Mismatch brain responses to unpredicted rare stimuli are suggested to be a neural indicator of prediction error, but this has rarely been studied in the somatosensory modality. Here, we investigated how the brain responds to unpredictable and predictable rare events. Magnetoencephalography responses were measured in adults frequently presented with somatosensory stimuli that were occasionally replaced by two consecutively presented rare stimuli [unpredictable rare stimulus and predictable rare stimulus ; p = 0.1 for each]. The FRE and PR were electrical stimulations (...) administered to either the little finger or the forefinger in a counterbalanced manner between the two conditions. The UR was a simultaneous electrical stimulation to both the forefinger and the little finger. The grand-averaged responses were characterized by two main components: one at 30–100 ms and the other at 130–230 ms latency. Source-level analysis was conducted for the primary somatosensory cortex and the secondary somatosensory cortex. The M55 responses were larger for the UR and PR than for the FRE in both the SI and the SII areas and were larger for the UR than for the PR. For M150, both investigated areas showed increased activity for the UR and the PR compared to the FRE. Interestingly, although the UR was larger in stimulus energy and had a larger prediction error potential than the PR, the M150 responses to these two rare stimuli did not differ in source strength in either the SI or the SII area. The results suggest that M55, but not M150, can possibly be associated with prediction error signals. These findings highlight the need for disentangling prediction error and rareness-related effects in future studies investigating prediction error signals. (shrink)

Stationary spacetimes containing a black hole have several properties akin to those of atoms. For instance, such spacetimes have only three classical degrees of freedom, or observables, which may be taken to be the mass, the angular momentum, and the electric charge of the hole. There are several arguments supporting a proposal originally made by Bekenstein that quantization of these classical degrees of freedom gives an equal spacing for the horizon area spectrum of black holes. We review some of these (...) arguments and introduce a specific Hamiltonian quantum theory of black holes. Our Hamiltonian quantum theory gives, among other things, a discrete spectrum for the classical observables, and it produces an area spectrum which is closely related to Bekenstein's proposal. We also present a foamlike model of horizons of spacetime. In our model spacetime horizon consists of microscopic Schwarzschild black holes. Applying our Hamiltonian approach to this model we find that the entropy of any horizon is one quarter of its area. (shrink)

Deciduous trees remobilize the nitrogen in senescing leaves during the process of autumn colouration, which in many species is associated with increased concentrations of anthocyanins. Archetti1 and Hamilton and Brown2 observed that autumn colouration is stronger in tree species facing a high diversity of specialist aphids. They proposed a coevolution theory that the bright colours in autumn might provide an honest signal of defence commitment, thus deterring migrant aphids from settling on the leaves. So far, there have been very few (...) experimental results to support the hypothesis, and tree commitment to phenolics‐based defences has not shown direct protection against aphids. Predators and parasitoids have been found to be the major controllers of arboreal aphids. Indirect defences involve the emission of attractive volatile compounds that enhance the effectiveness of carnivorous enemies. The indirect defence hypothesis is presented to explain low aphid diversity on tree species that are green during autumn. The hypothesis suggests that green foliage can continue to produce herbivore‐inducible plant volatiles and maintain volatile‐based indirect plant defences against aphids until leaf abscission. BioEssays 30:889–896, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

Fundamental assumptions behind qualitative modelling are critically considered and some inherent problems in that modelling approach are outlined. The problems outlined are due to the assumption that a sufficient set of symbols representing the fundamental features of the physical world exists. That assumption causes serious problems when modelling continuous systems. An alternative for intelligent system building for cases not suitable for qualitative modelling is proposed. The proposed alternative combines neural networks and quantitative modelling.

