We give an account of the appearance and first developments of the statistical model of atoms proposed by Thomas and Fermi, focusing on the main results achieved by Fermi and his group in Rome. Particular attention is addressed to the unknown contribution to this subject by Majorana, anticipating some important results reached later by leading physicists.

In the centennial of Ettore Majorana’s birth (1906–1938?), we re-examine some aspects of his fundamental scientific production in atomic and molecular physics, including a not well known short communication. There, Majorana critically discusses Fermi’s solution of the celebrated Thomas–Fermi equation for electron screening in atoms and positive ions. We argue that some of Majorana’s seminal contributions in molecular physics already prelude to the idea of exchange interactions (or Heisenberg–Majorana forces) in his later works on theoretical nuclear physics. In all (...) his papers, he tended to emphasize the symmetries at the basis of a physical problem, as well as the limitations, rather than the advantages, of the approximations of the method employed. (shrink)

Julian Schwinger was one of the leading theoretical physicists of the twentieth century. His contributions are as important, and as pervasive, as those of Richard Feynman, with whom he shared the 1965 Nobel Prize for Physics. Yet, while Feynman is universally recognized as a cultural icon, Schwinger is little known even to many within the physics community. In his youth, Julian Schwinger was a nuclear physicist, turning to classical electrodynamics after World War II. In the years after the war, he (...) was the first to renormalize quantum electrodynamics. Subsequently, he presented the most complete formulation of quantum field theory and laid the foundations for the electroweak synthesis of Glashow, Weinberg, and Salam, and he made fundamental contributions to the theory of nuclear magnetic resonance, to many-body theory, and to quantum optics. He developed a unique approach to quantum mechanics, measurement algebra, and a general quantum action principle. His discoveries include 'Feynman's' parameters and 'Glauber's' coherent states; in later years he also developed an alternative to operator field theory which he called Source Theory, reflecting his profound phenomenological bent. His late work on the Thomas-Fermi model of atoms and on the Casimir effect continues to be an inspiration to a new generation of physicists. This biography describes the many strands of his research life, while tracing the personal life of this private and gentle genius. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:The Trinity by Thomas Joseph White, O.P.:A Model of Living ThomismSerge-Thomas Bonino O.P."The human being naturally seeks wisdom." From the very first line of the magisterial work we are dealing with, Fr. Thomas Joseph White's 2022 The Trinity: On the Nature and Mystery of the One God, it is all about wisdom. Wisdom was already at the heart of a previous work by Fr. White devoted to the (...) natural theology of St. Thomas, his 2009 Wisdom in the Face of Modernity. Wisdom is more than the accumulation of information or the juxtaposition of knowledge. It is an eminent form of knowledge that, on the one hand, involves the person of the thinker in all its dimensions, intellectual, emotional, existential, and on the other, seeks to understand its object in the light of the most fundamental causes, which are simultaneously the most enlightening and explanatory principles because they are the most universal. The Trinity: On the Nature and Mystery of the One God is undoubtedly a work of wisdom. Fr. White grasps the entire Christian mystery from its Trinitarian source, since, as we shall see, the entire Mystery (in the Pauline sense of the economy of salvation in Jesus Christ as the fulfillment of the Father's benevolent purpose) is at the same time rooted in the eternal mystery of the triune God and makes it known to us as it unfolds its truth and saving power in time.But the sapiential nature of the object studied has some effect on the form of the work itself. Indeed, if Fr. White were not Rector Magnificent of the Angelicum, he would be a magnificent architect, because he possesses a sense of order to the highest degree and knows how to introduce unity in diversity. The presentation of The Trinity is perfectly structured, and therefore very [End Page 461] clear and didactic. Among many other factors that create its unity, I was especially interested in the highlighting of what the philosopher André de Muralt calls "structures of thought": similarities of proportionality between the ways in which authors from even very different theological epochs have treated a problem.1 I am thinking for instance of how Fr. White shows the strong structural similarities between contemporary Trinitarian theologies and the three types of medieval Trinitarian theology (the Franciscan, the Thomist, and the Nominalist). "My claim here is that the modern Trinitarian tradition tends to reproduce various elements of the medieval traditions, … albeit in creative and unexpected ways" (399). So it is a conceptually well-unified work, and where there is unity, there is being, goodness and beauty.The introduction, as I said, is placed under the sign of wisdom. Fr. White takes up there the neo-Scholastic theme of the "three wisdoms": philosophical wisdom, theological wisdom, and mystical wisdom.2 The book's perspective is explicitly that of theological wisdom, as a scientific form of the intelligence of faith, but (we shall return to this point in connection with the place given to philosophy) it puts into practice in an exemplary manner the collaboration, without confusion or separation, between the three wisdoms.3My purpose, of course, is not, nor can it be, to "summarize" the contents of a book of more than seven hundred pages, which manages to be both a comprehensive handbook for higher theological education and a true personal theological essay. I will therefore limit myself to highlighting three partial but significant aspects.(1) The first is the explicit and overt Thomistic character of the book (see 6–7). The Trinity is in fact a vibrant plea in favor of the relevance of the theology of St. Thomas, as indicated by the very last sentence:The Church today can and should still have recourse to the theology of Thomas Aquinas, and to the living Thomistic tradition, as a privileged means of interpreting and advancing her own understanding of the mystery of God.(690) [End Page 462]The Trinity is the demonstration in actu exercito of the truth of this concluding statement. I therefore propose to reflect, in the first part of my paper, on the nature of Fr. White's Thomism, which depends, as we... (shrink)

