Princeton University | Department of Philosophy | Philosophy Faculty | Thomas Kelly | Online Papers


"Evidence Can Be Permissive"

My contribution to a debate with Roger White (MIT). I argue against the “Uniqueness Thesis”, according to which a given body of evidence always singles out some uniquely rational doxastic attitude towards a particular proposition, for any agent. Although this short paper is written as a response to White, it should be intelligible when read on its own.

"Disagreement and the Burdens of Judgment"

According to David Christensen, the division between "conciliationists" and "non-conciliationists" in the epistemology of disagreement literature is underwritten by the fact that the former accept, while the latter reject, a principle that he calls Independence. I argue that we have good reason to reject the relevant principle. In addition, I compare cases of peer disagreement with cases of (i) intrapersonal conflict, (ii) disagreements with Great Dead Philosophers, and (iii) disagreements with one's past self. I argue that these comparisons tell against broadly conciliationist views.

"Quine and Epistemology"

For Quine, as for many canonical philosophers since Descartes, epistemology stands at the very center of philosophy. In this chapter, I discuss some central themes in Quine’s epistemology. I attempt to provide some historical context for Quine’s views, in order to make clear why they were seen as such radical challenges to then prevailing orthodoxies within analytic philosophy. I also highlight aspects of his views that I take to be particularly relevant to contemporary epistemology.

"Taking Things for Granted"

In the course of responding to Harman and Sherman's paper "Knowledge and Assumptions", I propose two norms on taking things for granted. First, one should take something for granted only if one knows that it's true. Second, one should take something for granted only if the expected utility of doing so exceeds the expected utility of not doing so.

"Consensus Gentium: Twenty-First Century Reflections on the 'Common Consent' Argument for the Existence of God"

According to proponents of the common consent argument for the existence of God, widespread belief in God provides good reason to believe that God exists. I consider what might be said for and against a modest version of the argument.

"Is Reflective Equilibrium Enough?" (with Sarah McGrath)

Suppose that one is at least a minimal realist about a given domain, in that one thinks that that domain contains truths that are not in any interesting sense of our own making. Given such an understanding, what can be said for and against the method of reflective equilibrium as a procedure for investigating the domain? We explore this question, with special attention to the work of three of the method's most influential proponents: Nelson Goodman, John Rawls and Thomas Scanlon.

"Peer Disagreement and Higher Order Evidence"

A sequel to my earlier paper, 'The Epistemic Significance of Disagreement' (2005). How should we respond to the phenomenon of peer disagreement? I criticize 'The Equal Weight View' (Elga, Feldman, Christensen) and develop and defend an alternative theory.

"Hume, Norton, and Induction without Rules"

Does Hume's skeptical critique of inductive reasoning depend for its force on the assumption that such reasoning is a matter of following general rules? I explore the question in connection with John Norton's "Material Theory of Induction". This short piece was my contribution to the symposium "Induction Without Rules" at the 2008 Biennial Meetings of the Philosophy of Science Association. The other symposiasts were Peter Achinstein (Johns Hopkins), John Norton (Pittsburgh HPS) and John Worrall (LSE).

"Following the Argument Where It Leads"

Throughout the history of western philosophy, the Socratic injunction to 'follow the argument where it leads' has exerted a powerful attraction. But what is it, exactly, to follow the argument where it leads? I explore this intellectual ideal and offer a modest proposal as to how we should understand it. On my proposal, following the argument where it leaves involves a kind of modalized reasonable- ness. I then consider the relationship between the ideal and common sense or 'Moorean' responses to revisionary philosophical theorizing.

"Disagreement, Dogmatism, and Belief Polarization"

Suppose that you and I disagree about some non-straightforward matter of fact (say, about whether capital punishment tends to have a deterrent effect on crime). Psychologists have demonstrated the following striking phenomenon: if you and I are subsequently exposed to a mixed body of evidence that bears on the question, doing so tends to increase the extent of our initial disagreement. That is, in response to exactly the same evidence, each of us grows increasingly confident of his or her original view; we thus become increasingly polarized as our common evidence increases. I consider several alternative models of how people reason about newly-acquired evidence which seems to disconfirm their prior beliefs. I then explore the normative implications of these models for the phenomenon in question.

"Common Sense as Evidence: Against Revisionary Ontology and Skepticism"

How far might philosophy succeed in undermining our ordinary, common sense views about what there is or what we know? I explore this issue, with special attention to the status of 'Moorean' responses to radically revisionary theories in metaphysics and epistemology. I defend such responses against the charge that they are dogmatic.

