The way students perceive a learning climate (e.g. controlling or stimulating) is significantly influenced by feedback and assessment. However, at present much is unclear about the relation between feedback and motivational state. More specifically, the interplay with student characteristics is unclear. Since there is a strong increase of group work, the central research question is what are the effects of positive, neutral or negative feedback presented to collaborating teams of students, on students? intrinsic motivation, performance and on group processes? One (...) hundred thirty?eight higher education students participated in this study. There were no significant differences in performance across conditions. Multi?level analysis enabled a detailed comparison between groups and individual members of groups. Amongst others, it was found that feelings of competence facilitate the effect of positive feedback at the group level, which suggests that positive feedback boosts interest especially in groups of highly competent students. (shrink)

For some of us, the defeasibility theory of knowledge remains the most plausible approach to the Gettier Problem. Epistemological fashion and faded memories notwithstanding, persuasive objections to the theory are very hard to find. The most impressive of those objections to the theory that have hitherto gone unanswered are examined and rejected here. These are objections put forward by Richard Feldman, Richard Foley, and John Turri. While these are all interesting, the objection recently put forward by Turri is, we think, (...) by far, the most serious threat to the theory that we have seen in a long time. A successful reply to it requires a surprising amount of care, as it turns out. If tenable, Turri's objection deals a devastating blow to the theory developed by Roderick Chisholm, Keith Lehrer, Peter Klein, Marshall Swain, Risto Hilpinen, John Pollock, and Paul Moser, among others. Under scrutiny, however, the threat proves illusory. It results from inattention to a crucial, but relatively subtle, aspect of.. (shrink)

In this paper we study in details a system of two weakly coupled harmonic oscillators from the point of view of Bohm's interpretation of quantum mechanics. This system may be viewed as a simple model for the interaction between a photon and a photodetector. We obtain exact solutions for the general case. We then compute approximate solutions for the case where one oscillator is initially in its first excited state (a single photon) reaching the other oscillator in its ground state (...) (the photodetector). The approximate solutions represent the state of both oscillators after the interaction, which is not an eigenstate of the individual hamiltonians for each oscillator, and therefore the energies for each oscillator do not exist in the Copenhagen interpretation of Quantum Mechanics. We use the approximate solutions that we obtained to compute Bohmian trajectories and to study the energy transfer between the oscillators. We conclude that, even using the Bohmian view, the energy of each individual oscillator is not well defined, as the nonlocal quantum potential is not negligible even after the coupling is turned off. (shrink)

In this paper we study in details a system of two weakly coupled harmonic oscillators from the point of view of Bohm’s interpretation of quantum mechanics. This system may be viewed as a simple model for the interaction between a photon and a photodetector. We obtain exact solutions for the general case. We then compute approximate solutions for the case where one oscillator is initially in its first excited state (a single photon) reaching the other oscillator in its ground state (...) (the photodetector). The approximate solutions represent the state of both oscillators after the interaction, which is not an eigenstate of the individual hamiltonians for each oscillator, and therefore the energies for each oscillator do not exist in the Copenhagen interpretation of Quantum Mechanics. We use the approximate solutions that we obtained to compute Bohmian trajectories and to study the energy transfer between the oscillators. We conclude that, even using the Bohmian view, the energy of each individual oscillator is not well defined, as the nonlocal quantum potential is not negligible even after the coupling is turned off. (shrink)

The application of Gödel’s theorem to the problem of minds and machines is difficult. Paul Benacerraf makes the entirely valid ‘Duhemian’ point that the argument is not, and cannot be, a purely mathematical one, but needs some philosophical premisses to be able to yield any philosophical conclusions. Moreover, the philosophical premisses are of very different kinds. Some are concerned with what is essential to being a machine—these are typically intricate, but definite, easily formalised by the mathematician, but unintelligible to the (...) layman: others attempt to capture what is essential to being a mind, a person or a self—these are typically intuitive, but vague; resistant to exact definition by the logician, but, none the less, widely used and well understood. Gödel’s theorem itself, like many other truths, can be taken either way: it can be taken as a formal proof sequence yielding certain syntactical results about a certain class of formal systems, but it can also be taken as giving us a certain type or style of argument, which we can understand, and, once having got the hang of it, adapt and apply in innumerable different circumstances. In my dispute with the mechanist, I take Gödel’s argument both ways: I first take it as an argument which the mechanist, even according to his own mechanist principles, must accept as scoring some point against his favourite machine; and then I hope that the mechanist, as a man, will see that he can do better and that this sort of argument will always apply against any form of mechanism he espouses. (shrink)