The self/non-self model, first proposed by F.M. Burnet, has dominated immunology for 60 years now. According to this model, any foreign element will trigger an immune reaction in an organism, whereas endogenous elements will not, in normal circumstances, induce an immune reaction. In this paper we show that the self/non-self model is no longer an appropriate explanation of experimental data in immunology, and that this inadequacy may be rooted in an excessively strong metaphysical conception of biological identity. (...) We suggest that another hypothesis, one based on the notion of continuity, gives a better account of immune phenomena. Finally, we underscore the mapping between this metaphysical deflation from self to continuity in immunology and the philosophical debate between substantialism and empiricism about identity. (shrink)

The individual informed consent model remains critical to the ethical conduct and regulation of research involving human beings. Parental informed consent process in a rural setting of northern Ghana was studied to describe comprehension and retention among parents as part of the evaluation of the existing informed consent process.

This paper intends to further the understanding of the formal properties of (higher-order) vagueness by connecting theories of (higher-order) vagueness with more recent work in topology. First, we provide a “translation” of Bobzien's account of columnar higher-order vagueness into the logic of topological spaces. Since columnar vagueness is an essential ingredient of her solution to the Sorites paradox, a central problem of any theory of vagueness comes into contact with the modern mathematical theory of topology. Second, Rumfitt’s recent topological reconstruction (...) of Sainsbury’s theory of prototypically defined concepts is shown to lead to the same class of spaces that characterize Bobzien’s account of columnar vagueness, namely, weakly scattered spaces. Rumfitt calls these spaces polar spaces. They turn out to be closely related to Gärdenfors’ conceptual spaces, which have come to play an ever more important role in cognitive science and related disciplines. Finally, Williamson’s “logic of clarity” is explicated in terms of a generalized topology (“locology”) that can be considered an alternative to standard topology. Arguably, locology has some conceptual advantages over topology with respect to the conceptualization of a boundary and a borderline. Moreover, in Williamson’s logic of clarity, vague concepts with respect to a notion of a locologically inspired notion of a “slim boundary” are (stably) columnar. Thus, Williamson’s logic of clarity also exhibits a certain affinity for columnar vagueness. In sum, a topological perspective is useful for a conceptual elucidation and unification of central aspects of a variety of contemporary accounts of vagueness. (shrink)

The notion of a D-ring, generalizing that of a differential or a difference ring, is introduced. Quantifier elimination and a version of the Ax-Kochen-Eršov principle is proven for a theory of valued D-fields of residual characteristic zero.

This paper introduces a class of graphical independence models that is closed under marginalization and conditioning but that contains all DAG independence models. This class of graphs, called maximal ancestral graphs, has two attractive features: there is at most one edge between each pair of vertices; every missing edge corresponds to an independence relation. These features lead to a simple parameterization of the corresponding set of distributions in the Gaussian case.

