A well known theorem proved by J. Paris and H. Friedman states that BΣn +1 is a Πn +2-conservative extension of IΣn . In this paper, as a continuation of our previous work on collection schemes for Δn +1-formulas , we study a general version of this theorem and characterize theories T such that T + BΣn +1 is a Πn +2-conservative extension of T . We prove that this conservativeness property is equivalent to a model-theoretic property relating Πn-envelopes and (...) Πn-indicators for T . The analysis of Σn +1-collection we develop here is also applied to Σn +1-induction using Parsons' conservativeness theorem instead of Friedman-Paris' theorem.As a corollary, our work provides new model-theoretic proofs of two theorems of R. Kaye, J. Paris and C. Dimitracopoulos : BΣn +1 and IΣn +1 are Σn +3-conservative extensions of their parameter free versions, BΣ–n +1 and IΣ–n +1. (shrink)

By a theorem of R. Kaye, J. Paris and C. Dimitracopoulos, the class of the Πn+1-sentences true in the standard model is the only consistent Πn+1-theory which extends the scheme of induction for parameter free Πn+1-formulas. Motivated by this result, we present a systematic study of extensions of bounded quantifier complexity of fragments of first-order Peano Arithmetic. Here, we improve that result and show that this property describes a general phenomenon valid for parameter free schemes. As a consequence, we obtain (...) results on the quantifier complexity, finite axiomatizability and relative strength of schemes for Δn+1-formulas. (shrink)

The formalization of abductive reasoning has received increasing attention from logicians. However, few work is found beyond abduction in propositional logic, given that in a first order formalism, the undecidability problem naturally appears, and therefore an abductive problem cannot even be appropriately formulated. Still, many applications in artificial intelligence allow finite domains to work with, and this gives an opportunity to apply abduction in first order logic with restricted domains. In this paper, we present an approach to abductive reasoning in (...) C-structures, first order structures with a finite domain in which each of its elements has a corresponding constant representing its interpretation. By using semantic tableaux with bounded depth, that is, C-tableaux (a modification of N-tableaux, introduced by the authors in previous papers) and δ-resolution calculus, we build an effective procedure for the searching of minimal abductive solutions within the proposed semantics. (shrink)

Ce texte a déjà paru dans la Revue du MAUSS, 2011/2, n° 38, p. 339-348. Nous remercions Benjamin Fernandez et Alain Caillé de nous avoir autorisé à le reproduire ici. « Ce que nous vendons à Coca-cola, c'est du temps de cerveau disponible. » Patrick LELAY, ancien président de la chaîne privée française TF1 (2004). La pensée moderne, héritière des Lumières, avait accouché de la figure du sujet libre : une conscience de soi, substance stable et indivisible (Descartes), actrice (...) du langage et d'un (...) - 1. Comment penser le pouvoir dans le monde contemporain ? – Nouvel article. (shrink)

The capacity to be creative, to produce new concepts, ideas, inventions, objects or art, is perhaps the most important attribute of the human brain. We know very little, however, about the nature of creativity or its neural basis. Some important questions include how should we define creativity? How is it related (or unrelated) to high intelligence? What psychological processes or environmental circumstance cause creative insights to occur? How is it related to conscious and unconscious processes? What is happening at the (...) neural level during moments of creativity? How is it related to health or illness, and especially mental illness? This paper will review introspective accounts from highly creative individuals. These accounts suggest that unconscious processes play an important role in achieving creative insights. Neuroimaging studies of the brain during "REST" (random episodic silent thought, also referred to as the default state) suggest that the association cortices are the primary areas that are active during this state and that the brain is spontaneously reorganising and acting as a self-organising system. Neuroimaging studies also suggest that highly creative individuals have more intense activity in association cortices when performing tasks that challenge them to "make associations." Studies of creative individuals also indicate that they have a higher rate of mental illness than a noncreative comparison group, as well as a higher rate of both creativity and mental illness in their first-degree relatives. This raises interesting questions about the relationship between the nature of the unconscious, the unconscious and the predisposition to both creativity and mental illness. (shrink)

Interactive narratives are inextricable from the way that we understand our encounters with digital technology. This is based upon the way that these encounters are processually formed into a narrative of episodic events, arranged and re-arranged by various levels of agency. After describing past research conducted at the iCinema Research Centre at the University of New South Wales, this paper sets out a framework within which to build a relational theory of interactive narrative formation, outlining future research in the area.

