Is Every Theory of Knowledge False?

Is knowledge consistent with literally any credence in the relevant proposition, including credence 0? Of course not. But is credence 0 the only credence in p that entails that you don't know that p? Knowledge entails belief (most epistemologists think), and it's impossible to believe that p while having credence 0 in p. Is it true that, for every value of ‘x,’ if it's impossible to know that p while having credence x in p, this is simply because it's impossible to believe that p while having credence x in p? If so, is it possible to believe that p while having (say) credence 0.4 in p? These questions aren't standard epistemological fare—at least in part because many epistemologists think their answers are obvious—but they have unanticipated consequences for epistemology. Let ‘improbabilism’ name the thesis that it's possible to know that p while having a credence in p below 0.5. Improbabilism will strike many epistemologists as absurd, but careful reflection on these questions reveals that, if improbabilism is false, then all of the most plausible theories of knowledge are also false. Or so I shall argue in this paper. Since improbabilism is widely rejected by epistemologists (at least implicitly), this paper reveals a tension between all of the most plausible theories of knowledge and a widespread assumption in epistemology.     

Permissive Situations and Direct Doxastic Control

According to what I will call ‘the disanalogy thesis,’ beliefs differ from actions in at least the following important way: while cognitively healthy people often exhibit direct control over their actions, there is no possible scenario where a cognitively healthy person exhibits direct control over her beliefs. Recent arguments against the disanalogy thesis maintain that, if you find yourself in what I will call a ‘permissive situation’ with respect to p, then you can have direct control over whether you believe p, and you can do so without manifesting any cognitive defect. These arguments focus primarily on the idea that we can have direct doxastic control in permissive situations, but they provide insufficient reason for thinking that permissive situations are actually possible, since they pay inadequate attention to the following worries: permissive situations seem inconsistent with the uniqueness thesis, permissive situations seem inconsistent with natural thoughts about epistemic akrasia, and vagueness threatens even if we push these worries aside. In this paper I argue that, on the understanding of permissive situations that is most useful for evaluating the disanalogy thesis, permissive situations clearly are possible.     

An evaluation of simultaneous and sequential presentation of preferred and nonpreferred food to treat food selectivity

In the current investigation, we compared two methods of food presentation (simultaneous vs. sequential) to increase consumption of nonpreferred food for 3 children with food selectivity. In the simultaneous condition, preferred foods were presented at the same time as nonpreferred food (e.g., a piece of broccoli was presented on a chip). In the sequential condition, acceptance of the nonpreferred food resulted in presentation of the preferred food. Increases in consumption occurred immediately during the simultaneous condition for 2 of the 3 participants. For 1 participant, increases in consumption occurred in the simultaneous condition relative to the sequential condition, but only after physical guidance and re-presentation were added to treatment. Finally, consumption increased for 1 participant in the sequential condition, but only after several sessions. These results are discussed in terms of possible mechanisms that may alter preferences for food (i.e., establishing operations, flavor-flavor conditioning).     

Shepherd Ivory Franz: His contributions to neuropsychology and rehabilitation

Shepherd I. Franz was an important figure in psychology of the last century, and historians of psychology have given recognition to much of his work. However, his experimental work with animals and his pioneer investigations in experimental and clinical neuropsychology have been largely ignored. This article reviews his conceptual, assessment, and treatment contributions, including (1) his pioneering work on the use of learned behavior as a baseline for the study of cerebral ablations, (2) his interest in brain plasticity, (3) his development of comprehensive psychological assessment methods, and (4) his work on the rehabilitation of neurological patients with techniques derived from his animal experiments. His work predated much of what is now part of the conceptual substance of the experimental and clinical neurosciences.     