A probabilistic Chomsky–Schützenberger hierarchy of grammars is introduced and studied, with the aim of understanding the expressive power of generative models. We offer characterizations of the distributions definable at each level of the hierarchy, including probabilistic regular, context-free, (linear) indexed, context-sensitive, and unrestricted grammars, each corresponding to familiar probabilistic machine classes. Special attention is given to distributions on (unary notations for) positive integers. Unlike in the classical case where the "semi-linear" languages all collapse into the regular languages, using analytic tools (...) adapted from the classical setting we show there is no collapse in the probabilistic hierarchy: more distributions become definable at each level. We also address related issues such as closure under probabilistic conditioning. (shrink)

The notion of a D-ring, generalizing that of a differential or a difference ring, is introduced. Quantifier elimination and a version of the Ax-Kochen-Ersov principle is proven for a theory of valued D-fields of residual characteristic zero.

In “Getting that Model T Back on the Road: Thomas Flint on Incarnation and Mereology,” William Hasker contends that the reasons I offered for being dissatisfied with Model T, a mereological model of the incarnation, are insufficient. I argue, though, that Hasker’s defense of Model T is inadequate; though Christians may not want to consign it to the junkyard, they should at least be open to trading it in for a better model.

There is a rough, long-term tradeoff between rate of innovation and degree of strong realism in scientific practice, a point reflected in historically changing conceptions of method as they retreat from epistemological foundationism to a highly fallibilistic, modeling perspective. The successively more liberal, innovation-stimulating methods open up to investigation deep theoretical domains at the cost, in many cases, of moving away from strong realism as a likely outcome of research. The crowbar model of method highlights this tension, expressed as (...) the crowbar compromise and the crowbar fallacy. The tools-to-theories heuristic, described and evaluated by Gigerenzer and colleagues, can be regarded as an attempt by some scientific realists to overcome this compromise. Instead, it is an instance of it. Nonetheless, in successful applications the crowbar model implies a modest, instrumental (nonrepresentational) realism. (shrink)

It describes and explains the patient-centered model examining and evaluating qualitative and quantitative research. It comprehensively covers the evolution and the six interactive components of the patient-centered clinical method, taking the reader through the relationships between the patient and doctor and the patient and clinician. All the editors are professors in the Department of Family Medicine at the University of Western Ontario, London, Canada.

As a way to address both ominous and ordinary threats of artificial intelligence, researchers have started proposing ways to stop an AI system before it has a chance to escape outside control and cause harm. A so-called “big red button” would enable human operators to interrupt or divert a system while preventing the system from learning that such an intervention is a threat. Though an emergency button for AI seems to make intuitive sense, that approach ultimately concentrates on the point (...) when a system has already “gone rogue” and seeks to obstruct interference. A better approach would be to make ongoing self-evaluation and testing an integral part of a system’s operation, diagnose how the system is in error and to prevent chaos and risk before they start. In this paper, we describe the demands that recent big red button proposals have not addressed, and we offer a preliminary model of an approach that could better meet them. We argue for an ethical core that consists of a scenario-generation mechanism and a simulation environment that are used to test a system’s decisions in simulated worlds, rather than the real world. This EC would be kept opaque to the system itself: through careful design of memory and the character of the scenario, the system’s algorithms would be prevented from learning about its operation and its function, and ultimately its presence. By monitoring and checking for deviant behavior, we conclude, a continual testing approach will be far more effective, responsive, and vigilant toward a system’s learning and action in the world than an emergency button which one might not get to push in time. (shrink)

We present a formal, mathematical model of argument structure and evaluation, taking seriously the procedural and dialogical aspects of argumentation. The model applies proof standards to determine the acceptability of statements on an issue-by-issue basis. The model uses different types of premises (ordinary premises, assumptions and exceptions) and information about the dialectical status of statements (stated, questioned, accepted or rejected) to allow the burden of proof to be allocated to the proponent or the respondent, as appropriate, for (...) each premise separately. Our approach allows the burden of proof for a premise to be assigned to a different party than the one who has the burden of proving the conclusion of the argument, and also to change the burden of proof or applicable proof standard as the dialogue progresses from stage to stage. Useful for modeling legal dialogues, the burden of production and burden of persuasion can be handled separately, with a different responsible party and applicable proof standard for each. Carneades enables critical questions of argumentation schemes to be modeled as additional premises, using premise types to capture the varying effect on the burden of proof of different kinds of questions. (shrink)

