metaphysical realism, and thus to be part (...) of a defense of his conception of truth as idealized rational acceptability. Putnam's conclusions about the scenario are, however, actually out of line with central and plausible aspects of his own account of the relationship between our minds and the world. Reflections on semantics give us no compelling reason to suppose that claims like "I am a brain in a vat" could not turn out to be true. (shrink)

I argue in favor of the possibility of real a priori justification. Some writers have claimed that, to adequately defend against the naturalist, we should grant that a priori justification can be defeated by further experiential evidence. Such writers generally view a priori faculties as on a par with empirical faculties but with different proper objects. While perceptual objects are the contingently existing things with which we are in causal contact, a priori objects are either necessarily (...) true propositions or necessarily existing abstract objects with which we are not in causal contact. ;Though I admit that there is a weak sense of a priori justification according to which an a priori justified belief can become irrational in the face of experiential evidence, I argue that genuine a priori justification cannot be overridden by further experiential considerations . Allowing that a priori justification admits of degrees, we can be more or less a priori justified in a belief, depending on the extent to which that belief is revisable in the face of experiential evidence. In this way, I argue that the naturalist, in saying that a priori justification can always be defeated by experiential evidence, does not impugn the possibility that some beliefs can have a greater degree of a priori justification than others . I further argue that experiential beliefs derive much of their justification from a large background network of beliefs with a high degree of a priori justification. Some inference rules, I argue, in licensing the revision of empirical beliefs, must be unrevisable in their own right. Thus, if the naturalist is right, and a priori justification does require mysterious, occult processes, then so does experiential justification. If mysterious, occult processes are to be avoided at all costs, naturalism commits us to a rather extreme form of philosophical skepticism. (shrink)

Joel Pust has recently challenged the Thomas Reid-inspired argument against the reliability of the a priori defended by Alvin Plantinga, Nicholas Wolterstorff, William Alston, and Michael Bergmann. The Reidian argument alleges that the Cartesian insistence on the primacy of a priori rationality and subjective sensory experience as the foundations of epistemic justification is unwarranted because the same kind of global skeptical scenario that Cartesians recognize as challenging the legitimacy of perceptual beliefs about the external world also undermine the (...) reliability of a priori rationality. In reply, Pust contends that some a priori propositions are beyond doubt and that fact can be used to support the overall reliability of reason. This paper challenges Pust’s argument. I argue that while Pust successfully undermines a radical skeptical view of reason, he does not refute a more modest skepticism. I conclude with some suggestions for Cartesian a priorists. (shrink)

SummaryA familiar sort of argument for skepticism about the external world appeals to the evidential similarity between what is presumed to be the normal case and the case where one is a brain in a vat . An argument from Putnam has been taken by many to provide an a priori refutation of this sort of skeptical argument. The question I propose to address in this paper is whether Putnam's argument affords us an a priori refutation of (...) skeptical arguments that appeal to the claim that one does not know that one is not a BIV. I will develop a negative answer to this question along two related fronts. Along the first front I defend against new criticisms the common position that the externalism on which Putnam's argument is based entails skepticism about the meanings of sentences in our language and the contents of our thoughts. I do not take this to be a refutation of externalism or externalist arguments; rather, I see this as a motivation to locate the difficulty with arguments for externalism. But if externalism is abandoned, of course, the anti‐skeptical argument it has widely been taken to support must be abandoned along with it. I will argue, however, that this is not a significant loss, because along a second front I will argue that externalism cannot be given a priori justification; it is therefore ill‐suited to ground an a priori refutation of BIV skepticism anyway. (shrink)

SummaryA familiar sort of argument for skepticism about the external world appeals to the evidential similarity between what is presumed to be the normal case and the case where one is a brain in a vat. An argument from Putnam has been taken by many to provide an a priori refutation of this sort of skeptical argument. The question I propose to address in this paper is whether Putnam's argument affords us an a priori refutation of skeptical (...) arguments that appeal to the claim that one does not know that one is not a BIV. I will develop a negative answer to this question along two related fronts. Along the first front I defend against new criticisms the common position that the externalism on which Putnam's argument is based entails skepticism about the meanings of sentences in our language and the contents of our thoughts. I do not take this to be a refutation of externalism or externalist arguments; rather, I see this as a motivation to locate the difficulty with arguments for externalism. But if externalism is abandoned, of course, the anti‐skeptical argument it has widely been taken to support must be abandoned along with it. I will argue, however, that this is not a significant loss, because along a second front I will argue that externalism cannot be given a priori justification; it is therefore ill‐suited to ground an a priori refutation of BIV skepticism anyway. (shrink)

Recently, new life has been breathed into the ancient philosophical topic of skepticism. The subject of some of the best and most provocative work in contemporary philosophy, skepticism has been addressed not only by top epistemologists but also by several of the world's finest philosophers who are most known for their work in other areas of the discipline. Skepticism: A Contemporary Reader brings together the most important recent contributions to the discussion of skepticism. Covering major approaches (...) to the skeptical problem, it features essays by Anthony Brueckner, Keith DeRose, Fred Dretske, Graeme Forbes, Christopher Hill, David Lewis, Thomas Nagel, Robert Nozick, Hilary Putnam, Ernest Sosa, Gail Stine, Barry Stroud, Peter Unger, and Ted Warfield. The book opens with a thorough introduction that outlines the skeptical problem, explains the dominant responses to skepticism, and discusses the strengths, weaknesses, and unresolved issues of each response, providing undergraduate students and nonphilosophers with the background and context necessary to understand the essays. Skepticism: A Contemporary Reader serves as an ideal text for courses in epistemology and skepticism and will also appeal to professional philosophers and interested general readers. (shrink)

The Human A Priori is a collection of essays by A. W. Moore, one of them previously unpublished and the rest all revised. These essays are all concerned, more or less directly, with something ineliminably anthropocentric in our systematic pursuit of a priori sense-making. Part I deals with the nature, scope, and limits of a priori sense-making in general. Parts II, III, and IV deal with what are often thought to be the three great exemplars of the (...) systematic pursuit of such sense-making: philosophy in the case of Part II, ethics in the case of Part III, and mathematics in the case of Part IV. Much of the attention throughout is devoted to the work of other philosophers: Kant and Wittgenstein feature prominently, and five of the essays take the form of reviews or critical notices of recent work in philosophy. But the interest in never purely exegetical. One of the lessons that emerges from the essays, either in opposition to the views of these other philosophers or by invocation of their views, is that we humans achieve nothing of real significance in philosophy, ethics, or mathematics except from a human point of view, and hence that all three of these pursuits can be said to betoken what may reasonably be called 'the human a priori'. (shrink)

O objetivo deste artigo foi compreender como o Estado se apropriou de dispositivos legais para legitimar as suas ações punitivas e jurídicas contra a oposição política, em especial, os militantes do Partido Comunista Brasileiro no Paraná em 1975, quando foram presos e indiciados pelo Inquérito Policial-Militar 745, que apurou o envolvimento dos comunistas na suposta reorganização do partido no Estado. Além do IPM, também utilizamos como fonte de pesquisa o Relatório Especial de Informações 1/75 que destacou a importância dos trabalhos (...) da polícia política efetuados no Estado, a fim de conter o avanço do comunismo. (shrink)