SHUTTING DRETSKE’S DOOR

Dretske proposes a theory of knowledge in terms of a theory of information, but wishes to deny that empirical knowledge settles the large question of scepticism. This leads him to deny the closure of knowledge under known entailment. In a recent paper J?ger argues that Dretske’s theory of information entails closure for knowledge, ‘at least for the kind of propositions here at issue’ (J?ger 2004:194). If J?ger is right, Dretske is seriously embarrassed and must give something up. In this paper I show that there are two flaws in J?ger’s argument. The principle of informational closure considered by J?ger is incompatible with Dretske’s theory of information, and J?ger’s argument that Dretske is committed to a certain kind of substitution instance of that principle of informational closure is invalid. I propose adequacy conditions on signalled information and use them to motivate a formulation of a general closure principle for signalled information. I show that Dretske’s account of information satisfies the adequacy conditions, but in a way which commits him to an instance of the general closure principle. I argue that Dretske is consequently committed to closure for some cases of knowledge for which he wishes to deny closure. Finally, I sketch how, on the basis of the closure principle to which Dretske is committed, J?ger’s broader argument may yet go through.     

In defense of reliabilism

Objections to reliabilist theories of knowledge and justification have looked insuperable. Reliability is a property of the process of belief formation. But the generality problem apparently makes the specification of any such process ambiguous. The externalism of reliability theories clashes with strongly internalist intuitions. The reliability property does not appear closed under truth-preserving inference, whereas closure principles have strong intuitive appeal. And epistemic paradoxes, like the preface and the lottery, seem unavoidable if knowledge or justification depends on the frequency with which a process generates true beliefs. The present theory has the conceptual resources to meet these challenges. It requires that a justificatory belief-formation process be intentionally applied. It distinguishes the justification of beliefs from that of the believer. And it avoids a frequency interpretation of reliability by introducing a notion of the normalcy of conditions under which processes are intentionally used.     

Sceptical possibilities? No worries

This paper undermines a paradigmatic form of sceptical reasoning. It does this by describing, and then dialectically dissolving, the sceptical-independence presumption, upon which that form of sceptical reasoning relies.     

Toward performance specifications for flashing warning beacons

Yellow flashing warning beacons help protect front line service workers, including those in transportation, utility and construction sectors. To safeguard these workers, beacons should be readily detected and should provide veridical information about their relative movement. Two psychophysical laboratory experiments were conducted to provide empirical foundations for two aspects of warning beacon performance, detection and judgments of relative movement. In the first experiment reaction times were measured to the onset of flashing warning beacons varying in peak intensity while observers viewed different scene conditions. Observers also judged the visibility of nearby low-contrast targets in the presence of the flashing warning beacons. Asymptotic response times to the onset of beacons occurred when their peak intensity was at least 750 cd during daytime. Visibility of low contrast targets during nighttime, when glare is most critical, did not decrease substantially when the peak intensity was below 2000 cd. In the second experiment response times were measured to warning beacons of different flash-sequence patterns as they approached the observer. Judgments of gap closure were improved, relative to fully-on/fully-off flashing, with flash sequences where the minimum beacon intensity was at least 10% of the peak intensity and with two synchronized flashing beacons rather than one. With regard to performance specifications, the minimum value for the peak intensity of warning beacons should be 750 cd, with a maximum value of 2000 cd for detection. Fully-on/fully-off flash sequences should be changed to fully-on/partial-off to enhance judgments of gap closure on moving vehicles. Moreover, two flashing warning beacons, rather than one, should be mounted on service vehicles to improve gap closure judgments.     

When experienced regret refuses to fade: Regrets of action and attempting to forget open life regrets

The emotional experience of regret often persists rather then fading over time. The present experiment with 101 student participants investigated whether recollecting life regrets of action, construing life regrets as psychologically open, or attempting to forget versus remember regret-related thoughts interfered with the fading of affect over a two-week interval. Results showed that regrets of action failed to show a fading affect pattern. In addition, disappointment failed to fade for regrets of inaction construed as open. Experienced regret failed to fade for regrets construed as open followed by attempts to forget regret-related thoughts. Intrusive and avoidant thoughts co-occurred with the latter disruptions in fading affect. Discussion concerns the causal relationship of memory and fading affect, and the different processes underlying fading of affect for discrete emotions.     

Mr. Magoo’s mistake

Timothy Williamson has famously argued that the (KK) principle (roughly, that if one knows that p, then one knows that one knows that p) should be rejected. We analyze Williamson’s argument and show that its key premise is ambiguous, and that when it is properly stated this premise no longer supports the argument against (KK). After canvassing possible objections to our argument, we reflect upon some conclusions that suggest significant epistemological ramifications pertaining to the acquisition of knowledge from prior knowledge by deduction.

The Consistency Argument for Ranking Functions

The paper provides an argument for the thesis that an agent’s degrees of disbelief should obey the ranking calculus. This Consistency Argument is based on the Consistency Theorem. The latter says that an agent’s belief set is and will always be consistent and deductively closed iff her degrees of entrenchment satisfy the ranking axioms and are updated according to the ranktheoretic update rules. Special Issue Formal Epistemology I. Edited by Branden Fitelson     

Narrative closure

In this article, “Narrative Closure,” a theory of the nature of narrative closure is developed. Narrative closure is identified as the phenomenological feeling of finality that is generated when all the questions saliently posed by the narrative are answered. The article also includes a discussion of the intelligibility of attributing questions to narratives as well as a discussion of the mechanisms that achieve this. The article concludes by addressing certain recent criticisms of the view of narrative expounded by this article.     

Closure of autobiographical memories moderates their directive effect on behaviour

Specific autobiographical memories have been theorised to serve a directive function, whereby the content of the memory directs behaviour outside awareness. The present research tested whether the extent to which a memory feels low in closure, or psychologically not in the past, moderates this directive effect. A total of 163 participants in an online experiment were asked to recollect a specific autobiographical memory of a time they had failed to donate to charity, or were not asked to recollect a memory. Those who recollected a memory were randomly assigned to think of the memory as high versus low in closure. Recollecting an autobiographical memory made to feel low in closure led to more memory-relevant behaviour than either recollecting a memory made to feel high in closure, or no memory at all. Moreover, the directive effect of a low-closure memory occurred whether participants were made aware of an upcoming behavioural opportunity or not. Discussion centres on possible processes linking low closure and behaviour, as well as implications for the self-memory system theory of autobiographical memory.