The Undecidability of Quantified Announcements

This paper demonstrates the undecidability of a number of logics with quantification over public announcements: arbitrary public announcement logic (APAL), group announcement logic (GAL), and coalition announcement logic (CAL). In APAL we consider the informative consequences of any announcement, in GAL we consider the informative consequences of a group of agents (this group may be a proper subset of the set of all agents) all of which are simultaneously (and publicly) making known announcements. So this is more restrictive than APAL. Finally, CAL is as GAL except that we now quantify over anything the agents not in that group may announce simultaneously as well. The logic CAL therefore has some features of game logic and of ATL. We show that when there are multiple agents in the language, the satisfiability problem is undecidable for APAL, GAL, and CAL. In the single agent case, the satisfiability problem is decidable for all three logics.     

Social Externalism and Conceptual Errors

I offer a defence of individualism by critically examining the preconditions of Tyler Burge's famous thought-experiment involving the concept of arthritis. I argue that the thought-experiment relies on a problematic notion of conceptual error, one of which Burge himself should be critical, given his Quinean commitments. Once this misstep in the experiment is made explicit, individualism emerges as a much stronger position than it is usually taken to be. Questioning the assumption that the patient uttering 'I have arthritis in my thigh' makes a conceptual error makes it possible for the individualist to grant Burge the claim that the patient has the standard concept of arthritis, rather than his own deviant concept, and yet avoid the social externalist conclusions.     

Working memory deficits in transgenic rats overexpressing human adenosine A2A receptors in the brain

Adenosine receptors in the central nervous system have been implicated in the modulation of different behavioural patterns and cognitive functions although the specific role of A(2A) receptor (A(2A)R) subtype in learning and memory is still unclear. In the present work we establish a novel transgenic rat strain, TGR(NSEhA2A), overexpressing adenosine A(2A)Rs mainly in the cerebral cortex, the hippocampal formation, and the cerebellum. Thereafter, we explore the relevance of this A(2A)Rs overexpression for learning and memory function. Animals were behaviourally assessed in several learning and memory tasks (6-arms radial tunnel maze, T-maze, object recognition, and several Morris water maze paradigms) and other tests for spontaneous motor activity (open field, hexagonal tunnel maze) and anxiety (plus maze) as modification of these behaviours may interfere with the assessment of cognitive function. Neither motor performance and emotional/anxious-like behaviours were altered by overexpression of A(2A)Rs. TGR(NSEhA2A) showed normal hippocampal-dependent learning of spatial reference memory. However, they presented working memory deficits as detected by performance of constant errors in the blind arms of the 6 arm radial tunnel maze, reduced recognition of a novel object and a lack of learning improvement over four trials on the same day which was not observed over consecutive days in a repeated acquisition paradigm in the Morris water maze. Given the interdependence between adenosinic and dopaminergic function, the present results render the novel TGR(NSEhA2A) as a putative animal model for the working memory deficits and cognitive disruptions related to overstimulation of cortical A(2A)Rs or to dopaminergic prefrontal dysfunction as seen in schizophrenic or Parkinson's disease patients.     

Is Understanding Epistemic in Nature?

Is understanding epistemic in nature? Does a correct account of what constitutes understanding of a concept mention epistemological notions such as knowledge, justification or epistemic rationality? We defend the view that understanding is epistemic in nature – we defend epistemological conceptions of understanding. We focus our discussion with a critical evaluation of Tim Williamson's challenges to epistemological conceptions of understanding in The Philosophy of Philosophy. Against Williamson, we distinguish three kinds of epistemological conceptions and argue that Williamson's arguments succeed against only the most heavily committed kind, and leave the less heavily committed kinds untouched. Further, we argue that Williamson's elaboration of lessons from his arguments point in a direction opposite of his own conclusions and give vivid articulation and support to epistemological conceptions. We suggest also that skepticism about Williamson's larger metaphilosophical conclusions – according to which understanding plays no special role in the epistemology of philosophy – may be in order.     

A mediation analysis of achievement motives,goals, learning strategies,and academic achievement

Background. Previous research is inconclusive regarding antecedents and consequences of achievement goals, and there is a need for more research in order to examine the joint effects of different types of motives and learning strategies as predictors of academic achievement. Aims. To investigate the relationship between achievement motives, achievement goals, learning strategies (deep, surface, and strategic), and academic achievement in a hierarchical model. Sample. Participants were 229 undergraduate students (mean age: 21.2 years) of psychology and economics at the University of Bergen, Norway. Methods. Variables were measured by means of items from the Achievement Motives Scale (AMS), the Approaches and Study Skills Inventory for Students, and an achievement goal scale. Results. Correlation analysis showed that academic achievement (examination grade) was positively correlated with performance‐approach goal, mastery goal, and strategic learning strategies, and negatively correlated with performance‐avoidance goal and surface learning strategy. A path analysis (structural equation model) showed that achievement goals were mediators between achievement motives and learning strategies, and that strategic learning strategies mediated the relationship between achievement goals and academic achievement. Conclusions. This study integrated previous findings from several studies and provided new evidence on the direct and indirect effects of different types of motives and learning strategies as predictors of academic achievement.     

Infelicitous Cancellation: The Explicit Cancellability Test for Conversational Implicature Revisited

This paper questions the adequacy of the explicit cancellability test for conversational implicature as it is commonly understood. The standard way of understanding this test relies on two assumptions: first, that that one can test whether a certain content is (merely) conversationally implicated, by checking whether that content is cancellable, and second, that a cancellation is successful only if it results in a felicitous utterance. While I accept the first of these assumptions, I reject the second one. I argue that a cancellation can succeed even if it results in an infelicitous utterance, and that unless we take this possibility into account we run the risk of misdiagnosing philosophically significant cases.     

The combined influence of hardiness and cohesion on mental health in a military peacekeeping mission: A prospective study

A large number of studies have shown that hardiness and cohesion are associated with mental health in a military context. However, most of them are presented without controlling for baseline mental health symptoms, which is their most significant source of error. The present study investigates the combined effect of hardiness and cohesion in a prospective design, controlling for baseline levels of symptoms among Norwegian personnel serving in a peacekeeping operation in Kosovo. Multivariate regression analyses were performed in which self‐reported mental health complaints were regressed on our explanatory variables. Our findings suggest that both cohesion and hardiness contributed to increased stress resiliency, as measured by a lower level of reported mental health complaints. Our baseline measure of mental health accounted for a larger proportion of the variance than our other predictors. A significant interaction between cohesion and hardiness suggested a combined effect, over and above the individual contributions of the predictors. For individuals who scored high on hardiness, cohesion levels did not influence levels of mental health complaints. Individuals who scored low on hardiness, on the other hand, reported lower levels of mental health complaints when cohesion levels were high.     

The effect of hardiness on PTSD symptoms: A prospective mediational approach

Psychological hardiness has been associated with lower PTSD in military personnel, but the processes of action remain unclear. This study uses a prospective design to examine whether hardiness has an indirect effect on PTSD symptoms through avoidance coping. Our sample included 163 Norwegian military personnel who served in international operations between 2009 and 2010. Regression analyses were performed to estimate the coefficients in a simple mediation model, with baseline PTSD symptoms, combat exposure, and deprivation of basic needs entered as control variables. The results showed that the effect of hardiness on PTSD symptoms worked through reducing the use of avoidance coping. It was concluded that an avoidant-focused coping style acts as a vulnerability factor for PTSD symptoms, whereas hardiness acts as a resilience factor against symptoms development.