R.I.G. Hughes presents a series of eight philosophical essays on the theoretical practices of physics. The first two essays examine these practices as they appear in physicists' treatises (e.g. Newton's Principia and Opticks ) and journal articles (by Einstein, Bohm and Pines, Aharonov and Bohm). By treating these publications as texts, Hughes casts the philosopher of science in the role of critic. This premise guides the following 6 essays which deal with various concerns of philosophy of physics such (...) as laws, disunities, models and representation, computer simulation, explanation, and the discourse of physics. (shrink)
: Quite rightly, philosophers of physics examine the theories of physics, theories like Quantum Mechanics, Quantum Field Theory, the Special and General Theories of Relativity, and Statistical Mechanics. Far fewer, however, examine how these theories are put to use; that is to say, little attention is paid to the practices of theoretical physicists. In the early 1950s David Bohm and David Pines published a sequence of four papers, collectively entitled, 'A Collective Description of Electron Interaction.' This essay uses (...) that quartet as a case study in theoretical practice. In Part One of the essay, each of the Bohm-Pines papers is summarized, and within each summary an overview is given, framing a more detailed account. In Part Two theoretical practice is broken into six elements: (a) the use of models, (b) the use of theory, (c) modes of description and narrative, (d) the use of approximations, (e) experiment and theory, (f) the varied steps employed in a deduction. The last element is the largest, drawing as it does from the earlier ones. Part Three enlarges on the concept of 'theoretical practice,' and briefly outlines the subsequent theoretical advances which rendered the practices of Bohm and Pines obsolete, if still respected. (shrink)
A general account of modeling in physics is proposed. Modeling is shown to involve three components: denotation, demonstration, and interpretation. Elements of the physical world are denoted by elements of the model; the model possesses an internal dynamic that allows us to demonstrate theoretical conclusions; these in turn need to be interpreted if we are to make predictions. The DDI account can be readily extended in ways that correspond to different aspects of scientific practice.
One problem with assessing quantum logic is that there are considerable differences between its practitioners. In particular they offer different versions of the set of sentences which the logic governs. On some accounts the sentences involved describe events, on others they are ascriptions of properties. In this paper a framework is offered within which to discuss different quantum logical interpretations of quantum theory, and then the works of Jauch, Putnam, van Fraassen and Kochen are located within it.
Dementia is an illness that raises important questions about our own attitudes to illness and aging. It also raises very important issues beyond the bounds of dementia to do with how we think of ourselves as people--fundamental questions about personal identity. Is the person with dementia the same person he or she was before? Is the individual with dementia a person at all? In a striking way, dementia seems to threaten the very existence of the self.LThis book brings together philosophers (...) and practitioners to explore the conceptual issues that arise in connection with this increasingly common illness. Drawing on a variety of philosophers such as Descartes, Lock, Hume, Wittgenstein, the authors explore the nature of personal identity in dementia. They also show how the lives and selfhood of people with dementia can be enhanced by attention to their psychological and spiritual environment. Throughout, the book conveys a strong ethical message, arguing in favor of treating people with dementia with all the dignity they deserve as human beings. The book covers a range of topics, stretching from talk of basic biology to talk of a spiritual understanding of people with dementia. Accessibly written by leading figures in psychiatry and philosophy, the book presents a unique and long overdue examination of an illness that features in so many of our lives. (shrink)
It is widely agreed that medical researchers who conduct studies in low- and middle-income countries (LMICs) are morally required to ensure that their research benefits the broader host community, not only the subjects. The justification for this moral requirement has not been adequately examined. Most attempts to justify this requirement focus on researchers' interaction with the community as a whole, not on their relationship with their subjects. This paper argues that in some cases, research must benefit the broader host community (...) for researchers to treat subjects and prospective subjects ethically. If research presents substantial net risks to subjects, researchers can ethically ask LMIC citizens to participate only if people in LMICs, normally including people in the host community, stand to benefit. (shrink)