"Evidence: Fundamental Concepts and the Phenomenal Conception"

The concept of evidence is among the central concerns of epistemology broadly construed. As such, it has long engaged the intellectual energies of both philosophers of science and epistemologists of a more traditional variety. Here I briefly survey some of the more important ideas to have emerged from this tradition of reflection. I then look somewhat more closely at an issue that has recently come to the fore, largely as a result of Williamson (2000): that of whether one's evidence supervenes on one's non-factive mental states.


The concept of evidence is among the central concerns of epistemology broadly construed. As such, it has long engaged the intellectual energies of both philosophers of science and epistemologists of a more traditional variety. Here I briefly survey some of the more important ideas to have emerged from this tradition of reflection, with special emphasis on some recent developments of note.

"Evidence and Normativity: Reply to Leite"

A defense of my previous paper, "Epistemic Rationality as Instrumental Rationality: A Critique" against some recent criticisms by Adam Leite.

"The Cost of Skepticism: Who Pays?"

Those who favor externalist accounts of knowledge and justification often accuse their internalist opponents of playing into the hands of skeptic. According to this line of thought, internalists characteristically set overly demanding requirements for knowledge and justification, requirements which ordinary believers infrequently satisfy: the internalist is thus committed by his or her own theory to a massive and implausible revisionism about the extent of what we know and justifiably believe. For reasons that I explore, the version of internalist foundationalism developed by BonJour might seem particularly vulnerable to this charge. Given this, one of the most striking and provocative claims of the present work is BonJour's insistence that his theory fares no worse than--and indeed, compares favorably with--Sosa's externalist virtue theory with respect to the issue of skepticism. My primary concern in this short paper is to evaluate BonJour's claim.

"The Epistemic Significance of Disagreement"

It is a striking fact that almost everyone holds at least some beliefs that are explicitly rejected by others who have been exposed to all of the same evidence and arguments. When a belief that one holds is explicitly rejected by individuals over whom one possesses no discernible epistemic advantage, does this give one a reason for skepticism about that belief? In deciding what to believe about some controversial question, how (if at all) should one take into account the considered judgements of one's epistemic peers? I explore these and related questions. I argue that an awareness of the relevant kind of disagreement need not undermine the rationality of maintaining one's original views.

"Moorean Facts and Belief Revision, or Can the Skeptic Win?"

A Moorean fact, in the words of the late David Lewis, is 'one of those things that we know better than we know the premises of any philosophical argument to the contrary'. Although appeals to Moorean facts are denigrated by some, such appeals are championed by others. Indeed, the need to respect the Moorean facts is often emphasized in explicit discussions of philosophical methodology. Despite this, the concept of a Moorean fact has received little extended scrutiny. My aim here is to contribute to the rectification of this state of affairs.

"Sunk Costs, Rationality, and Acting for the Sake of the Past"

If you are more likely to continue a course of action in virtue of having previously invested in that course of action, then you tend to honor sunk costs. It is widely thought both that (i) individuals often do give some weight to sunk costs in their decision-making and that (ii) it is irrational for them to do so. In this paper I attempt to cast doubt on the conventional wisdom about sunk costs, understood as the conjunction of these two claims.

"Epistemic Rationality as Instrumental Rationality: A Critique"

n this paper, I explore the relationship between epistemic rationality and instrumental rationality, and I attempt to delineate their respective roles in typical instances of theoretical reasoning. My primary concern is with the instrumentalist conception of epistemic rationality: the view that epistemic rationality is simply a species of instrumental rationality, viz. instrumental rationality in the service of one's cognitive or epistemic goals. After sketching the relevance of the instrumentalist conception to debates over naturalism and 'the ethics of belief', I argue that, despite enjoying considerable popularity among both epistemologists and philosophers of science, it is ultimately indefensible. Having thus argued for the distinctness of epistemic and instrumental rationality, I attempt to clarify the role played by each in typical instances of theoretical reasoning. I suggest that being theoretically rational--that is, being proficient with respect to theoretical reasoning--is best construed as a hybrid virtue, inasmuch as it involves manifesting sensitivity to two very different kinds of reasons.

"The Rationality of Belief and Some Other Propositional Attitudes"

In this paper, I explore the question of whether the expected consequences of holding a belief can affect the rationality of doing so. Special attention is given to various ways in which one might attempt to exert some measure of control over what one believes and the normative status of the beliefs that result from the successful execution of such projects. I argue that the lessons which emerge from thinking about the case of belief have important implications for the way we should think about the rationality of a number of other propositional attitudes, such as regret, desire, and fear. Finally, I suggest that a lack of clarity with respect to the relevant issues has given rise to a number of rather serious philosophical mistakes.
updated: 16 Jun 2014