Cette étude essaye d’établir qu’il y a deux notions très différentes de « fondation » à l’œuvre dans les Recherches logiques de Husserl. Dans la IIIème Recherche, où le terme est formellement introduit, lorsqu’il se demande quels sont les contenus qui peuvent exister d’une manière autonome (indépendants) et lesquels peuvent exister uniquement en tant que moments d’autre chose (dépendants), Husserl suit ce que j’appelle un « modèle ontologique ». Selon ce modèle, le concret possède une priorité sur à l’abstrait qui (...) est fondé en lui. Dans la VIème Recherche, en revanche, Husserl s’oriente principalement sur un « modèle gnoséologique » qui voit le complexe comme fondé sur ce qui est relativement simple, étant donné que les expériences d’ordre supérieur (telles les perceptions de types d’objets plus complexes) sont « fondées sur » des expériences plus simples, bien qu’elles ne puissent pas y être réduites. L’exemple principal ici est celui des intuitions catégoriales : fondées sur les intuitions sensibles, elles n’y sont pas réductibles. Mais cette distinction entre deux sens différents du terme de « fondation » peut également nous aider à mieux comprendre de nombreuses thèses husserliennes plutôt controversées. Par exemple, elle peut nous permettre de mieux comprendre dans quelle mesure faire l’expérience d’un être humain comme un tout se fonde sur l’expérience d’un corps physique, et cela même si l’étant que nous rencontrons inclut à la fois des aspects corporels et des aspects spirituels – les deux étant vus, d’une manière essentielle, comme des moments de cette unique personne qui fait l’objet de notre expérience. (shrink)

People with a repressive coping style are highly motivated to defend themselves against self-concept threats. But what kinds of unfavourable personal characteristics are they most focused on avoiding? Weinberger (Citation1990) suggested that repressors are primarily concerned with seeing themselves (and having others see them) as calm, unemotional people who are not prone to experiencing negative affect. A content analysis of the actual (self-ascribed) and undesired attributes of 349 male and female college students, however, provided no support for that hypothesis. Instead, (...) relative to other participants, repressors’ undesired selves consisted more of traits exemplifying disagreeableness (as defined by the five-factor model). Repressors might not engage in affective self-regulation for its own sake, but because it allows them to control expression of traits with which they are more directly concerned. (shrink)

Our minds have physical effects. This happens, for instance, when we move our bodies when we act. How is this possible? Thomas Kroedel defends an account of mental causation in terms of difference-making: if our minds had been different, the physical world would have been different; therefore, the mind causes events in the physical world. His account not only explains how the mind has physical effects at all, but solves the exclusion problem - the problem of how those effects can (...) have both mental and physical causes. It is also unprecedented in scope, because it is available to dualists about the mind as well as physicalists, drawing on traditional views of causation as well as on the latest developments in the field of causal modelling. It will be of interest to a range of readers in philosophy of mind and philosophy of science. This book is also available as Open Access. (shrink)

This paper discusses contemporary advancements in the affective sciences that can inform the music-emotion literature. Key concepts in these theories are outlined, highlighting their points of agreement and disagreement. This summary shows the importance of appraisal within the emotion process, provides a greater emphasis upon goal-directed accounts of behavior, and a need to move away from discrete emotion “folk” concepts and toward the study of an emotional episode and its components. Consequently, three contemporary music emotion theories are examined through a (...) skeptical lens. This critique highlights the over-reliance upon categorization and a lack of acknowledgment of appraisal processes, specifically goal-directed appraisal, in examining how individual experiences of music emerge in different contexts. Based on this critique of current music-emotion models, we present our skeptically informed CODA model - Constructivistly-Organised Dimensional-Appraisal model. This model addresses skeptical limitations of existing theories, reinstates the role of goal-directed appraisal as central to what makes music relevant and meaningful to an individual in different contexts and brings together different theoretical frameworks into a single model. From the development of the CODA model, several hypotheses are proposed and applied to musical contexts. These hypotheses address theoretical issues such as acknowledging individual and contextual differences in emotional intensity and valence, as well as differentiating between induced and perceived emotions, and utilitarian and aesthetic emotions. We conclude with a sections of recommendations for future research. Altogether, this theoretical critique and proposed model points toward a positive future direction for music-emotion science. One where researchers can take forward testable predictions about what makes music relevant and meaningful to an individual. (shrink)

