Knowing and Checking: An Epistemological Investigation, Routledge

A major and very common objection against Nozick’s theory of knowledge is that it is incompatible with a very plausible and important epistemic principle, namely the principle that knowledge is closed under known entailment (the “principle of closure”). Nozick himself openly stated that his account of knowledge is incompatible with closure – and stuck with the theory. Most philosophers went the other way and stuck with closure, giving up on any theory like Nozick’s which seems incompatible with closure. If anything is a candidate for a “killer objection” to Nozick’s account, then it is based on his view on closure. - In this paper I argue first that at least in many cases Nozick is not forced to deny common closure principles. Second, and much more importantly, Nozick does not – despite first (and second) appearances and despite his own words – deny closure. On the contrary, he is defending a more sophisticated and complex principle of closure. This principle does remarkably well though it is not without problems. It is surprising how rarely Nozick’s principle of closure has been discussed. He should be seen not so much as a denier of closure than as someone who’s proposing an alternative, more complex principle of closure.

Erkenntnis 79(1), 45-54, 2014

Keith DeRose’s solution to the skeptical problem is based on his indirect sensitivity account. Sensitivity is not a necessary condition for any kind of knowledge, as direct sensitivity accounts claim, but the insensitivity of our beliefs that the skeptical hypotheses are false explains why we tend to judge that we do not know them. The orthodox objection line against any kind of sensitivity account of knowledge is to present instances of insensitive beliefs that we still judge to constitute knowledge. This objection line offers counter-examples against the claim of direct sensitivity accounts that sensitivity is necessary for any kind of knowledge. These examples raise an easy problem for indirect sensitivity accounts that claim that there is only a tendency to judge that insensitive beliefs do not constitute knowledge, which still applies to our beliefs that the skeptical hypotheses are false. However, a careful analysis reveals that some of our beliefs that the skeptical hypotheses are false are sensitive; nevertheless, we still judge that we do not know them. Therefore, the fact that some of our beliefs that the skeptical hypotheses are false are insensitive cannot explain why we tend to judge that we do not know them. Hence, indirect sensitivity accounts cannot fulfill their purpose of explaining our intuitions about skepticism. This is the hard problem for indirect sensitivity accounts.

Philosophia 45(4), 1741-1747, 2017

In this paper, I defend the heterogeneity problem for sensitivity accounts of knowledge against an objection that has been recently proposed by Wallbridge in Philosophia (2016b). I argue in (Melchior 2015) that sensitivity accounts of knowledge face a heterogeneity problem when it comes to higher-level knowledge about the truth of one's own beliefs. Beliefs in weaker higher-level propositions are insensitive, but beliefs in stronger higher-level propositions are sensitive. The resulting picture that we can know the stronger propositions without being in a position to know the weaker propositions is too heterogeneous to be plausible. Wallbridge objects that there is no heterogeneity problem because beliefs in the weaker higher-level propositions are also sensitive. I argue against Wallbridge that the heterogeneity problem is not solved but only displaced. Only some beliefs in the weaker higher-level propositions are sensitive. I conclude that the heterogeneity problem is one of a family of instability problems that sensitivity accounts of knowledge face and that Wallbridge's account raises a further problem of this kind.

Journal of Philosophical Research, 2017

I present an argument for a sophisticated version of skeptical invariantism that has so far gone unnoticed: Bifurcated Skeptical Invariantism (BSI). I argue that it can, on the one hand, (dis)solve the Gettier problem, address the dogmatism paradox and, on the other hand, show some due respect to the Moorean methodological incentive of 'saving epistemic appearances'. A fortiori, BSI promises to reap some other important explanatory fruit that I go on to adduce (e.g. account for concessive knowledge attributions). BSI can achieve this much because it distinguishes between two distinct but closely interrelated (sub)concepts of (propositional) knowledge, fallible-but-safe knowledge and infallible-and-sensitive knowledge, and explains how the pragmatics and the semantics of knowledge discourse operate at the interface of these two (sub)concepts of knowledge. I conclude that BSI is a novel theory of knowledge discourse that merits serious investigation.

(2017) Philosophia. In a recent paper, Melchior pursues a novel argumentative strategy against the sensitivity condition. His claim is that sensitivity suffers from a 'heterogeneity problem:' although some higher-order beliefs are knowable, other, very similar, higher-order beliefs are insensitive and so not knowable. Similarly, the conclusions of some bootstrapping arguments are insensitive, but others are not (and since one motivation for endorsing the sensitivity condition was to provide an explanation of what goes wrong in bootstrapping arguments, this motivation is undermined). In reply, I show that sensitivity does not treat different higher-order beliefs differently in the way that Melchior states and that while genuine bootstrapping arguments have insensitive conclusions, the cases that Melchior describes as sensitive 'bootstrapping' arguments don't deserve the name, since they are a perfectly good way of getting to know their conclusions. In sum, sensitivity doesn't have a heterogeneity problem.

Head of the Departmental Graduate Program iii I owe an unpayable debt to my mother Bev Coss, who always stood by me during the rough patches of the dissertation process, never doubting my ability to finish it. Without her, it's doubtful the dissertation would have ever been completed. For this reason, and many others, I dedicate my dissertation to her. iv

It is widely thought that if knowledge requires sensitivity, knowledge is not closed because sensitivity is not closed. This paper argues that there is no valid argument from sensitivity failure to non-closure of knowledge. Sensitivity does not imply non-closure of knowledge. Closure considerations cannot be used to adjudicate between safety and sensitivity accounts of knowledge.