Distributed Knowability and Fitch’s Paradox

Recently predominant forms of anti-realism claim that all truths are knowable. We argue that in a logical explanation of the notion of knowability more attention should be paid to its epistemic part. Especially very useful in such explanation are notions of group knowledge. In this paper we examine mainly the notion of distributed knowability and show its effectiveness in the case of Fitch’s paradox. Proposed approach raised some philosophical questions to which we try to find responses. We also show how we can combine our point of view on Fitch’s paradox with the others. Next we give an answer to the question: is distributed knowability factive? At the end, we present some details concerning a construction of anti-realist modal epistemic logic.     

Introduction: A Systems View

Our goal in this series of four papers is a further refinement of a theory of interaction for psychoanalysis, with a specific focus on the concept of intersubjectivity. Psychoanalysis has addressed the concept of intersubjectivity primarily in the verbal/explicit mode. In contrast, infant research has addressed the concept of intersubjectivity in the nonverbal/implicit mode of action sequences, or procedural knowledge. We propose that an integration of explicit/linguistic with implicit/nonverbal theories of intersubjectivity is essential to a deeper understanding of therapeutic action in psychoanalysis today. To shed light on an implicit/nonverbal dimension of intersubjectivity in psychoanalysis, we include concepts from adult psychoanalysis, infant research, developmental systems theories, and nonverbal communication, particularly the distinction between implicit processing out of awareness and explicit processing at the declarative/verbal level. We conclude with an adult psychoanalytic case illustrating the integration of implicit/nonverbal forms of intersubjectivity into adult treatment.     

Problems for factive accounts of assertion

The knowledge account of assertion construes assertion as subject to constitutive norms. In its standard version, it combines a wide scope obligation not to assert p without knowing p, with narrow scope principles specifying conditions under which it is permissible to assert p, where the notions of obligation and permission are duals and behave uniformly for variable p. It is argued that, given natural assumptions about the logic of ‘ought’, the account proves incoherent. The argument generalizes to accounts that substitute other factive notions for knowledge. A recent non-standard version of the knowledge account employs proposition-relative norms and circumvents the problem. However, it still leads to intolerable combinations of verdicts. Again, the problem arises because knowledge is factive, and it generalizes to other factive notions. It is shown that non-factive accounts face none of the diagnosed difficulties and can do much of the explanatory work that the knowledge account is alleged to do.     

Non‐Classical Knowledge

The Knower paradox purports to place surprising a priori limitations on what we can know. According to orthodoxy, it shows that we need to abandon one of three plausible and widely‐held ideas: that knowledge is factive, that we can know that knowledge is factive, and that we can use logical/mathematical reasoning to extend our knowledge via very weak single‐premise closure principles. I argue that classical logic, not any of these epistemic principles, is the culprit. I develop a consistent theory validating all these principles by combining Hartry Field's theory of truth with a modal enrichment developed for a different purpose by Michael Caie. The only casualty is classical logic: the theory avoids paradox by using a weaker‐than‐classical K₃ logic. I then assess the philosophical merits of this approach. I argue that, unlike the traditional semantic paradoxes involving extensional notions like truth, its plausibility depends on the way in which sentences are referred to—whether in natural languages via direct sentential reference, or in mathematical theories via indirect sentential reference by Gödel coding. In particular, I argue that from the perspective of natural language, my non‐classical treatment of knowledge as a predicate is plausible, while from the perspective of mathematical theories, its plausibility depends on unresolved questions about the limits of our idealized deductive capacities.     

