Timothy Williamson has fruitfully exploited formal resources to shed considerable light on the nature of knowledge. In the paper under examination, Williamson turns his attention to Gettier cases, showing how they can be motivated formally. At the same time, he disparages the kind of justification he thinks gives rise to these cases. He favors instead his own notion of justification for which Gettier cases cannot arise. We take issue both with his disparagement of the kind of justification that figures in (...) Gettier cases and the specifics of the formal motivation. (shrink)

I argue that epistemologists’ use of the term ‘epistemic’ has led to serious confusion in the discussion of epistemological issues. The source of the problem is that ‘epistemic’ functions largely as an undefined technical term. I show how this confusion has infected discussions of the nature of epistemic justification, epistemic norms for evidence gathering, and knowledge norms for assertion and belief.

Knowledge and its Limits presents a systematic new conception of knowledge as a kind of mental stage sensitive to the knower's environment. It makes a major contribution to the debate between externalist and internalist philosophies of mind, and breaks radically with the epistemological tradition of analyzing knowledge in terms of true belief. The theory casts new light on such philosophical problems as scepticism, evidence, probability and assertion, realism and anti-realism, and the limits of what can be known. The arguments are (...) illustrated by rigorous models based on epistemic logic and probability theory. The result is a new way of doing epistemology and a notable contribution to the philosophy of mind. (shrink)

The five commentators on my paper ‘Gettier Cases in Epistemic Logic’ (GCEL) demonstrate how fruitful the topic can be. Especially in Brian Weatherson's contribution, and to some extent in those of Jennifer Nagel and Jeremy Goodman, much of the material constitutes valuable development and refinement of ideas in GCEL, rather than criticism. In response, I draw some threads together, and answer objections, mainly those in the papers by Stewart Cohen and Juan Comesaña and by Goodman.

The possibility of justified true belief without knowledge is normally motivated by informally classified examples. This paper shows that it can also be motivated more formally, by a natural class of epistemic models in which both knowledge and justified belief are represented. The models involve a distinction between appearance and reality. Gettier cases arise because the agent's ignorance increases as the gap between appearance and reality widens. The models also exhibit an epistemic asymmetry between good and bad cases that sceptics (...) seem to ignore or deny. (shrink)

The possibility of justified true belief without knowledge is normally motivated by informally classified examples. This paper shows that it can also be motivated more formally, by a natural class of epistemic models in which both knowledge and justified belief (in the relevant sense) are represented. The models involve a distinction between appearance and reality. Gettier cases arise because the agent's ignorance increases as the gap between appearance and reality widens. The models also exhibit an epistemic asymmetry between good and (...) bad cases that sceptics seem to ignore or deny. (shrink)

Recently, Timothy Williamson has argued that considerations about margins of errors can generate a new class of cases where agents have justified true beliefs without knowledge. I think this is a great argument, and it has a number of interesting philosophical conclusions. In this note I’m going to go over the assumptions of Williamson’s argument. I’m going to argue that the assumptions which generate the justification without knowledge are true. I’m then going to go over some of the recent arguments (...) in epistemology that are refuted by Williamson’s work. And I’m going to end with an admittedly inconclusive discussion of what we can know when using an imperfect measuring device. (shrink)

The idea that knowledge can be extended by inference from what is known seems highly plausible. Yet, as shown by familiar preface paradox and lottery-type cases, the possibility of aggregating uncertainty casts doubt on its tenability. We show that these considerations go much further than previously recognized and significantly restrict the kinds of closure ordinary theories of knowledge can endorse. Meeting the challenge of uncertainty aggregation requires either the restriction of knowledge-extending inferences to single premises, or eliminating epistemic uncertainty in (...) known premises. The first strategy, while effective, retains little of the original idea—conclusions even of modus ponens inferences from known premises are not always known. We then look at the second strategy, inspecting the most elaborate and promising attempt to secure the epistemic role of basic inferences, namely Timothy Williamson’s safety theory of knowledge. We argue that while it indeed has the merit of allowing basic inferences such as modus ponens to extend knowledge, Williamson’s theory faces formidable difficulties. These difficulties, moreover, arise from the very feature responsible for its virtue- the infallibilism of knowledge. (shrink)

What is it to have a reason? According to one common idea, the "Factoring Account", you have a reason to do A when there is a reason for you to do A which you have--which is somehow in your possession or grasp. In this paper, I argue that this common idea is false. But though my arguments are based on the practical case, the implications of this are likely to be greatest in epistemology: for the pitfalls we fall into when (...) trying to defend the Factoring Account reflect very well the major developments in empiricist epistemology during the 20th century. I conjecture that this is because epistemologists have been--wrongly--wedded to the Factoring Account about evidence, which I conjecture is a certain kind of reason to believe. (shrink)

Most of us, tacitly or explicitly, embrace a more or less Cartesian conception of our epistemic condition. According to such a conception, "what we have to go on" in learning about the world is, on the one hand, that which is a priori accessible to us, and, on the other, the inner experiences - visual imagery, tactile sensations, recollective episodes and so on - that pop into our Carte- sian theaters. One of the central themes of Knowledge and its Limits (...) is that this picture is fundamentally wrong. Williamson suggests that we should embrace the thesis that our body of evidence at a given time is all and only that which we know. Call this the "E=K thesis." If the E=K thesis is correct, then what we have to go on is both more and less than the Cartesian picture would suggest: more because its domain extends outwards in space, and for- wards and backwards in time; less because that which is unknown about our experiential life is excluded. In what follows, I shall identify and briefly discuss a number of themes connected to the E=K thesis. (shrink)

Most of us, tacitly or explicitly, embrace a more or less Cartesian conception of our epistemic condition. According to such a conception, “what we have to go on”in learning about the world is, on the one hand, that which is a priori accessible to us, and, on the other, the inner experiences—visual imagery, tactile sensations, recollective episodes and so on—that pop into our Cartesian theaters. One of the central themes of Knowledge and its Limits is that this picture is fundamentally (...) wrong. Williamson suggests that we should embrace the thesis that our body of evidence at a given time is all and only that which we know. Call this the “E=K thesis.”If the E=K thesis is correct, then what we have to go on is both more and less than the Cartesian picture would suggest: more because its domain extends outwards in space, and forwards and backwards in time; less because that which is unknown about our experiential life is excluded. In what follows, I shall identify and briefly discuss a number of themes connected to the E=K thesis. (shrink)

Perhaps the concept of knowledge, prior to its being fashioned and molded by certain philosophical traditions, never offered any stable negative verdict in the original fake barn case.

An argument that takes issue with the contemporary epistemological consensus that justification is distinct from knowledge, proposing instead that justified belief simply is knowledge, and arguing in detail that a belief is justified when ...