This book presents an original discussion and analysis of epistemic peer disagreement. It reviews a wide range of cases from the literature, and extends the definition of epistemic peerhood with respect to the current one, to account for the actual variability found in real-world examples. The book offers a number of arguments supporting the variability in the nature and in the range of disagreements, and outlines the main benefits of disagreement among peers i.e. what the author calls the benefits to (...) inquiry argument. (shrink)

I argue elsewhere (Roche 2014) that evidence of evidence is evidence under screening-off. Tal and Comesaña (2017) argue that my appeal to screening-off is subject to two objections. They then propose an evidence of evidence thesis involving the notion of a defeater. There is much to learn from their very careful discussion. I argue, though, that their objections fail and that their evidence of evidence thesis is open to counterexample.

We examine whether the "evidence of evidence is evidence" principle is true. We distinguish several different versions of the principle and evaluate recent attacks on some of those versions. We argue that, whatever the merits of those attacks, they leave the more important rendition of the principle untouched. That version is, however, also subject to new kinds of counterexamples. We end by suggesting how to formulate a better version of the principle that takes into account those new counterexamples.

Is evidential support transitive? The answer is negative when evidential support is understood as confirmation so that X evidentially supports Y if and only if p(Y | X) > p(Y). I call evidential support so understood “support” (for short) and set out three alternative ways of understanding evidential support: support-t (support plus a sufficiently high probability), support-t* (support plus a substantial degree of support), and support-tt* (support plus both a sufficiently high probability and a substantial degree of support). I also (...) set out two screening-off conditions (under which support is transitive): SOC1 and SOC2. It has already been shown that support-t is non-transitive in the general case (where it is not required that SOC1 holds and it is not required that SOC2 holds), in the special case where SOC1 holds, and in the special case where SOC2 holds. I introduce two rather weak adequacy conditions on support measures and argue that on any support measure meeting those conditions it follows that neither support-t* nor support-tt* is transitive in the general case, in the special case where SOC1 holds, or in the special case where SOC2 holds. I then relate some of the results to Douven’s evidential support theory of conditionals along with a few rival theories. (shrink)

There are many scientific and everyday cases where each of Pr and Pr is high and it seems that Pr is high. But high probability is not transitive and so it might be in such cases that each of Pr and Pr is high and in fact Pr is not high. There is no issue in the special case where the following condition, which I call “C1”, holds: H 1 entails H 2. This condition is sufficient for transitivity in high (...) probability. But many of the scientific and everyday cases referred to above are cases where it is not the case that H 1 entails H 2. I consider whether there are additional conditions sufficient for transitivity in high probability. I consider three candidate conditions. I call them “C2”, “C3”, and “C2&3”. I argue that C2&3, but neither C2 nor C3, is sufficient for transitivity in high probability. I then set out some further results and relate the discussion to the Bayesian requirement of coherence. (shrink)

John Hardwig has championed the thesis (NE) that evidence that an expert EXP has evidence for a proposition P, constituted by EXP’s testimony that P, is not evidence for P itself, where evidence for P is generally characterized as anything that counts towards establishing the truth of P. In this paper, I first show that (NE) yields tensions within Hardwig’s overall view of epistemic reliance on experts and makes it imply unpalatable consequences. Then, I use Shogenji-Roche’s theorem of transitivity of (...) incremental confirmation to show that (NE) is false if a natural Bayesian formalization of the above notion of evidence is implemented. I concede that Hardwig could resist my Bayesian objection if he re-interpreted (NE) as a more precise thesis that only applies to community-focused evidence. I argue, however, that this precisification, while diminishing the philosophical relevance of (NE), wouldn’t settle the tensions internal to Hardwig’s views. (shrink)

We offer a critical evaluation of a recent proposal of E. Tal and J. Comesa\~na on the topic of when evidence of evidence constitutes evidence. After establishing that attempts of L. Moretti and W. Roche to discredit the proposal miss their mark, we fashion another, which does not.

