Luminosity and the KK Thesis

A mental state is luminous if and only if being in a state of that kind always puts one in a position to know that one is in the state. This chapter is a critique of Timothy Williamson’s margin-of-error argument that no nontrivial states are luminous in this sense. While I agree with Williamson’s rejection of a Cartesian internalist conception of the mind, I argue that an externalist conception (one based on information theory) can be reconciled with the luminosity of intentional mental states such as knowledge. My argument, which uses an artificial and simplified model of knowledge, is not a direct rebuttal to his argument, as applied to a more realistic notion of the knowledge of human beings, but I argue that it shows that a luminosity assumption is compatible with externalism about knowledge, and it suggest an intuitively plausible strategy for resisting his argument.

Dispositions and Chance

This chapter develops a suggestion of Nelson Goodman that one should see the problem of explaining dispositional predicates and the problem of constructing an adequate theory of confirmation as aspects of the same underlying problem. It is argued that projectivism—the strategy of connecting rules of inductive practice with the development of theoretical descriptive concepts—does not imply quasi-realism, but is compatible with a thoroughly realistic understanding of those concepts. After a general discussion of the role of dispositional properties, the chapter looks in more detail at one kind of dispositional theory—a propensity account of objective chance—where the conceptual connection between concepts for giving a theoretical description of the world and rules of inductive practice is particularly explicit.

Counterfactuals and Humean Reduction

This chapter comprises an exposition and critique of David Lewis’s metaphysical thesis of Humean supervenience and the reductive account of counterfactuals and other concepts in the natural necessity family that is given in this framework. Hume’s rejection of primitive natural necessity was grounded in his empiricist epistemology, but Lewis’s Humean metaphysics involves a radical separation of metaphysical and epistemological principles, and it is argued in this chapter that his metaphysics is unmotivated, and requires an implausible conception of the nature of fundamental natural properties. The chapter defends an alternative picture that picks up on a different more naturalistic Humean theme, tying the cluster of concepts that involve natural necessity to their role in an explanation of inductive practice.

Reflection, Endorsement, Calibration

A discussion of van Fraassen’s reflection principle: that an agent’s current credence in a proposition should coincide with his expectation of his future credence in that proposition. It is agreed by all that the principle needs to be qualified, but even qualified versions of the principle remain controversial. This chapter proposes a way of restricting, and then generalizing the principle. It is argued that the resulting principle is defensible, and that it can help to clarify some issues in epistemology. The qualifications involve a notion of endorsement that, it is argued, has interest beyond its use in the defense of the reflection principle. The more general issue in the background concerns the role of one’s information about the information possessed by others, and by oneself at other times, in constraining and justifying one’s current credences, and one’s judgments about what one knows.

Modeling a Perspective on the World

It is argued, following David Lewis, that we should model a cognitive state by a set of centered possible worlds, since this is required to represent the believer’s self-locating or indexical knowledge and belief. But it is also argued, contra Lewis, that we should take the contents of belief to be propositions, represented by sets of uncentered possible worlds, since this is required to give a perspicuous account of agreement and disagreement of different agents, and of change of belief over time. Reconciling these two thoughts requires a defense of Propositionality: roughly, the thesis that any ignorance of where one is in the world is also ignorance about what the world in itself is like. This thesis is defended against some criticisms, and motivated by an externalist picture of knowledge and intentionality.

Introduction

More than thirty years ago I wrote a book called Inquiry. This was a great title for a philosophy book, with its allusion (or homage) to classic works in the empiricist tradition, and it was an appropriate title for the aspirations with which the book was written: its topic, I said in the preface, was the abstract structure of inquiry. But it is less clear that this was an appropriate title for what was actually accomplished in the book since it did not get much beyond preliminary setting up of the issues, and some exposition of and motivation for the formal apparatus that I planned to use to talk about the structure of inquiry. Before getting to the main issues, I had to explain and motivate my approach to the problem of intentionality, sketch and motivate the formal apparatus used to represent that approach (possible worlds semantics), and respond to problems that the approach faced. That took up most of the book. The rest of it focused mainly on another piece of apparatus needed to represent the dynamics of belief (a formal semantics for conditionals), and I was able to make only a start on a discussion of the role of this apparatus in forming and refining both rules for revising beliefs, and concepts for giving a theoretical description of the world....

On the Logics of Knowledge and Belief

A model theory for a logic of both knowledge and belief (epistemic logic) is spelled out and defended. The chapter explores some consequences of the assumptions that motivate the theory, some alternative ways that the theory might be extended, and some ways in which this kind of model theory might throw light on traditional problems in epistemology. The main focus is the relation between knowledge and belief, and on some parallels between issues that emerged from the project of responding to the Gettier problem and issues in the more formal framework about the relations between the accessibility relations for belief and knowledge operators.

Conditional Propositions and Conditional Assertions

A comparison of accounts of indicative conditional statements that treat them as a distinctive kind of conditional speech act—qualified assertion of the consequent qualified by the supposition of the antecedent—and accounts that treat them as unqualified assertions of propositions that are a function of antecedent and consequent. The aim is to reconcile the two accounts by making them precise in a common pragmatic framework, and showing that the former can be seen to be equivalent to a limiting case of the latter. It is argued that this way of representing the conditional assertion account helps to explain the relation between indicative and subjunctive conditionals.

Counterfactuals and Probability

This chapter continues the attempt, begun in chapter 10, to reconcile the thesis that conditionals have truth conditions with accounts such as Dorothy Edgington’s that aim to explain conditionals as expressing a distinctive kind of attitude represented by conditional probability. This time the focus is on subjunctive or counterfactual conditionals. It is argued that the propositional analysis helps to explain the cases, emphasized by Edgington, where counterfactual statements seem to be retrospective assessment of what was earlier said with an indicative conditional. It is also argued that the propositional analysis can allow for cases where counterfactuals have probability values but not truth-values, and more generally that it can help to explain the relationship between counterfactuals and objective chance.

Contextualism and the Logic of Knowledge

A discussion of contextualist accounts of knowledge, and of the epistemic logic that is appropriate to them. David Lewis’s account is compared and contrasted with an alternative, a version of an information-theoretic, “normal conditions” analysis of knowledge. The two accounts are formulated in a common abstract framework making it possible to clarify the structural features they share, and those on which they differ. Central concerns of the discussion are the interplay between facts about the attributor’s context and facts about the subject of the knowledge attribution, and the dynamics of knowledge attribution as contexts shift in response to changes in the epistemic situation of both the attributors and the subject.