Belief revision,epistemic conditionals and the Ramsey test

Epistemic conditionals have often been thought to satisfy the Ramsey test (RT): If A, then B is acceptable in a belief state G if and only if B should be accepted upon revising G with A. But as Peter Gärdenfors has shown, RT conflicts with the intuitively plausible condition of Preservation on belief revision. We investigate what happens if (a) RT is retained while Preservation is weakened, or (b) vice versa. We also generalize Gärdenfors' approach by treating belief revision as a relation rather than as a function.In our semantic approach, the same relation is used to model belief revision and to give truth-conditions for conditionals. The approach validates a weak version of the Ramsey Test (WRR) — essentially, a restriction of RT to maximally consistent belief states.We prove that alternatives (a) and (b) are both consistent, but argue that (b) is philosophically more promising. Gärdenfors' belief-revision axioms are compatible with WRR together with RT from left to right: the only direction of the test that is defensible on intuitive grounds.An earlier version of this paper was presented at the conference on the dynamics of knowledge and belief at Lund University, 24–26 August 1989. We wish to thank Sven Danielsson, Peter Gärdenfors, Sören Halldén, David Makinson, Hugh Mellor, Michael Morreau, Nils-Eric Sahlin and Brian Skyrms for their very helpful suggestions and remarks. We are also grateful for thought-provoking criticism and comments from two anonymous referees.     

Chisholm's Internalism and Its Consequences

Abstract: Among the important themes in Roderick Chisholm's epistemology are his commitment to internalism, his defense of the independence of epistemology from empirical science, and his assumption that we do know most of what we initially think we know. In “Roderick Chisholm and the Shaping of American Epistemology” Hilary Kornblith argues that Chisholm's views lead to a radical divorce between the factors that justify beliefs and the factors that cause beliefs, that Chisholm's views have the consequence that there is no connection between justification and truth, and that Chisholm's kind of epistemology is unable to give epistemic advice. I argue that Chisholm's views do not have these consequences.     

Propositional epistemic luck,epistemic risk,and epistemic justification

If a subject has a true belief, and she has good evidence for it, and there’s no evidence against it, why should it matter if she doesn’t believe on the basis of the good available evidence? After all, properly based beliefs are no likelier to be true than their corresponding improperly based beliefs, as long as the subject possesses the same good evidence in both cases. And yet it clearly does matter. The aim of this paper is to explain why, and in the process delineate a species of epistemic luck that has hitherto gone unnoticed—what we call propositional epistemic luck—but which we claim is crucial to accounting for the importance of proper basing. As we will see, in order to understand why this type of epistemic luck is malignant, we also need to reflect on the relationship between epistemic luck and epistemic risk.     

Scepticism,epistemic luck,and epistemic angst

A commonly expressed worry in the contemporary literature on the problem of epistemological scepticism is that there is something deeply intellectually unsatisfying about the dominant anti-sceptical theories. In this paper I outline the main approaches to scepticism and argue that they each fail to capture what is essential to the sceptical challenge because they fail to fully understand the role that the problem of epistemic luck plays in that challenge. I further argue that scepticism is best thought of not as a quandary directed at our possession of knowledge simpliciter, but rather as concerned with a specific kind of knowledge that is epistemically desirable. On this view, the source of scepticism lies in a peculiarly epistemic form of angst.

It is always by favour of Nature that one knows something.     

A puzzle for epistemic WAMs

Synthese - In recent literature, a very popular position about the normativity of assertion claims that standards for epistemically proper assertion vary with practical context, while standards for...     

Weighing epistemic and practical reasons for belief

Philosophical Studies - This paper is about how epistemic and practical reasons for belief can be compared against one another when they conflict. It provides a model for determining what one ought...     

Safety and epistemic luck

There is some consensus that for S to know that p, it cannot be merely a matter of luck that S’s belief that p is true. This consideration has led Duncan Pritchard and others to propose a safety condition on knowledge. In this paper, we argue that the safety condition is not a proper formulation of the intuition that knowledge excludes luck. We suggest an alternative proposal in the same spirit as safety, and find it lacking as well.     

Mandarin speech perception by ear and eye follows a universal principle

In this study, the nature of speech perception of native Mandarin Chinese was compared with that of American English speakers, using synthetic visual and auditory continua (from /ba/ to /da/) in an expanded factorial design. In Experiment 1, speakers identified synthetic unimodal and bimodal speech syllables as either /ba/ or /da/. In Experiment 2, Mandarin speakers were given nine possible response alternatives. Syllable identification was influenced by both visual and auditory sources of information for both Mandarin and English speakers. Performance was better described by the fuzzy logical model of perception than by an auditory dominance model or a weighted-averaging model. Overall, the results are consistent with the idea that although there may be differences in information (which reflect differences in phonemic repertoires, phonetic realizations of the syllables, and the phonotactic constraints of languages), the underlying nature of audiovisual speech processing is similar across languages.     

A logic for epistemic two-dimensional semantics

Epistemic two-dimensional semantics is a theory in the philosophy of language that provides an account of meaning which is sensitive to the distinction between necessity and apriority. While this theory is usually presented in an informal manner, I take some steps in formalizing it in this paper. To do so, I define a semantics for a propositional modal logic with operators for the modalities of necessity, actuality, and apriority that captures the relevant ideas of epistemic two-dimensional semantics. I also describe some properties of the logic that are interesting from a philosophical perspective, and apply it to the so-called nesting problem.     

Memory and epistemic conservatism

Much of the plausibility of epistemic conservatism derives from its prospects of explaining our rationality in holding memory beliefs. In the first two parts of this paper, I argue for the inadequacy of the two standard approaches to the epistemology of memory beliefs, preservationism and evidentialism. In the third, I point out the advantages of the conservative approach and consider how well conservatism survives three of the strongest objections against it. Conservatism does survive, I claim, but only if qualified in certain ways. Appropriately qualified, conservatism is no longer the powerful anti-skeptical tool some have hoped for, but a doctrine closely connected with memory.     

Knowledge and epistemic necessity

Claims of the form ??I know P and it might be that not-P?? tend to sound odd. One natural explanation of this oddity is that the conjuncts are semantically incompatible: in its core epistemic use, ??Might P?? is true in a speaker??s mouth only if the speaker does not know that not-P. In this paper I defend this view against an alternative proposal that has been advocated by Trent Dougherty and Patrick Rysiew and elaborated upon in Jeremy Fantl and Matthew McGrath??s recent Knowledge in an Uncertain World.