In this response to Neil Manson’s latest intervention in our debate about the best consent model for biobank research we show, contra Manson that the ‘expiry problem’ that affects broad consent models because of changes over time in methods, purposes, types of data used and governance structures is a real and significant problem. We further show that our preferred implementation of meta consent as a national consent platform solves this problem and is not subject to the cost and burden (...) objections that Manson raises. (shrink)

Historians have long since rejected the dubious assertions of the conflict model, with its narratives of perennial religion versus science combat. Nonetheless, this theory persists in various academic disciplines, and it is still presented to university students as the authoritative historical account of religion–science interactions. Cases of this can be identified within modern anthropology textbooks and reference materials, which often recapitulate claims once made by John W. Draper and Andrew D. White. This article examines 21st-century introductory anthropology publications, demonstrating (...) how such works perpetuate religion–science myths and the notion that history has been replete with inevitable religion versus science warfare. In particular, this study reveals how such introductory materials propagate discord narratives associated with the Scientific Revolution and the Enlightenment. Affiliated with these anecdotes are oversimplified accounts of religious responses to heliocentrism and evolutionary theory, as well as claims that science has invariably led to the usurpation of religious belief and secularization from Galileo onwards. (shrink)

The introduction of statistical models represented by directed acyclic graphs (DAGs) has proved fruitful in the construction of expert systems, in allowing efficient updating algorithms that take advantage of conditional independence relations (Pearl, 1988, Lauritzen et al. 1993), and in inferring causal structure from conditional independence relations (Spirtes and Glymour, 1991, Spirtes, Glymour and Scheines, 1993, Pearl and Verma, 1991, Cooper, 1992). As a framework for representing the combination of causal and statistical hypotheses, DAG models have shed light on a (...) number of issues in statistics ranging from Simpson’s Paradox to experimental design (Spirtes, Glymour and Scheines, 1993). The relations of DAGs with statistical constraints, and the equivalence and distinguishability properties of DAG models, are now well understood, and their characterization and computation involves three properties connecting graphical structure and probability distributions: (i) a local directed Markov property, (ii) a global directed Markov property, (iii) and factorizations of joint densities according to the structure of a graph (Lauritizen, et al., 1990). (shrink)

Late in a career of more than sixty years, Thomas Burch, an internationally known social demographer, undertook a wide-ranging methodological critique of demography. This open access volume contains a selection of resulting papers, some previously unpublished, some published but not readily accessible [from past meetings of The International Union for the Scientific Study of Population and its research committees, or from other small conferences and seminars]. Rejecting the idea that demography is simply a branch of applied statistics, his work views (...) it as an autonomous and complete scientific discipline. When viewed from the perspective of modern philosophy of science, specifically the semantic or model-based school, demography is a balanced discipline, with a rich body of techniques and data, but also with more and better theories than generally recognized. As demonstrated in this book, some demographic techniques can also be seen as theoretical models, and some substantive/behavioral models, commonly rejected as theory because of inconsistent observations, are now seen as valuable theoretical models, for example demographic transition theory. This book shows how demography can build a strong theoretical edifice on its broad and deep empirical foundation by adoption of the model-based approach to science. But the full-fruits of this approach will require demographers to make greater use of computer modeling [both macro- and micro-simulation], in the statement and manipulation of theoretical ideas, as well as for numerical computation. This book is open access under a CC BY license. (shrink)

ABSTRACT Economists not only failed to anticipate the financial crisis; they may have contributed to it—with risk and derivatives models that, through spurious precision and untested theoretical assumptions, encouraged policy makers and market participants to see more stability and risk sharing than was actually present. Moreover, once the crisis occurred, it was met with incomprehension by most economists because of models that, on the one hand, downplay the possibility that economic actors may exhibit highly interactive behavior; and, on the other, (...) assume that any homogeneity will involve economic actors sharing the economist’s own putatively correct model of the economy, so that error can stem only from an exogenous shock. The financial crisis presents both an ethical and an intellectual challenge to economics, and an opportunity to reform its study by grounding it more solidly in reality. (shrink)