Performing the unexplainable: Implicit task performance reveals individually reliable sequence learning without explicit knowledge

Memory-impaired patients express intact implicit perceptual-motor sequence learning, but it has been difficult to obtain a similarly clear dissociation in healthy participants. When explicit memory is intact, participants acquire some explicit knowledge and performance improvements from implicit learning may be subtle. Therefore, it is difficult to determine whether performance exceeds what could be expected on the basis of the concomitant explicit knowledge. Using a challenging new sequence-learning task, robust implicit learning was found in healthy participants with virtually no associated explicit knowledge. Participants trained on a repeating sequence that was selected randomly from a set of five. On a performance test of all five sequences, performance was best on the trained sequence, and two-thirds of the participants exhibited individually reliable improvement (by chi-square analysis). Participants could not reliably indicate which sequence had been trained by either recognition or recall. Only by expressing their knowledge via performance were participants able to indicate which sequence they had learned.     

When memory fails, intuition reigns: midazolam enhances implicit inference in humans

People often make logically sound decisions using explicit reasoning strategies, but sometimes it pays to rely on more implicit "gut-level" intuition. The transitive inference paradigm has been widely used as a test of explicit logical reasoning in animals and humans, but it can also be solved in a more implicit manner. Some researchers have argued that the hippocampus supports relational memories required for making logical inferences. Here we show that the benzodiazepene midazolam, which inactivates the hippocampus, causes profound explicit memory deficits in healthy participants, but enhances their ability in making implicit transitive inferences. These results are consistent with neurocomputational models of the basal ganglia-dopamine system that learn to make decisions through positive and negative reinforcement. We suggest that disengaging the hippocampal explicit memory system can be advantageous for this more implicit form of learning.     

The time course of implicit and explicit concept learning

The present experiment investigated the development of implicit and explicit knowledge during concept learning. According to Cleeremans and Jiménez (2002), the content of a representation can be conscious only when the representation is of a sufficiently good quality; on this theory, increasing explicit and decreasing implicit knowledge might be expected with training. The view that implicit knowledge arises from compilation of explicit knowledge makes the opposite prediction. The present research tested these possibilities using subjective measures based on confidence ratings. One group of participants was presented with blocks of category exemplars that activated prior knowledge, whereas another group was presented with blocks of categories that did not elicit any useful prior knowledge. The results showed that, irrespective of the knowledge group participants were allocated to, explicit knowledge increased over the course of learning, whereas implicit knowledge either stayed the same or decreased, consistent with Cleeremans and Jiménez's prediction.     

Implicit and explicit processes in a second-language learning task

Abstract

Two experiments examined the learning of a set of Greek pronunciation rules through explicit and implicit modes of rule presentation. Experiment 1 compared the effectiveness of implicit and explicit modes of presentation in two modalities, visual and auditory. Subjects in the explicit or rule group were presented with the rule set, and those in the implicit or natural group were shown a set of Greek words, composed of letters from the rule set, linked to their pronunciations. Subjects learned the Greek words to criterion and were then given a series of tests which aimed to tap different types of knowledge. The results showed an advantage of explicit study of the rules. In addition, an interaction was found between mode of presentation and modality. Explicit instruction was more effective in the visual than in the auditory modality, whereas there was no modality effect for implicit instruction. Experiment 2 examined a possible reason for the advantage of the rule groups by comparing different combinations of explicit and implicit presentation in the study and learning phases. The results suggested that explicit presentation of the rules is only beneficial when it is followed by practice at applying them.     

L’entraînement cognitivo-perceptif basé sur la vidéo et ses modes d’instructions

This literature review examines both the effectiveness of simulation training video to improve decision-making of athletes and secondly, the benefits of explicit, implicit and guided instructions used during video-based perceptual training. Thus, it is shown that video-based perceptual training improves cognitive and perceptual skills resulting in decrease in decision time and increase in decision's accuracy in simulations and field. Furthermore, the benefits of explicit approaches in early stage of learning to promote rapid acquisition of knowledge is highlighted. On the other hand, it is suggested that implicit approaches will be more conducive to the experts to ensure that they “reinvest” their knowledge in stressful situations. Finally, it is envisaged that guided approaches are relevant alternatives to explicit and implicit approaches.     