The traditional verbal/nonverbal dichotomy is inadequate for completely describing cerebral lateralization. Musical functions are not necessarily mediated by the right hemisphere; evidence for a specialist left-hemisphere mechanism dedicated to the encoded speech signal is weakening, and the right hemisphere possesses considerable comprehensional powers. Right-hemisphere processing is often said to be characterized by holistic or gestalt apprehension, and face recognition may be mediated by this hemisphere partly because of these powers, partly because of the right hemisphere's involvement in emotional affect, and (...) possibly through the hypothesized existence of a specialist face processor or processors in the right. The latter hypothesis may, however, suffer the same fate as the one relating to a specialist encodedness processor for speech in the left. Verbal processing is largely the province of the left because of this hemisphere's possession of sequential, analytic, time-dependent mechanisms. Other distinctions are special cases of an analytic/holistic dichotomy. More fundamentally, however, the left hemisphere is characterized by its mediation of discriminations involving duration, temporal order, sequencing, and rhythm, at thesensory level, and especially at themotorlevel. Spatial aspects characterize the right, the mapping of exteroceptive body space, and the positions of fingers, limbs, and perhaps articulators, with respect to actual and target positions. Thus there is a continuum of function between the hemispheres, rather than a rigid dichotomy, the differences being quantitative rather than qualitative, of degree rather than of kind. (shrink)

The paper analyzes dewey's two different philosophical accounts of intelligence, one as a method of adjustment within given situations, and the other as creative of new ends and means for the realization of those ends. it also points out that these two accounts of intelligence are not mutually exclusive; and we have in their combination a parallel with scientific method, in which resolution of a specific problem requires imaginative theorizing. it is also shown that dewey's concept of 'intelligence' requires the (...) formation of certain intellectual and moral dispositions, and that reflection can become enlightened striving only when it is sustained and guided by those dispositions. (shrink)

In his thesis Para uma Teoria Geral dos Homomorfismos (1944), the Portuguese mathematician José Sebastião e Silva constructed an abstract or generalized Galois theory, that is intimately linked to F. Klein’s Erlangen Program and that foreshadows some notions and results of today’s model theory; an analogous theory was independently worked out by M. Krasner in 1938. In this paper, we present a version of the theory making use of tools which were not at Silva’s disposal. At the same time, we (...) tried to keep in mind, so much as possible, the gist of his standpoint. (shrink)

The prospect of dealing with a rapidly and inexorably bleeding patient fills most medical practitioners with alarm. When that patient is a Jehovah's Witness, the knowledge that a blood transfusion is likely to be refused turns that alarm into a state of acute anxiety and conflict. This state is further heightened when the patient is young and otherwise healthy--a situation found particularly in obstetric practice with the occurrence of ante- and post-partum haemorrhage, and ectopic pregnancy. In the last 25 years (...) in England, Wales, Scotland and Northern Ireland, there has been one maternal death in which the refusal to accept a blood transfusion has been considered to be an avoidable factor. In this article I have attempted to identify the magnitude of the problem in obstetric practice and have sought to clarify the moral and legal aspects. (shrink)

A short review is given of the Nuffield Council’s report on behavioural genetics. This review is used as an entry point to a discussion of the factors that influence the presentation of behavioural genetics in the media and in the popular scientific press. It is argued that our interest in formulating narrative explanations of our individual lives puts pressure on publishers and editors to present behavioural genetics in a selective, misleading, way. Some other influences on presentation are discussed and it (...) is suggested that the Nuffield report is particularly useful in so far as it lacks these distorting influences. (shrink)

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