When is consensus knowledge based? Distinguishing shared knowledge from mere agreement

Scientific consensus is widely deferred to in public debates as a social indicator of the existence of knowledge. However, it is far from clear that such deference to consensus is always justified. The existence of agreement in a community of researchers is a contingent fact, and researchers may reach a consensus for all kinds of reasons, such as fighting a common foe or sharing a common bias. Scientific consensus, by itself, does not necessarily indicate the existence of shared knowledge among the members of the consensus community. I address the question of under what conditions it is likely that a consensus is in fact knowledge based. I argue that a consensus is likely to be knowledge based when knowledge is the best explanation of the consensus, and I identify three conditions—social calibration, apparent consilience of evidence, and social diversity, for knowledge being the best explanation of a consensus.     

Should knowledge entail belief?

The appropriateness of S5 as a logic of knowledge has been attacked at some length in the philosophical literature. Here one particular attack based on the interplay between knowledge and belief is considered: Suppose that knowledge satisfies S5, belief satisfies KD45, and both the entailment property (knowledge implies belief) and positive certainty (if the agent believes something, she believes she knows it) hold. Then it can be shown that belief reduces to knowledge: it is impossible to have false beliefs. While the entialment property has typically been viewed as perhaps the least controversial of these assumptions, an argument is presented that it can plausibly be viewed as the culprit. More precisely, it is shown that this attack fails if we weaken the entailment property so that it applies only to objective (nonmodal) formulas, rather than to arbitrary formulas. Since the standard arguments in favor of the entailment property are typically given only for objective formulas, this observation suggests that care must be taken in applying intuitions that seem reasonable in the case of objective formulas to arbitrary formulas.Research sponsored in part by the Air Force office of Scientific Research (AFSC), under Contract F49620-91-C-0080. The United States Government is authorized to reproduce and distribute reprints for governmental purposes.     

What is in a tool concept? Dissociating manipulation knowledge from function knowledge

Research on patients with apraxia, a deficit in skilled action, has shown that the ability to use objects may be differentially impaired relative to knowledge about object function. Here we show, using a modified neuropsychological test, that similar dissociations can be observed in response times in healthy adults. Participants were asked to decide which two of three presented objects shared the same manipulation or the same function; triads were presented in picture and word format, and responses were made manually (button press) or with a basic-level naming response (verbally). For manual responses (Experiment 1), participants were slower to make manipulation judgments for word stimuli than for picture stimuli, while there was no difference between word and picture stimuli for function judgments. For verbal-naming responses (Experiment 2), participants were again slower for manipulation judgments over word stimuli, as compared with picture stimuli; however, and in contrast to Experiment 1, function judgments over word stimuli were faster than function judgments over picture stimuli. These data support the hypotheses that knowledge of object function and knowledge of object manipulation correspond to dissociable types of object knowledge and that simulation over motor information is not necessary in order to retrieve knowledge of object function.     

Sosa’s theory of knowledge

Synthese - This paper is a critical discussion of Ernest Sosa’s recent analysis of reflective knowledge.     

Is knowledge a natural kind?

The project of treating knowledge as an empirical object of study has gained popularity in recent naturalistic epistemology. It is argued here that the assumption that such an object of study exists is in tension with other central elements of naturalistic philosophy. Two hypotheses are considered. In the first, “knowledge” is hypothesized to refer to mental states causally responsible for the behaviour of cognitive agents. Here, the relational character of truth creates a problem. In the second hypothesis “knowledge” is hypothesized to refer to mental states causally responsible for the evolutionarily successful behaviour of cognitive agents. Here, the problem lies in the fact that evolution by natural selection is not necessarily conducive to truth. The result does not necessarily amount to eliminativism, however, since the naturalist may consistently reject the condition of truth that lies behind these problems.     

Is knowledge justified true belief?