Children's linguistic intuitions about factive presuppositions

Third and sixth graders' understanding of factive presupposition was investigated via two tasks: One required an abstract truth value judgment of the verb complement; the other called for a more informal judgment of consistency (or contradiction) between the target sentence and the negation of its complement. When compared with corresponding adult data, the present results indicate that the development of factive presupposition continues through late childhood. A further task examined a nonlogical pragmatic variable related to factive meaning. The final task investigated whether children's judgments of overall certainty are governed by factive or pragmatic aspects of meaning. Comparisons across the four tasks indicate that factive presupposition only gradually emerges as a distinct logical component of verb meaning. It is argued that young children's initial discriminations between factive and nonfactive verbs reflect the subjective confidence conveyed by the verb rather than the logical property of factivity, but that later in acquisition, factivity acquires a status superseding that of other facets of meaning.     

The neural correlates of implicit and explicit sequence learning: Interacting networks revealed by the process dissociation procedure

In two H2(15)O PET scan experiments, we investigated the cerebral correlates of explicit and implicit knowledge in a serial reaction time (SRT) task. To do so, we used a novel application of the Process Dissociation Procedure, a behavioral paradigm that makes it possible to separately assess conscious and unconscious contributions to performance during a subsequent sequence generation task. To manipulate the extent to which the repeating sequential pattern was learned explicitly, we varied the pace of the choice reaction time task-a variable that is known to have differential effects on the extent to which sensitivity to sequence structure involves implicit or explicit knowledge. Results showed that activity in the striatum subtends the implicit component of performance during recollection of a learned sequence, whereas the anterior cingulate/mesial prefrontal cortex (ACC/MPFC) supports the explicit component. Most importantly, we found that the ACC/MPFC exerts control on the activity of the striatum during retrieval of the sequence after explicit learning, whereas the activity of these regions is uncoupled when learning had been essentially implicit. These data suggest that implicit learning processes can be successfully controlled by conscious knowledge when learning is essentially explicit. They also supply further evidence for a partial dissociation between the neural substrates supporting conscious and nonconscious components of performance during recollection of a learned sequence.     

The emergence of explicit knowledge during the early phase of learning in sequential reaction time tasks

Five experiments investigated the formation of explicit knowledge of a repeating sequence in a sequential reaction time task. Reliable explicit knowledge was obtained even though various conditions prevented the selective improvement of RTs (Exps. 1–4). This knowledge emerged early during training. Participants were able to recognize segments of the sequence (Exps. 3 and 4) or correctly assess the probabilities of transition of the target between successive locations (Exp. 5) after only two blocks of training trials. These findings rule out an interpretation of sequence learning that posits that explicit knowledge emerges from implicit knowledge during the course of training. Although these findings are compatible with a framework centered around the notion of dissociation between implicit and explicit knowledge, they are also consonant with a questioning of the usefulness of the concept of implicit knowledge.     

Accidentally Factive Mental States

Knowledge is standardly taken to be belief that is both true and justified (and perhaps meets other conditions as well). Timothy Williamson rejects the standard epistemology for its inability to solve the Gettier problem. the moral of this failure, he argues, is that knowledge does not factor into a combination that includes a mental state (belief) and an external condition (truth), but is itself a type of mental state. Knowledge is, according to his preferred account, the most general factive mental state. I argue, however, that Gettier cases pose a serious problem for Williamson's epistemology: in these cases, the subject may have a factive mental state that fails to be cognitive. Hence, knowledge cannot be the most general factive mental state.     

Implicit Learning and Concept Learning

In Experiments 1 and 2, subjects were exposed to letter strings that followed a pattern—the second letter was always the same. This exposure was disguised as a test of immediate memory. Following this training, subjects could discriminate new letter strings following the pattern from letter strings not following the pattern more often than would be expected by chance, which is the traditional evidence for concept learning. Discrimination was also better than would be predicted from subjects' explicit report of the pattern, demonstrating the co-occurrence of concept learning and implicit learning. In Experiment 3, rules were learned explicitly. Discrimination was worse than would be predicted from subjects' explicit report, validating the implicit learning paradigm. In Experiment 4, deviations from a prototypical pattern were presented during training. In the test of discrimination, prototypes were as familiar as old deviations and more familiar than new deviations, even when considering only implicit knowledge. Experiment 5 found implicit knowledge of a familiar concept. These results are consistent with the hypothesis that the distinguishing features of a concept can be learned implicitly, and that one type of implicit learning is concept learning.     