The application of Gödel’s theorem to the problem of minds and machines is difficult. Paul Benacerraf makes the entirely valid ‘Duhemian’ point that the argument is not, and cannot be, a purely mathematical one, but needs some philosophical premisses to be able to yield any philosophical conclusions. Moreover, the philosophical premisses are of very different kinds. Some are concerned with what is essential to being a machine—these are typically intricate, but definite, easily formalised by the mathematician, but unintelligible to the (...) layman: others attempt to capture what is essential to being a mind, a person or a self—these are typically intuitive, but vague; resistant to exact definition by the logician, but, none the less, widely used and well understood. Gödel’s theorem itself, like many other truths, can be taken either way: it can be taken as a formal proof sequence yielding certain syntactical results about a certain class of formal systems, but it can also be taken as giving us a certain type or style of argument, which we can understand, and, once having got the hang of it, adapt and apply in innumerable different circumstances. In my dispute with the mechanist, I take Gödel’s argument both ways: I first take it as an argument which the mechanist, even according to his own mechanist principles, must accept as scoring some point against his favourite machine; and then I hope that the mechanist, as a man, will see that he can do better and that this sort of argument will always apply against any form of mechanism he espouses. (shrink)

We propose a new approach for tracing value change. Value change may lead to a mismatch between current value priorities in society and the values for which technologies were designed in the past, such as energy technologies based on fossil fuels, which were developed when sustainability was not considered a very important value. Better anticipating value change is essential to avoid a lack of social acceptance and moral acceptability of technologies. While value change can be studied historically and qualitatively, we (...) propose a more quantitative approach that uses large text corpora. It uses probabilistic topic models, which allow us to trace values that are latent. We demonstrate the approach for five types of value change in technology. Our approach is useful for testing hypotheses about value change, such as verifying whether value change has occurred and identifying patterns of value change. The approach can be used to trace value change for various technologies and text corpora, including scientific articles, newspaper articles, and policy documents. (shrink)

O objetivo deste ensaio é examinar a proposta de Sandy Goldberg, segundo a qual há divisão de trabalho epistêmico em certos processos de aquisição de conhecimento – ao menos em se tratando de conhecimento testemunhal. Goldberg propõe mostrar a veracidade desta alegação salientando a nossa dependência epistêmica em relação a outros indivíduos, ou mesmo comunidades inteiras. Nós, então, vamos propor o tratamento de um famoso caso tipo-Gettier que, segundo Gilbert Harman, revelaria algumas dimensões sociais do conhecimento. Por fim, nós esperamos (...) tirar algumas lições da explicação oferecida por Goldberg, dentre as quais a mais importante a ser tomada é que, havendo tal divisão de trabalho epistêmico em processos de aquisição de conhecimento, muitas vezes, não são apenas as propriedades epistêmicas do sujeito que determinam a sua posse de conhecimento ou ignorância, de modo que o conhecimento é mais social do que individual em se tratando de uma ampla gama de casos. (shrink)

An experimental apparatus based on neutron interferometry is is presented which can in principle decide the question whether the empty waves of de Broglie really exist or not.

O objetivo deste ensaio é examinar a recente crítica de Maria Lasonen-Aarnio à solução anulabilista do paradoxo do dogmatismo. Tal paradoxo consiste no argumento de que certos princípios epistêmicos autorizam qualquer sujeito cognoscente a desconsiderar contraevidências para o que ele sabe. Porém, esta atitude dogmática é comumente julgada como injustificada e o sujeito que a toma é comumente julgado como irracional. A solução anulabilista do paradoxo do dogmatismo foi posta em circulação por Gilbert Harman e sugere que o problema é (...) resolvido assim que se abandona a suposição de que o conhecimento não pode ser derrotado por contraevidências. Lasonen-Aarnio acredita que tal solução é insatisfatória porque ainda haveria, em certas circunstâncias, justificação para ser dogmático mesmo admitindo e sofrendo derrota epistêmica. Desse modo, a solução anulabilista deixa ainda alguma medida de dogmatismo autorizada para o sujeito. Iniciaremos com uma introdução ao problema, explicando em que consiste o paradoxo do dogmatismo e expondo as diferentes versões nas quais foi apresentado. Em seguida, vamos nos voltar para uma versão do argumento pró-dogmatismo. Consideraremos, então, a solução anulabilista proposta por Harman e a crítica de Lasonen-Aarnio. Por fim, apresentaremos três objeções à eficácia da crítica de Lasonen-Aarnio. (shrink)

In the early 1960s of the 20th century de Broglie was able to explain the cosmological observable red shift, without ad hoc assumptions. Starting from basic quantum considerations he developed his tired light model for the photon. This model explains in a single and beautiful causal way the cosmological redshift without need of assuming the Big Bang and consequently a beginning for the universe. Evidence coming from Earth sciences seems also to confirm these ideas and furthermore concrete proposal of laboratorial (...) scale experiments that can test the model are reviewed. (shrink)