The Church–Fitch knowability paradox in the light of structural proof theory

Anti-realist epistemic conceptions of truth imply what is called the knowability principle: All truths are possibly known. The principle can be formalized in a bimodal propositional logic, with an alethic modality ${\diamondsuit}$ and an epistemic modality ${\mathcal{K}}$ , by the axiom scheme ${A \supset \diamondsuit \mathcal{K} A}$ (KP). The use of classical logic and minimal assumptions about the two modalities lead to the paradoxical conclusion that all truths are known, ${A \supset \mathcal{K} A}$ (OP). A Gentzen-style reconstruction of the Church–Fitch paradox is presented following a labelled approach to sequent calculi. First, a cut-free system for classical (resp. intuitionistic) bimodal logic is introduced as the logical basis for the Church–Fitch paradox and the relationships between ${\mathcal {K}}$ and ${\diamondsuit}$ are taken into account. Afterwards, by exploiting the structural properties of the system, in particular cut elimination, the semantic frame conditions that correspond to KP are determined and added in the form of a block of nonlogical inference rules. Within this new system for classical and intuitionistic “knowability logic”, it is possible to give a satisfactory cut-free reconstruction of the Church–Fitch derivation and to confirm that OP is only classically derivable, but neither intuitionistically derivable nor intuitionistically admissible. Finally, it is shown that in classical knowability logic, the Church–Fitch derivation is nothing else but a fallacy and does not represent a real threat for anti-realism.     

Running with emotion: When affective content hampers working memory performance

This study tested the hypothesis that affective content may undermine rather than facilitate working memory (WM) performance. To this end, participants performed a running WM task with positive, negative and neutral words. In typical running memory tasks, participants are presented with lists of unpredictable length and are asked to recall the last three or four items. We found that accuracy with affective words decreased as lists lengthened, whereas list length did not influence recall of neutral words. We interpreted this pattern of results in terms of a limited resource model of WM in which valence represents additional information that needs to be manipulated, especially in the context of difficult trials.     

I See Not Only a Madonna,but Also a Hole,in the Picture

According to an intuitive claim, in saying that one sees a picture's subject, i.e., what a picture presents, in the picture's vehicle, i.e., the picture's physical basis, by ‘in’ one does not mean the spatial relation of being in, as holding between such items in the real space. For the picture's subject is knowingly not in the real space where one veridically sees the picture's vehicle. Some theories of pictorial experience have actually agreed with this intuition by claiming that the picture's subject lies in a pictorial space of its own, disconnected from the real space that includes the picture's vehicle. Yet, not only linguistic evidence suggests that when used as above, ‘in’ means precisely that very relation, but an appropriate theory of pictorial experience can justify the above claim.     

Can small lesions induce language reorganization as large lesions do?

Shift of the cortical mechanisms of language from the usually dominant left to the non-dominant right hemisphere has been demonstrated in the presence of large brain lesions. Here, we report a similar phenomenon in a patient with a cavernoma over the anterolateral superior temporal gyrus associated with epilepsy. Language mapping was performed by two complementary procedures, magnetoencephalography, and electrocorticography. The maps, indicated right temporal lobe dominance for receptive language and left frontal lobe dominance for expressive language. These results indicate that a small lesion, associated with epilepsy, may produce selective shifting of receptive language mechanisms as large lesions have been known to produce.     

Attitude to primary prevention advice of the European Code against cancer in relatives of cancer patients: implications for the development of preventive programmes

Achieving a preventive attitude is the first step in eliminating cancer risk behaviours. This cross-sectional study evaluated the attitude towards the European Code against Cancer, in 3,031 relatives of cancer patients. The study looked for keys to improve attitude by means of educational interventions. Attitude was evaluated using a questionnaire with 63 items and a Likert's scale. Measured from -2 to +2 , the mean score was 0.905 [0.894 - 0.971]. Five per cent had a mean score under 0.38 and another 5% over 1.46. A multivariate analysis found that age, sex and level of education were significantly associated with attitude: young men with a low cultural level were those with the lowest preventive attitude. The family history of cancer was not associated with attitude. Educational interventions should modify the perceived advantages of smoking and drinking, and the disadvantages related to preventive diet and sun and workplace protection.     

A theory of sulcal-gap signalization

Two sulcal-gap signalization systems are hypothesized to have evolved as emergent functional "exaptations" having the capacity to transmit two-way cortex-to-cortex signals across tissues embedded in opposing sulcal banks. Hypothesis 1 posits that a primary sulcal-gap signalization system evolved the capacity to transmit nonlanguage signals within hierarchically lower-order sensory, motor, and perceptual functional areas of the neocortex having elemental functional units consisting of columns of about 110 neurons. Hypothesis 2 posits that a secondary sulcal-gap signalization system evolved the capacity to transmit language signals within hierarchically higher-order cognitive functional areas of the "neo-neocortex" having elemental functional units consisting of modules of about 4,000 neurons. Neuroanatomical, neurophysiological neuroevolutionary, and neurodevelopmental evidence is presented in support of these two sulcal-gap hypotheses. It is speculated that the combined cognitive capacities of these two sulcal-gap signalization systems may contribute to the transduction of physiological brain into psychological mind.     

Effects of speed and accuracy strategy on choice step execution in response to the flanker interference task

The purpose of this study is to examine the effects of a speed or accuracy strategy on response interference control during choice step execution. Eighteen healthy young participants were instructed to execute forward stepping on the side indicated by a central arrow (←, left vs. →, right) under task instructions that either emphasized speed or accuracy of response in the neutral condition. In the flanker condition, they were additionally required to ignore the 2 flanking arrows on each side (→→→→→, congruent or →→←→→, incongruent). Errors in the direction of the initial weight transfer (APA errors) and the step execution times were measured from the vertical force data. APA error was increased in response to the flanker task and step execution time was shortened with a speed strategy compared to an accuracy strategy. Furthermore, in response to the visual interference of the flanker task, speed instructions in particular increased APA errors more than other instructions. It may be important to manipulate the level of the speed-accuracy trade-off to improve efficiency and safety. Further research is needed to explore the effects of advancing age and disability on choice step reaction in a speed or accuracy strategy.     

The Correlation Between Right-Wing Authoritarianism and Social Dominance Orientation: The Moderating Effects of Political and Religious Identity

In a secondary analysis performed on a representative sample of the Italian population (N = 887), we examined the correlation between right-wing authoritarianism (RWA) and social dominance orientation (SDO), analyzing the moderating effect exerted on such correlation by political interest and religion importance. RWA and SDO showed a positive, significant correlation (r = .38), moderated by political interest (which heightened it) and religion importance (which lowered it). Limits, implications, and possible developments of the research are discussed.