Timothy Williamson's epistemology leads to a fairly radical version of scepticism. According to him, all knowledge is evidence. It follows that if S knows p, the evidential probability for S that p is 1. I explain Williamson's infallibilist account of perceptual knowledge, contrasting it with Peter Klein's, and argue that Klein's account leads to a certain problem which Williamson's can avoid. Williamson can allow that perceptual knowledge is possible and that all knowledge is evidence, while at the same time avoiding (...) Klein's problem. But while Williamson can allow that we know some things through experience, there are very many things he must say we cannot know. Given just how very many these are, he should be considered a sceptic. (shrink)

I set out the standard view about alleged examples of failure of transmission of warrant, respond to two cases for the view, and argue that the view is false. The first argument for the view neglects the distinction between believing a proposition on the basis of a justification and merely having a justification to believe a proposition. The second argument for the view neglects the position that one's justification for believing a conclusion can be one's premise for the conclusion, rather (...) than simply one's justification for the premise. Finally, the view is false since it is inconsistent with the closure of knowledge as closure is properly understood. (shrink)

In this paper, I consider some issues involving a certain closure principle for Structural Justification, a relation between a cognitive subject and a proposition that’s expressed by locutions like ‘S has a source of justification for p’ and ‘p is justifiable for S’. I begin by summarizing recent work by Peter Klein that advances the thesis that the indicated closure principle is plausible but lacks Skeptical utility. I then assess objections to Klein’s thesis based on work by Robert Audi and (...) Anthony Brueckner. One finding is that the typical statement of the relevant closure principle can express a number of different closure principles, and that recognizing this helps to resolve certain disputes. (shrink)

It is argued, on the basis of new counterexamples, that neither knowledge nor epistemic justification (or “epistemic rationality”) can reasonably be thought to be closed under logical implication. The argument includes an attempt to reconcile the fundamental intuitions of the opposing parties in the debate.

: This paper is about the nature of practical reasons. More specifically, my primary goal is to explore when an agent has a justifying reason for action¾that is, a reason that can be used for justifying an action that has been done or that the agent is planning to do. This concept of reason is central to ethics and to practical philosophy in general. I defend an account of reason according to which a piece of practical reasoning gives an agent (...) a reason for action if he has a reason for its premises and a warrant for holding that these premises logically support the conclusion. That is roughly to say that justifying reasons are closed under logical entailment. To achieve this aim, I shall discuss the components of such reasons. Section 2 presents a principle of closure for justifying reasons and clarifies two important clauses of this principle. In the last section, I show how my account can sidestep the regress problem in practical reasoning. (shrink)

E. J. Coffman defends Peter Klein’s work on epistemic closure against various objections that I raised in an earlier paper. In this paper, I respond to Coffman.

It is argued, on the basis of new counterexamples, that neither knowledge nor epistemic justification (or epistemic rationality ) can reasonably be thought to be closed under logical implication. The argument includes an attempt to reconcile the fundamental intuitions of the opposing parties in the debate.

The paper discusses the relations between two putative epistemic principles, Reflexivity and Closure, with a view to assess whether the repudiation of the former, usually required by externalistic accounts of knowledge, necessitates the repudiation, as well, of the latter. A negative reply to that question is offered, which prompts the hypothesis that alleged counterexamples to Closure are artifacts of the rather peculiar conditions on which, in the course of a particular kind of epistemological inquiry, are introduced assumptions such as are (...) characteristic of the methodological use of so-called skeptical “doubts”. (shrink)