After a wave of breakthroughs in image‐based medical diagnostics and risk prediction models, machine learning (ML) has turned into a normal science. However, prominent researchers are claiming that another paradigm shift in medical ML is imminent—due to most recent staggering successes of large language models—from single‐purpose applications toward generalist models, driven by natural language. This article investigates the implications of this paradigm shift for the ethical debate. Focusing on issues like trust, transparency, threats of patient autonomy, responsibility issues in the (...) collaboration of clinicians and ML models, fairness, and privacy, it will be argued that the main problems will be continuous with the current debate. However, due to functioning of large language models, the complexity of all these problems increases. In addition, the article discusses some profound challenges for the clinical evaluation of large language models and threats to the reproducibility and replicability of studies about large language models in medicine due to corporate interests. (shrink)

§1. Introduction. With Hrushovski's proof of the function field Mordell-Lang conjecture [16] the relevance of geometric stability theory to diophantine geometry first came to light. A gulf between logicians and number theorists allowed for contradictory reactions. It has been asserted that Hrushovski's proof was simply an algebraic argument masked in the language of model theory. Another camp held that this theorem was merely a clever one-off. Still others regarded the argument as magical and asked whether such sorcery could unlock (...) the secrets of a wide coterie of number theoretic problems.In the intervening years each of these prejudices has been revealed as false though such attitudes are still common. The methods pioneered in [16] have been extended and applied to a number of other problems. At their best, these methods have been integrated into the general methods for solving diophantine problems. Moreover, the newer work suggests limits to the application of model theory to diophantine geometry. For example, all such known applications are connected with commutative algebraic groups. This need not be an intrinsic restriction, but its removal requires serious advances in the model theory of fields. (shrink)

This article discusses the basic arguments and important achievements of Jane Bennett’s vital materialism, as well as some problems and limitations of this theoretical perspective. It first analyzes the ontological underpinnings of Bennett’s materialist account and presents two examples she uses to illustrate the notion of a ‘force of things’. The paper then addresses central conceptual and analytic problems of Bennett’s account. The notion of an all-encompassing ‘vitality of matter’ is insufficient to explain the relationality of matter; it is also (...) empirically limited and provides only a selective account of agency. These shortcomings and limitations affect the political perspectives of Bennett’s version of vital materialism. I conclude that there is a tendency in her work to displace political considerations by invoking new ethical responsibilities and sensibilities. Being attentive to the vitality of things translates into a systematic blindness concerning the inequalities, asymmetries and hierarchies enacted in vital materializations. (shrink)

" In Being No One, Metzinger, a German philosopher, draws strongly on neuroscientific research to present a representationalist and functional analysis of...

Condorcet's jury theorem shows that when the members of a group have noisy but independent information about what is best for the group as a whole, majority decisions tend to outperform dictatorial ones. When voting is supplemented by communication, however, the resulting interdependencies between decision makers can strengthen or undermine this effect: they can facilitate information pooling, but also amplify errors. We consider an intriguing non-human case of independent information pooling combined with communication: the case of nest-site choice by honeybee (...) (Apis mellifera) swarms. It is empirically well documented that when there are different nest sites that vary in quality, the bees usually choose the best one. We develop a new agent-based model of the bees' decision process and show that its remarkable reliability stems from a particular interplay of independence and interdependence between the bees. (shrink)

We consider the results of adding to a basic modal system T0the axioms G1.CLpp;Pn.CLnpLn+1p; Bn.CpLnMp, where n ≧ 11, in all combinations. The method of Meredith's [7] will be extended to get models of these systems in lower predicate calculus (LPC) with a constant binary relation,U. Most of the results were already obtained in [1]–[6], though systems as in (i) and (ii) below were not investigated, except that S40in (ii) was mentioned in [1]. However some repetition may be excused in (...) view of the simplicity with which the results are obtained by the present method. (shrink)