Sometimes a proposition is ‘opaque’ to an agent: he doesn't know it, but he does know something about how coming to know it should affect his or her credence function. It is tempting to assume that a rational agent's credence function coheres in a certain way with his or her knowledge of these opaque propositions, and I call this the ‘Opaque Proposition Principle’. The principle is compelling but demonstrably false. I explain this incongruity by showing that the principle is ambiguous: (...) the term ‘know’ as it appears in the principle can be interpreted in two different ways, as either basic-know or super-know. I use this distinction to construct a plausible version of the principle, and then to similarly construct plausible versions of the Reflection Principle and the Sure-Thing Principle. (shrink)

Some philosophers argue that non-presentist A-theories problematically imply that we cannot know that this moment is present. The problem is usually presented as arising from the combination of the A-theoretic ideology of a privileged presentness and a non-presentist ontology. The goal of this essay is to show that the epistemic problem can be rephrased as a pessimistic induction. By doing so, I will show that the epistemic problem, in fact, stems from the A-theoretic ideology alone. Hence, once it is properly (...) presented, the epistemic problem presents a serious threat to all A-theories. (shrink)

It is often suggested that disagreement among scientific experts is a reason not to trust those experts, even about matters on which they are in agreement. In direct opposition to this view, I argue here that the very fact that there is disagreement among experts on a given issue provides a positive reason for non-experts to trust that the experts really are justified in their attitudes towards consensus theories. I show how this line of thought can be spelled out in (...) three distinct frameworks for non-deductive reasoning: namely, Bayesian Confirmation Theory, Inference to the Best Explanation, and Inferential Robustness Analysis. (shrink)

Richard Feldman has proposed and defended different versions of a principle about evidence. In slogan form, the principle holds that ‘evidence of evidence is evidence’. Recently, Branden Fitelson has argued that Feldman’s preferred rendition of the principle falls pray to a counterexample related to the non-transitivity of the evidence-for relation. Feldman replies arguing that Fitelson’s case does not really represent a counterexample to the principle. In this note, we argue that Feldman’s principle is trivially true.

When it comes to disagreements about religious, moral or political questions, many people consider a tolerant ‘live-and-let-live’ attitude to be the best reaction toward conflicting opinions. However, many epistemologists are rather skeptical about the epistemic acceptability of such a tolerant attitude. More specifically, the worry is that a tolerant reaction toward recognized disagreement is necessarily epistemically irrational. After setting out this worry in a little more detail, I will present and discuss three different arguments for the epistemic irrationality of a (...) tolerant attitude toward disagreement. I will argue that while all these arguments ultimately fail, they still reveal some substantial limitations to the epistemic adequacy of intellectual tolerance. (shrink)

This article examines the central epistemological issues tied to the recognition of disagreement.

Hempel’s Converse Consequence Condition (CCC), Entailment Condition (EC), and Special Consequence Condition (SCC) have some prima facie plausibility when taken individually. Hempel, though, shows that they have no plausibility when taken together, for together they entail that E confirms H for any propositions E and H. This is “Hempel’s paradox”. It turns out that Hempel’s argument would fail if one or more of CCC, EC, and SCC were modified in terms of explanation. This opens up the possibility that Hempel’s paradox (...) can be solved by modifying one or more of CCC, EC, and SCC in terms of explanation. I explore this possibility by modifying CCC and SCC in terms of explanation and considering whether CCC and SCC so modified are correct. I also relate that possibility to Inference to the Best Explanation. (shrink)

How should one's beliefs be affected by one's knowing that other people, who are equally well-informed, rational, and intelligent – in other words, persons who are epistemic, or intellectual, peers – believe differently? In this thesis I look at a certain answer to this question. Richard Feldman argues that when two persons who have the same level of intelligence and who are equally well-informed disagree, the only rational response is for both persons to give up their disputed beliefs and suspend (...) judgment. I look at two objections to Feldman’s view, one from Ernest Sosa and the other from Thomas Kelly. In the end, I side with Feldman. Feldman’s call for suspension of judgment is based on an observation of symmetry in peer disagreements. Feldman argues that, in a peer disagreement, the participants should realize that for each thing one of them can say in support of his view, the other can say something analogous in support of the other view. This symmetry removes any rational basis to prefer one’s own view. I conclude that neither Sosa’s nor Kelly’s objections introduce any relevant asymmetries that would justify the disputants in a peer disagreement in sticking to their original beliefs. (shrink)