Is knowledge justified true belief? Most philosophers believe that the answer is clearly ‘no’, as demonstrated by Gettier cases. But Gettier cases don’t obviously refute the traditional view that knowledge is justified true belief (JTB). There are ways of resisting Gettier cases, at least one of which is partly successful. Nevertheless, when properly understood, Gettier cases point to a flaw in JTB, though it takes some work to appreciate just what it is. The nature of the flaw helps us better understand the nature of knowledge and epistemic justification. I propose a crucial improvement to the traditional view, relying on an intuitive and independently plausible metaphysical distinction pertaining to the manifestation of intellectual powers, which supplements the traditional components of justification, truth and belief.     

The indexicality of ‘knowledge’

Epistemic contextualism—the view that the content of the predicate ‘know’ can change with the context of utterance—has fallen into considerable disrepute recently. Many theorists have raised doubts as to whether ‘know’ is context-sensitive, typically basing their arguments on data suggesting that ‘know’ behaves semantically and syntactically in a way quite different from recognised indexicals such as ‘I’ and ‘here’ or ‘flat’ and ‘empty’. This paper takes a closer look at three pertinent objections of this kind, viz. at what I call the Error-Theory Objection, the Gradability Objection and the Clarification-Technique Objection. The paper concludes that none of these objections can provide decisive evidence against contextualism.     

Does knowledge secure warrant to assert?

This paper fortifies and defends the so called Sufficiency Argument (SA) against Classical Invariantism. In Sect. 2, I explain the version of the SA formulated but then rejected by Brown (2008a). In Sect. 3, I show how cases described by Hawthorne (2004), Brown (2008b), and Lackey (forthcoming) threaten to undermine one or the other of the SA’s least secure premises. In Sect. 4, I buttress one of those premises and defend the reinforced SA from the objection developed in Sect. 3.     

Can semantic knowledge influence motion correspondence?

Semantic factors are presumed to have little influence on motion perception. Two experiments examined the effects of an object's semantic identity on motion correspondence using the Ternus paradigm. Motion correspondence was not influenced by whether the object depicted is typically moving or stationary, but it was influenced by the way(s) in which an object's components typically move relative to one another: perceived correspondence differed depending on whether the motion tokens constituted the feet of a person walking or the wheels of a car. Apparently, semantic knowledge can influence motion correspondence, although such influence is weak and may be restricted to certain types of semantic information. The adaptive significance of such restricted influences is considered.     

Automatically deriving readers’ knowledge structures from texts

Latent semantic analysis (LSA) serves as both a theory and a method for representing the meaning of words based on a statistical analysis of their contextual usage (Foltz, 1996; Landauer & Dumais, 1997). In experiments in the domains of psychology and history, we compared the representation of readers’ knowledge structures of information learned from texts with the representation generated by LSA. Results indicated that LSA’s representation is similar to readers’ representations. In addition, the degree to which the reader’s representation is similar to LSA’s representation is indicative of the amount of knowledge the reader has acquired and of the reader’s reading ability. This approach has implications both as a model of learning from text and as a practical tool for performing knowledge assessment.     

Is knowledge of causes sufficient for understanding?

According to a traditional account, understanding why X occurred is equivalent to knowing that X was caused by Y. This paper defends the account against a major objection, viz., knowing-that is not sufficient for understanding-why, for understanding-why requires a kind of grasp while knowledge-that does not. I discuss two accounts of grasp in recent literature and argue that if either is true, then knowing that X was caused by Y entails at least a rudimentary understanding of why X occurred. If my defense is successful, it would cast doubt on an influential account of the epistemic value of understanding.     

Overoptimism about future knowledge: Early arrogance?

Abstract

Three studies explored whether young children (5–7 years) have more optimistic views of their future knowledge than older children (8–12 years) and adults. In Study 1, younger children were more likely than older children and adults to expect greater knowledge in both young and mature protagonists. Both groups of children saw knowledge rising at a faster rate into adulthood than adult participants did. All ages judged moral knowledge as much easier to acquire than other types of knowledge, such as artifacts. In Study 2, all children saw their own future knowledge in especially optimistic terms in comparison to ratings by adults, and the older children exhibited a self-enhancement bias. Study 3 found an overall preference for the acquisition of positively valenced future knowledge, particularly for the 8- to 12-year olds and in the domain of morality, suggesting pragmatic underpinnings for these judgments.     