Climate change and decarbonization raise complex justice questions that researchers and policymakers must address. The distributions of greenhouse gas emissions rights and mitigation efforts have dominated justice discourses within scenario research, an integrative element of the IPCC. However, the space of justice considerations is much larger. At present, there is no consistent approach to comprehensively incorporate and examine justice considerations. Here we propose a conceptual framework grounded in philosophical theory for this purpose. We apply this framework to climate mitigation scenarios (...) literature as proof of concept, enabling a more holistic and multidimensional investigation of justice. We identify areas of future research, including new metrics of service provisioning essential for human well-being. [Can be freely read by clicking the ReadCube link below.]. (shrink)

Contemporary semantic theories can be classified along two dimensions: (i) the way and time-course in which contextual factors influence sentence truth-conditions; and (ii) whether and to what extent comprehension involves sensory, motor and emotional processes. In order to explore this theoretical space, our ERP study investigates the time-course of the interaction between the lexically specified telic component of a noun (the function of the object to which the noun refers to, e.g., a funnel is generally used to pour liquids into (...) containers) and an ad-hoc affordance contextually induced by the situation described in the discourse. We found that, if preceded by a neutral discourse context, a verb incongruent with the noun’s telic component as in “She uses the funnel to hang her coat” elicited an enhanced N400 compared to a congruent verb as in “She uses the funnel to pour water into a container”. However, if the situation introduced in the preceding discourse induced a new function for the object as an ad-hoc affordance (e.g., the funnel is glued to the wall and the agent wants to hang the coat), we observed a crossing-over regarding the direction of the N400 effect: comparing the ad-hoc affordance-inducing context with the neutral context, the N400 for the incongruent verb was significantly reduced, whereas the N400 for the congruent verb was significantly enhanced. We explain these results as a consequence of the incorporation of the contextually triggered ad-hoc affordance into the meaning of the noun. Combining these results with an analysis of semantic similarity values between test sentences and contexts, we argue that one possibility is that the incorporation of an ad-hoc affordance may be explained on the basis of the mental simulation of concurrent motor information. (shrink)

We study the computational complexity of the model checking problem for quantifier-free dependence logic ${(\mathcal{D})}$ formulas. We characterize three thresholds in the complexity: logarithmic space (LOGSPACE), non-deterministic logarithmic space (NL) and non-deterministic polynomial time (NP).

The book deals with the reception and critique of symbolic logic among German-speaking philosophers at the turn of the 20th century. The first part discusses the period from the late 1870s up to the end of the 19th century. The main issue is the arrival of the Boolean algebra of logic in Germany and Austria. It examines also the reasons why Gottlob Frege was so unsuccessful in his attempts to draw the attention of philosophers to his logicist programme. The second (...) part deals with the first two decades of the 20th century. Its main topic of inquiry is the reception of Bertrand Russell's and Louis Couturat's ideas in the German-speaking world. In particular, it concentrates on the relationship between Russell and neo-Kantians. (shrink)

Comment devient-on philosophe? Par quel sursaut un Aristoclès se fait-il Platon, jusqu'à s'imposer dans la liste des " auteurs philo " Il faut enquêter, non pas sur la vie privée, mais sur la vie intime : rumination intellectuelle, ton sur lequel on parle, motivations amoureuses... Ce qui fait un philosophe, c'est un immense travail sur soi, et la rencontre d'autres philosophes, vivants, de leurs problématiques. Mémoire sémantique + obsession métaphysique, voilà le code génétique du philosophe. Il débute par un attentat (...) religieux, puisqu'il commence sa carrière en niant tel ou tel sacré. Bien sûr, il vaut mieux être mâle, communiquer par les livres adopter la langue dominante, écrire quand on est célibataire. Comment gagner sa vie? Pas forcément en étant enseignant, comme c'est le cas aujourd'hui. Le profil du philosophe nous le révèle orphelin, vivant à l'étranger, souvent laid, jamais fou, et serial thinker, prêt à changer de philosophie pourvu qu'il reste, lui, à menacer le monde donnera ou donnera pas du sens à notre vie? Le philosophe est l'être inquiet qui pense inquiéter l'Être par deux trois mots bien aiguisés. (shrink)

One of Hume's most well-known works and a masterpiece of philosophy, A Treatise of Human Nature is indubitably worth taking the time to read.

