Jonathan L. Kvanvig

This chapter explores the different grounds for accepting the claim that all truths are knowable, the assumption central to the derivation of Fitch’s result. It argues that although there is no compelling argument for holding that all truths are knowable, there are various positions in which this feature of semantic anti-realism fits naturally; rejecting this puts serious tension into a broad range of philosophical outlooks, including theism and physicalism. In the end, the paradox should be felt by everyone, even those who do not accept the knowability claim, because the heart of the paradox is not simply in what is implied by the knowability claim, but in a lost logical distinction between what is actual and what is possible.

This chapter examines the logical structure of the knowability paradox, presenting the details of the proofs that underlie the paradox, and clarifying which elements of these proofs give rise to paradox. It argues that there is no simple and obvious logical mistake in the derivation of the knowability result. A paradox has deep significance only if it arises from plausible premises. Those in question in Fitch’s proof are the claim of epistemic modesty, that some truths will never be known, and the knowability principle that all truths are knowable. Although the second claim does not have the same intuitive pull as the first, there are substantive grounds in its favour; grounds that some hold show that all truths are knowable, but which show at the very least that it is plausible to maintain that all truths are knowable.

Ernest Sosa's latest epistemology remains a version of virtue epistemology, and I argue here that it faces two central problems, pressing a point I have made elsewhere, that virtue epistemology does not present a complete answer to the problem of the value of knowledge. I will press this point regarding the nature of knowledge through variations on two standard Gettier examples here. The first is the Fake Barn case and the second is the Tom Grabit case. I will argue that Sosa's latest virtue epistemology fails to handle either case acceptably, and that as a result, cannot explain the value that knowledge has over that of the sum of any of its proper subparts. La última epistemología de Ernest Sosa continúa siendo una versión de epistemología de las virtudes, y siguiendo con una idea que ya planteé en otra parte, aquí argumento que afronta dos problemas centrales: que la epistemología de las virtudes no presenta una respuesta completa al problema del valor del conocimiento. Insistiré en esta idea sobre la naturaleza del conocimiento mediante variaciones de dos ejemplos estándares tipo Gettier. El primero es el caso del granero falso y el segundo es el caso de Tom Grabit. Argumentaré que la última epistemología de las virtudes de Sosa no maneja ninguno de estos casos de forma aceptable, y en consecuencia no puede explicar el valor que tiene el conocimiento por encima del de la suma de cualesquiera de sus propias partes.

This chapter explores the challenge to the proof of Fitch’s results presented by intuitionism, and the prospects of this viewpoint in avoiding the paradox that results. It argues that adopting intuitionistic principles of reasoning will not help avoid the paradox. It merely changes what is paradoxical from a lost distinction between known truth and knowable truth, to a lost distinction between unknown truth and unknowable truth. Since paradox remains in both cases, the solution to the paradox must be found elsewhere.

Motivated by Plantinga's work, fourteen prominent philosophers have written new essays investigating Plantingian warrant and its contribution to contemporary epistemology. The resulting collection, representing a broad array of views, not only gives readers a critical perspective on Plantinga's landmark work, but also provides in one volume a clear statement of the variety of approaches to the nature of warrant within contemporary epistemology and to the connections between epistemology and metaphysics.

The knowability paradox derives from a proof by Frederic Fitch in 1963. The proof purportedly shows that if all truths are knowable, it follows that all truths are known. Antirealists, wed as they are to the idea that truth is epistemic, feel threatened by the proof. For what better way to express the epistemic character of truth than to insist that all truths are knowable? Yet, if that insistence logically compels similar assent to some omniscience claim, antirealism is in jeopardy. Response to the paradox has drifted toward a common theme, a theme I will argue is a non-starter in resolving the paradox. Seeing this point will also make clear the philosophical inadequacy of simply viewing the paradox as a refutation of a wide range of antirealisms.

Duncan Pritchard’s book (Epistemic Luck, Oxford University Press, 2005) concerns the interplay between two disturbing kinds of epistemic luck, termed “reflective” and “veritic,” and two types of arguments for skepticism, one based on a closure principle for knowledge and the other on an underdetermination thesis about the quality of our evidence for the everyday propositions we believe. Pritchard defends the view that a safety-based account of knowledge can answer the closure argument and provide an account of how veritic epistemic luck is eliminated. He also argues that reflective epistemic luck cannot be eliminated, and that even though it is the sort of luck with which the underdetermination argument is concerned, the fact that this type of luck cannot be eliminated doesn’t undermine knowledge. Instead, it undermines the assertibility of our knowledge, at least in skeptical contexts. So when the skeptic challenges the idea that we know using the underdetermination principle, we have no legitimate response to offer, and it is this fundamental fact of epistemic life that Pritchard terms our inevitable epistemic angst.