The Relation Between Implicit and Explicit Learning: Evidence for Parallel Development

Much research has focused on the separability of implicit and explicit learning, but less has focused on how they might interact. A recent model suggests that in the motor-skill domain, explicit knowledge can guide movement, and the implicit system learns in parallel, based on these movements. Functional imaging studies do not support that contention, however; they indicate that learning is exclusively implicit or explicit. In the experiment reported here, participants learned a motor sequencing task either implicitly or explicitly. At transfer, most of the stimuli were random, but the sequence occasionally appeared; thus, it was not obvious that explicit knowledge could be applied to the task. Nevertheless, participants with explicit training showed sequence knowledge equivalent to those with implicit training, implying that implicit knowledge had been acquired in parallel with explicit knowledge. This result has implications for the development of automaticity and of motor-skill learning.     

Restricting factiveness

In discussions of Fitch’s paradox, it is usually assumed without further argument that knowledge is factive, that if a subject knows that p, then p is true. It is argued that this common assumption is not as well-founded as it should be, and that there in fact are certain reasons to be suspicious of the unrestricted version of the factiveness claim. There are two kinds of reason for this suspicion. One is that unrestricted factiveness leads to paradoxes and unexpected results, the other is that the usual arguments for factiveness are not as compelling as is commonly thought. There may in fact be some kinds of contexts, where factiveness doesn’t hold for knowledge—the usual arguments for factiveness don’t suffice to support the claim that knowledge is unrestrictedly factive. Perhaps all that can be shown is that knowledge is at times factive, or that it is default factive, as it were: this doesn’t show that there can’t be counterexamples, however. Certain aspects of knowledge without unrestricted factiveness are examined briefly.     

分次模态传递框架类(英文)

本文证明分次模态逻辑在有穷传递框架类中的Goldblatt-Thomason定理。一个有穷传递框架类可由分次模态公式集定义当且仅当它在不相交并、生成子框架和分次有界态射像下封闭。该定理的证明使用带根的有穷传递框架的分次Jankov-Fine公式。     

Subjective Situations and Logical Omniscience

The beliefs of the agents in a multi-agent system have been formally modelled in the last decades using doxastic logics. The possible worlds model and its associated Kripke semantics provide an intuitive semantics for these logics, but they commit us to model agents that are logically omniscient. We propose a way of avoiding this problem, using a new kind of entities called subjective situations. We define a new doxastic logic based on these entities and we show how the belief operators have some desirable properties, while avoiding logical omniscience. A comparison with two well-known proposals (Levesque's logic of explicit and implicit beliefs and Thijsse's hybrid sieve systems) is also provided.     

Interference produces different forgetting rates for implicit and explicit knowledge

Exposure to a repeating set of target strings generated by an artificial grammar in a speeded matching task generates both explicit and implicit knowledge. Previous research has shown that implicit knowledge (assessed via a priming measure) is preserved after a retention interval of one week but explicit knowledge (assessed via recognition) is significantly reduced. In two experiments, we replicated and extended Tunney's findings. Experiment 1 was a partial replication of the experiment conducted by Tunney, and demonstrated that the decline in recognition shown by Tunney was not due to a repetition of test items at the pre and post times of assessment. In addition, Experiment 1 lends credibility to Tunney's assumption that recognition scores assess explicit rather than implicit knowledge. Experiment 2 extended Tunney's findings theoretically by demonstrating that interference can produce the pattern of findings demonstrated in the present Experiment 1 as well as in Tunney.