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)

Some evidential arguments from evil rely on an inference of the following sort: 'If, after thinking hard, we can't think of any God-justifying reason for permitting some horrific evil then it is likely that there is no such reason'. Sceptical theists, us included, say that this inference is not a good one and that evidential arguments from evil that depend on it are, as a result, unsound. Michael Almeida and Graham Oppy have argued (in a previous issue of this journal) (...) that Michael Bergmann's way of developing the sceptical theist response to such arguments fails because it commits those who endorse it to a sort of scepticism that undermines ordinary moral practice. In this paper, we defend Bergmann's sceptical theist response against this charge. (shrink)

In this paper, the author defends Peter van Inwagen’s modal skepticism. Van Inwagen accepts that we have much basic, everyday modal knowledge, but denies that we have the capacity to justify philosophically interesting modal claims that are far removed from this basic knowledge. The author also defends the argument by means of which van Inwagen supports his modal skepticism, offering a rebuttal to an objection along the lines of that proposed by Geirrson. Van Inwagen argues that Stephen Yablo’s recent and (...) influential account of the relationship between conceivability and possibility supports his skeptical claims. The author’s defence involves a creative interpretation and development of Yablo’s account, which results in a recursive account of modal epistemology, what the author calls the “safe explanation” theory of modal epistemology. (shrink)

Excerpts from Robert Nozick's "Invariances" Necessary truths are invariant across all possible worlds, contingent ones across only some.

In recent years skeptical theism has gained currency amongst theists as a way to escape the problem of evil by invoking putatively reasonable skepticism concerning our ability to know that instances of apparently gratuitous evil are unredeemed by morally sufficient reasons known to God alone. After explicating skeptical theism through the work of Stephen Wykstra and William Alston, I present a cumulative-case argument designed to show that skeptical theism cannot be accepted by theists insofar as it crucially undermines epistemic license (...) to the very theism it is invoked to defend. I also argue that attempts to defend a theism-friendly moderate version of skeptical theism either fail to halt the spread of damaging skepticism, or lack philosophical validity. (shrink)

Skeptical theism seeks to defend theism against the problem of evil by invoking putatively reasonable skepticism concerning human epistemic limitations in order to establish that we have no epistemological basis from which to judge that apparently gratuitous evils are not in fact justified by morally sufficient reasons beyond our ken. This paper contributes to the set of distinctively practical criticisms of skeptical theism by arguing that religious believers who accept skeptical theism and take its practical implications seriously will be forced (...) into a position of paralysis or "aporia" when faced with a wide set of morally significant situations. It is argued that this consequence speaks strongly against the acceptance of skeptical theism insofar as such moral "aporia" is inconsistent with religious moral teaching and practice. In addition, a variety of arguments designed to show that accepting skeptical theism does not lead to this consequence are considered, and shown to be deficient. (shrink)

I formulate and defend two sceptical theses on specific parts of our modal knowledge (unqualified and absolute modalities). My main point is that unqualified modal sentences are defective in that they fail to belong unambiguously to specific modal kinds and thus cannot be evaluated; hence, we must be sceptical of beliefs involving them.

I argue that if a subject's acquaintance with an object is necessary for him to think about and refer to the object, then the content of his thought cannot be a set of metaphysically possible worlds. Acquaintance resets what possibilities there are; it affects the powers of representation, and does not only limit the range of possibilities. If acquaintance restricts what a subject can think about, the theorist cannot specify what possibilities are open to the subject simply in terms of (...) possible worlds. (shrink)

Abstract Timothy Williamson has recently proposed to undermine modal skepticism by appealing to the reducibility of modal to counterfactual logic ( Reducibility ). Central to Williamson’s strategy is the claim that use of the same non-deductive mode of inference ( counterfactual development , or CD ) whereby we typically arrive at knowledge of counterfactuals suffices for arriving at knowledge of metaphysical necessity via Reducibility. Granting Reducibility, I ask whether the use of CD plays any essential role in a Reducibility-based reply (...) to two kinds of modal skepticism. I argue that its use is entirely dispensable, and that Reducibility makes available replies to modal skeptics which show certain propositions to be metaphysically necessary by deductive arguments from premises the modal skeptic accepts can be known. Content Type Journal Article Pages 1-19 DOI 10.1007/s11098-011-9784-4 Authors Juhani Yli-Vakkuri, Wolfson College, Oxford University, Oxford, OX2 6UD UK Journal Philosophical Studies Online ISSN 1573-0883 Print ISSN 0031-8116. (shrink)