Flexibility is one of the hallmarks of human problem‐solving. In everyday life, people adapt to changes in common tasks with little to no additional training. Much of the existing work on flexibility in human problem‐solving has focused on how people adapt to tasks in new domains by drawing on solutions from previously learned domains. In real‐world tasks, however, humans must generalize across a wide range of within‐domain variation. In this work we argue that representational abstraction plays an important role in (...) such within‐domain generalization. We then explore the nature of this representational abstraction in realistically complex tasks like video games by demonstrating how the same model‐based planning framework produces distinct generalization behaviors under different classes of task representation. Finally, we compare the behavior of agents with these task representations to humans in a series of novel grid‐based video game tasks. Our results provide evidence for the claim that within‐domain flexibility in humans derives from task representations composed of propositional rules written in terms of objects and relational categories. (shrink)

This special issue on Formal Models of Awareness contains five papers that concentrate on different approaches to the notion of awareness. They include syntactic and semantic approaches to modelling awareness and an alternative view from the multi-agent systems perspective where awareness is identified as the ability to perceive and understand actions of other agents.Velázquez-Quesada studies a logic of plausibility acknowledgement models used to interpret the notions of implicit and explicit beliefs. The models use the notion of a formula being acknowledged (...) as true that is similar to syntactic awareness in that the set of formulas acknowledged as true by an agent is not assumed to be closed under logical consequence. However it has a different meaning . A dynamic epistemic logic over such models is cons .. (shrink)

Since the days of classical Montague Grammar, formal semantics is frequently characterised as intensional, type-logical and model-theoretic. This paper takes a closer look of some less obvious changes these three key concepts have undergone since the appearance of English as a Formal Language. While intensions used to be crucial for resolving substitution puzzles, they are now giving way to more general constructions of index-dependant denotations. Types, on the other hand, were promoted from handy taxonomic devices to driving forces in (...) meaning composition. Finally, the rôle of models was overestimated in the early days of formal semantics, but appears to have lost its importance. (shrink)

We here make preliminary investigations into the model theory of DeMorgan logics. We demonstrate that Łoś's Theorem holds with respect to these logics and make some remarks about standard model-theoretic properties in such contexts. More concretely, as a case study we examine the fate of Cantor's Theorem that the classical theory of dense linear orderings without endpoints is $\aleph_{0}$-categorical, and we show that the taking of ultraproducts commutes with respect to previously established methods of constructing nonclassical structures, namely, (...) Priest's Collapsing Lemma and Dunn's Theorem in 3-Valued Logic. (shrink)

Justification logics are epistemic logics that explicitly include justifications for the agents' knowledge. We develop a multi-agent justification logic with evidence terms for individual agents as well as for common knowledge. We define a Kripke-style semantics that is similar to Fitting's semantics for the Logic of Proofs LP. We show the soundness, completeness, and finite model property of our multi-agent justification logic with respect to this Kripke-style semantics. We demonstrate that our logic is a conservative extension of Yavorskaya's minimal (...) bimodal explicit evidence logic, which is a two-agent version of LP. We discuss the relationship of our logic to the multi-agent modal logic S4 with common knowledge. Finally, we give a brief analysis of the coordinated attack problem in the newly developed language of our logic. (shrink)

It is often assumed that similar domain-specific behavioural impairments found in cases of adult brain damage and developmental disorders correspond to similar underlying causes, and can serve as convergent evidence for the modular structure of the normal adult cognitive system. We argue that this correspondence is contingent on an unsupported assumption that atypical development can produce selective deficits while the rest of the system develops normally (Residual Normality), and that this assumption tends to bias data collection in the field. Based (...) on a review of connectionist models of acquired and developmental disorders in the domains of reading and past tense, as well as on new simulations, we explore the computational viability of Residual Normality and the potential role of development in producing behavioural deficits. Simulations demonstrate that damage to a developmental model can produce very different effects depending on whether it occurs prior to or following the training process. Because developmental disorders typically involve damage prior to learning, we conclude that the developmental process is a key component of the explanation of endstate impairments in such disorders. Further simulations demonstrate that in simple connectionist learning systems, the assumption of Residual Normality is undermined by processes of compensation or alteration elsewhere in the system. We outline the precise computational conditions required for Residual Normality to hold in development, and suggest that in many cases it is an unlikely hypothesis. We conclude that in developmental disorders, inferences from behavioural deficits to underlying structure crucially depend on developmental conditions, and that the process of ontogenetic development cannot be ignored in constructing models of developmental disorders. Key Words: Acquired and developmental disorders; connectionist models; modularity; past tense; reading. (shrink)