Introduction: Conversion and the practice of transformation -- The philosophical structure of Jonathan Edwards's religious affections -- Habit, habit change, and conversion in C.S. Peirce -- Reconstructing faith : religious overcoming in Dewey's pragmatism -- Transforming obligation in William James -- Dwelling in absence: the reflective origin of conversion -- Creative transformation : the work of conversion -- The evasion of conversion in recent American philosophy.

The philosophy of Epictetus, a freed slave in the Roman Empire, has been profoundly influential on Western thought: it offers not only stimulating ideas but practical guidance in living one's life. A. A. Long, a leading scholar of later ancient philosophy, gives the definitive presentation of the thought of Epictetus for a broad readership. Long's fresh and vivid translations of a selection of the best of Epictetus' discourses show that his ideas are as valuable and striking today as they were (...) amost two thousand years ago. This is a book for anyone interested in what we can learn from ancient philosophy about how to live our lives. (shrink)

La filosofía de la historia se ha debatido durante siglos en una estéril lucha entre idealistas y materialistas. El libro de Ignacio Ellacuría es un intento de superar esa dicotomía clásica. Tomando como punto de partida algunos conceptos fundamentales de la filosofía de Zubiri, Ellacuría cree posible asumir y a la vez criticar ambos extremos, desde una actitud más realista. De ahí el título del libro. Es importante destacar que la historia, para Ignacio Ellacuría, es el lugar de realización de (...) la ética. La historia no está hecha, se construye, es un proceso de creación de posibilidades humanas, y, en tanto que tal, una labor ética. La tesis de Zubiri de que el hombre tiene que hacerse cargo de la realidad, en Ellacuría se transforma en esta otra: el ser humano está obligado a encargarse de la realidad, y a cargar con ella. Este es el imperativo ético. Imperativo que, por otra parte, no sólo le obliga individualmente al hombre, en el reducto de la propia conciencia, al modo del idealismo, ni tampoco sólo en tanto que miembro de una clase social, como en el marxismo, sino como sujeto a la vez individual y específico, como miembro a la vez solitario y solidario de la especie humana. La obra póstuma de Ignacio Ellacuría constituye sin duda su más ingente trabajo intelectual en el campo de la filosofía, y representa, por su calidad y contenido, una pieza clave para comprender no solamente su producción estrictamente filosófica, sino también su pensamiento teológico y socio-político. (shrink)

The purpose of this book is to trace the main developments in Greek philosophy during the period which runs from the death of Alexander the Great in 323 B.c. to the end of the Roman Republic. These three centuries, known to us as the Hellenistic Age, witnessed a vast expansion of Greek civilization eastwards, following Alexander's conquests; and later, Greek civilization penetrated deeply into the western Mediterranean world assisted by the political conquerors of Greece, the Romans. But philosophy throughout this (...) time remained a predominantly Greek activity. The most influential thinkers in the Hellenistic world were Stoics, Epicureans and Sceptics. This book gives a concise critical analysis of their ideas and their methods of thought. The last book in English to cover this ground was written sixty years ago. In the interval the subject has moved on, quite rapidly since the last war, but most of the best work is highly specialized. There is a clear need for a general appraisal of Hellenistic philosophy which can provide those who are not specialists with an up-to-date account of the subject. Hellenistic philosophy is often regarded as a dull product of second-rate thinkers who are unable to stand comparison with Plato and Aristotle. This book will help to remove such misconceptions and arouse wider interest in a field which is fascinating both historically and conceptually. (shrink)

We present the opinion of some authors who believe there is no force between a stationary charge and a stationary resistive wire carrying a constant current. We show that this force is different from zero and present its main components: the force due to the charges induced in the wire by the test charge and a force proportional to the current in the resistive wire. We also discuss briefly a component of the force proportional to the square of the current (...) which should exist according to some models and another component due to the acceleration of the conduction electrons in a curved wire carrying a dc current (centripetal acceleration). Finally, we analyze experiments showing the existence of the electric field proportional to the current in resistive wires. (shrink)