Stereotypes: static abstractions or dynamic knowledge structures?

Stereotypes have been assumed to be long-lasting knowledge structures that persist even in the face of contrary evidence. However, there is almost no within-participant research relevant to this assumption. The authors describe 4 studies (N=267), the first 3 of which assessed within-participant stereotype stability over a few weeks with measures of stereotypic trait verification, typicality ratings of exemplar sets, and exemplar retrieval. In the 4th study, the authors manipulated context stability. Overall, results showed only low-to-moderate stereotype stability. The stability obtained was a function of the perceived centrality of traits or exemplars and of context constancy. The authors discuss the implications of these results for abstractionist, exemplar, mixed, and connectionist models and identify possible mechanisms that underlie within-participant stereotype instability.     

Is case-based reasoning a source of knowledge generalisation?

This study examines the link between case-based reasoning and knowledge generalisation. Experiment 1 showed that case-based reasoning is not in itself a source of generalisation. In this experiment, subjects were able to adapt knowledge acquired during analysis of an example in order to successfully solve a very similar problem. But immediately afterwards, they failed on a problem symmetrical to the one they had just solved. Experiments 2A and 2B showed, in this same situation, that it is possible to lead subjects to generalise simply by stating that the practice problems were similar to the examples. These findings suggest that knowledge generalisation accompanying case-based reasoning is the result of a process that must be actively implemented by the subject, and not an automatic outcome of the source-to-target transfer.     

When is schematic knowledge used in source monitoring?

Source monitoring involves judgments regarding the origin of information (M. K. Johnson, S. Hashtroudi, & D. S. Lindsay, 1993). When participants cannot remember the source in a source-monitoring task, they may guess according to their prior schematic knowledge (U. J. Bayen, G. V. Nakamura, S. E. Dupuis, & C.-L. Yang, 2000). The present study aimed at specifying conditions under which schematic knowledge is used in source monitoring. The authors examined the time course of schema-based guesses with a response-signal technique (A. V. Reed, 1973), and multinomial models that separate memory and guessing bias. Use of schematic knowledge was observed only when asymptotic old-new recognition was low. The time course of schematic-knowledge retrieval followed an exponential growth function. Implications for theories of source monitoring are discussed.     

Suppressing irrelevant information: knowledge activation or inhibition?

In 3 experiments, the authors examined the role of knowledge activation in the suppression of contextually irrelevant meanings for ambiguous homographs. In Experiments 1 and 2, participants with greater baseball knowledge, regardless of reading skill, more quickly suppressed the irrelevant meaning of ambiguous words in baseball-related, but not general-topic, sentences. Experiment 3 demonstrated that participants with greater general knowledge, regardless of reading skill, more quickly suppressed the irrelevant meaning of the ambiguous words in general-topic sentences. As predicted by D. S. McNamara's (1997) knowledge-based account of suppression, ambiguity effects are influenced by greater activation of knowledge related to the intended meaning of the homograph. These results challenge inhibition (e.g. M. A. Gernsbacher, K. R. Varner. & M. Faust, 1990) as the sole mechanism responsible for the suppression of irrelevant information.     

Hindsight bias: a by-product of knowledge updating?

With the benefit of feedback about the outcome of an event, people's recalled judgments are typically closer to the outcome of the event than their original judgments were. It has been suggested that this hindsight bias may be due to a reconstruction process of the prior judgment. A model of such a process is proposed that assumes that knowledge is updated after feedback and that reconstruction is based on the updated knowledge. Consistent with the model's predictions, the results of 2 studies show that knowledge after feedback is systematically shifted toward feedback, and that assisting retrieval of the knowledge prior to feedback reduces hindsight bias. In addition, the model accounts for about 75% of cases in which either hindsight bias or reversed hindsight bias occurred. The authors conclude that hindsight bias can be understood as a by-product of an adaptive process, namely the updating of knowledge after feedback.