Online research in philosophy

General introduction -- What is knowledge? -- What is the value of knowledge? -- What evidence do we have? -- How should we distribute our confidence? -- What is it to be justified in believing something? -- What is the structure of justification and knowledge? -- What is the nature of the epistemic 'ought'? -- What are the sources of knowledge? -- What can we know? -- Is knowledge in the eye of the beholder?

It is an intuitively attractive view that the importance of a proposition affects the amount of evidence a subject needs in order to know that proposition—the more important the proposition is to the subject, the more evidence the subject must have in order for her to count as knowing the proposition. This paper argues that because unimportant propositions entail the falsity of very important propositions this position either results in the lack of closure of knowledge under known implication, or it results in standards for evidence being universally high.

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.

theory of knowledge defended in Timothy Williamson's book Knowledge and its Limits is compared here with the theory defended in the author's articles ‘How Knowledge Works’ and ‘Knowledge and Self-Knowledge’. It is argued that there are affinities between these theories, but that the latter has considerably more explanatory power.

Timothy Williamson has argued that a person S ’s total evidence is constituted solely by propositions that S knows. This theory of evidence entails that a false belief can not be a part of S ’s evidence base for a conclusion. I argue by counterexample that this thesis (E = K for now) forces an implausible separation between what it means for a belief to be justified and rational from one’s perspective and what it means to base one’s beliefs on the evidence. Furthermore, I argue that E = K entails the implausible result that there are cases in which a well-evidenced belief necessarily can not serve as evidence for a further proposition.

If we add as an extra premise that the agent does know H, then it is possible for her to know E — H, we get the conclusion that the agent does not really know H. But even without that closure premise, or something like it, the conclusion seems quite dramatic. One possible response to the argument, floated by both Descartes and Hume, is to accept the conclusion and embrace scepticism. We cannot know anything that goes beyond our evidence, so we do not know very much at all. This is a remarkably sceptical conclusion, so we should resist it if at all possible. A more modern response, associated with externalists like John McDowell and Timothy Williamson, is to accept the conclusion but deny it is as sceptical as it first appears. The Humean argument, even if it works, only shows that our evidence and our knowledge are more closely linked than we might have thought. Perhaps that’s true because we have a lot of evidence, not because we have very little knowledge. There’s something right about this response I think. We have more evidence than Descartes or Hume thought we had. But I think we still need the idea of ampliative knowledge. It stretches the concept of evidence to breaking point to suggest that all of our knowledge, including knowledge about the future, is part of our evidence. So the conclusion really is unacceptable. Or, at least, I think we should try to see what an epistemology that rejects the conclusion looks like.

Sherrilyn Roush defends a new theory of knowledge and evidence, based on the idea of "tracking" the truth, as the best approach to a wide range of questions about knowledge-related phenomena. The theory explains, for example, why scepticism is frustrating, why knowledge is power, and why better evidence makes you more likely to have knowledge. Tracking Truth provides a unification of the concepts of knowledge and evidence, and argues against traditional epistemological realist and anti-realist positions about scientific theories and for a piecemeal approach based on a criterion of evidence, a position Roush calls "real anti-realism." Epistemologists and philosophers of science will recognize this as a significant original contribution.

The definition of memory knowledge that p put forward in this paper is nontraditional in that the justification for the belief that p which constitutes that knowledge is not located in any memory-impression or other present state of the subject. Rather it is the subject's actual past justification for p, or a proper part thereof, that justifies this present belief that p. It is argued (1) that the notion under definition is that of knowing straight from memory, (2) that an adequate definition here must take into account a difference, as to conflicting evidence one does not possess, between evidence one has forgotten and evidence one has never had, (3) that compared to Ginet's traditional definition (1975), the definition has several advantages, and (4) that the definition handles at least one type of situation where there can be memory knowledge that p without previous knowledge that p.

What is the nature of the evidence provided by thought experiments in philosophy? For instance, what evidence is provided by the Gettier thought experiment against the JTB theory of knowledge? According to one view, it provides as evidence only a certain psychological proposition, e.g. that it seems to one that the subject in the Gettier case lacks knowledge. On an alternative, nonpsychological view, the Gettier thought experiment provides as evidence the nonpsychological proposition that the subject in the Gettier case lacks knowledge (e.g., Williamson 2007). Given the centrality of thought experiments to philosophical enquiry, the correct account of thought experiment evidence is important for understanding the nature of philosophical methodology. Further, Williamson argues that a misguided adherence to the psychological view of thought experiment evidence encourages scepticism about philosophy since it opens a gap between our evidence and the nonpsychological subject matter of philosophy. The main aim of this paper is to defend the psychological view against recent objections. In particular, I argue that even if thought experiment evidence is psychological, it can still provide justification for non-psychological claims which are the subject matter of philosophy.

According to Williamson, your evidence consists of all and only what you know (E = K). According to his critics, it doesn’t. While E = K calls for revision, the revisions it calls for are minor. E = K gets this much right. Only true propositions can constitute evidence and anything you know non-inferentially is part of your evidence. In this paper, I defend these two theses about evidence and its possession from Williamson’s critics who think we should break more radically from E = K.