Odorant quality perception: a metric individual differences approach

Perceptual spaces, in which similar stimuli are located close to each other and dissimilar stimuli are located far apart, have aided in the understanding of the physiological and psychological bases for sensory quality coding. Differences in perception between individuals should be reflected by differences in the spatial relationships between stimuli. If the dimensionality of the perceptual space is small (e.g., color space), individual differences that reflect specific pathologies are readily apparent from visual inspection. On the other hand, if the dimensionality of the perceptual space is large (as is proposed for odor space), visual inspection alone may not reveal individual differences in quality perception. The present work presents an information-theory-based method for quantifying individual differences in quality perception from perceptual confusion matrices. The ability of this method to quantify individual differences in quality perception is shown in a hypothetical example of specific anosmia. Finally, the method is applied to the examination of intrasubject consistency of odorant quality perception.     

Stress, self-esteem, and suicidal ideation in late adolescents

The relationships among stress, self-esteem, and suicidal ideation in late adolescents were examined in a group of college students. Multiple regression analysis indicated that both stress and self-esteem were significantly related to suicidal ideation; low self-esteem and stressful life events significantly predicted suicidal ideation. The hypothesis that self-esteem would moderate the effects of life stressors on suicidal ideation was supported at the .06 level. A significant minority of the sample indicated having thoughts severe enough to be classified as clinical suicidal ideation. In general, participants who had experienced negative life events in the 6 to 12 months prior to participating in the study had lower self-esteem than those who had similar stresses within the prior six months. However, the opposite was true for clinical suicidal ideators; those who experienced negative life stressors recently had lower self-esteem than those who experienced negative life events six months to a year in the past.     

How do speakers avoid ambiguous linguistic expressions?

Three experiments assessed how speakers avoid linguistically and nonlinguistically ambiguous expressions. Speakers described target objects (a flying mammal, bat) in contexts including foil objects that caused linguistic (a baseball bat) and nonlinguistic (a larger flying mammal) ambiguity. Speakers sometimes avoided linguistic-ambiguity, and they did so equally regardless of whether they also were about to describe foils. This suggests that comprehension processes can sometimes detect linguistic-ambiguity before producing it. However, once produced, speakers consistently avoided using the same linguistically ambiguous expression again for a different meaning. This suggests that production processes can successfully detect linguistic-ambiguity after-the-fact. Speakers almost always avoided nonlinguistic-ambiguity. Thus, production processes are especially sensitive to nonlinguistic- but not linguistic-ambiguity, with the latter avoided consistently only once it is already articulated.     

Effects of modeling and topic stimulus on self-referent touching

Self-touching is defined as self-directed touches, e.g., scratching or rubbing, that have no apparent conscious motivation. Earlier research on self-touching focused on internal processes associated with self-touching, e.g., mental conflict, while more recent research has considered external motivators, such as an auditory or visual presentation of a provocative stimulus, e.g., leeches. Here, 110 undergraduate psychology students (68 women, 42 men; M age = 18.7 yr., SD = 1.0) were shown a video about chiggers to replicate previous findings, while simultaneously studying the social influence of self-touching modeled by the presenter. A significant interaction was found as modeled self-touching significantly increased participants' self-touching when they were also attending to the video about chiggers. The results are discussed in terms of potential processes underlying this behavior and directions for research.     

Perspective and prejudice: antecedents and mediating mechanisms

The present work investigated mechanisms by which Whites' prejudice toward Blacks can be reduced (Study 1) and explored how creating a common ingroup identity can reduce prejudice by promoting these processes (Study 2). In Study 1, White participants who viewed a videotape depicting examples of racial discrimination and who imagined the victim's feelings showed greater decreases in prejudice toward Blacks than did those in the objective and no instruction conditions. Among the potential mediating affective and cognitive variables examined, reductions in prejudice were mediated primarily by feelings associated with perceived injustice. In Study 2, an intervention designed to increase perceptions of a common group identity before viewing the videotape, reading that a terrorist threat was directed at all Americans versus directed just at White Americans, also reduced prejudice toward Blacks through increases in feelings of injustice.