Focusing on a discussion by Ruddich and Stassen of the ?Remarks on Frazer's Golden Bough?, this paper shows that some of the usual criticisms made by sociologists of Wittgenstein are misplaced. He does not reject causal explanations of beliefs and actions and replace them with some other form of explanation, but dismisses the idea that any explanation is called for here. His argument that the origin of the desire to explain beliefs is to be found in a misconceived parallel between (...) science and magic is explained and discussed. (shrink)
Probability kinematics is the theory of how subjective probabilities change with time, in response to certain constraints (accepted by the subject). Rules are classified by the imposed constraints for which the rules prescribe a procedure for updating one's opinion. The first is simple conditionalization (constraint: give probability 1 to proposition A), and the second Jeffrey conditionalization (constraint: give probability x i , 0 i ). It is demonstrated by a symmetry argument that these rules are the unique admissible rules for (...) those constraints, and moreover, that any probability kinematic rule must be equivalent to a (simple or Jeffrey) conditionalization preceded by a determination of the values x i to be given to the members of such a partition. Next two rival rules which can go beyond such conditionalization are described. INFOMIN (minimize relative information) and MTP (maximize transition probability). Their properties are investigated and compared. (shrink)
The pair (A, Δ ), where A is a physical quantity (an observable) and Δ a subset of the reals, may be called an 'experimental question'. The set Q of experimental questions is, in classical mechanics, a Boolean algebra, and in quantum mechanics an orthomodular lattice (and also a transitive partial Boolean algebra). The question is raised: can we specify a priori what algebraic structure Q must have in any theory whatsoever? Several proposals suggesting that Q must be a lattice (...) are discussed, and rejected in favor of the weak claim that Q must be a Boolean atlas. (shrink)
Les dépenses en médicaments augmentent plus rapidement que les ressources disponibles. Les facteurs qui jouent sur l’augmentation des dépenses en médicaments au Canada sont essentiellement associés au volume d’utilisation et à l’arrivée de nouveaux médicaments. Parmi ceux-ci, certains sont extrêmement onéreux et apportent peu de bénéfices par rapport à leur coût. Les évaluateurs sont amenés à s’interroger sur l’opportunité de les inscrire sur la liste des produits couverts par le régime public. L’un des problèmes les plus persistants pour les agences (...) d’évaluations est celui de justifier le refus de rembourser un médicament sur la base de son coût élevé. Nous croyons que le rationnement de médicaments très chers peut s’appuyer sur une justification transparente qui comprend, outre des données probantes, des principes et des valeurs éthiques. Dans cet article, nous entreprenons d’établir et d’analyser les critères et principes pharmaco-économiques et éthiques à considérer lorsqu’il s’agit de limiter équitablement l’accès à des médicaments onéreux. (shrink)
Strong evidence indicates that non-human primates possess a numerical representation system, but the inherent nature of that system is still debated. Two cognitive mechanisms have been proposed to account for non-human primate numerical performance: (1) a discrete object-file system limited to quantities 4), or span (small vs. large) numbers of food items presented simultaneously or sequentially. The prediction from the object-file hypothesis is that baboons will only accurately choose the larger quantity in small pairs, but not large or span pairs. (...) Conversely, the analog system predicts that baboons will be successful with all numbers, and that success will be dependent on numerical ratio. We found that baboons successfully discriminated all pair types at above chance levels. In addition, performance significantly correlated with the ratio between the numerical values. Although performance was better for simultaneous trials than sequential trials, evidence favoring analog numerical representation emerged from both conditions, and was present even in the first exposure to number pairs. Together, these data favor the interpretation that a single, coherent analog representation system underlies spontaneous quantitative abilities in primates. (shrink)
The curvature of a decision maker's utility function is often used to measure his risk preference. In order to comprehensively describe an individual's decision making behaviour, however, it would also seem desirable to measure the gain in utility from an increase in wealth or income before accounting for risk. If a small increase in wealth leads to a large utility gain, then it could be said that the individual's aspiration to achieve the wealth increase would be high. This aspiration, however, (...) may be more than offset by the risk involved in obtaining this extra wealth and the individual's attitude towards risk. In the following paper it is shown how the marginal utility of Marshall can be used in a measure of aspiration with this measure then combined with the usual measure of risk preference to explain the shape of any individuals utility curve. Using these measures, a general utility curve for all income or wealth classes is postulated. (shrink)
The two person exchange game is analysed using core theory, the Nash solution and the competitive equilibrium. It is shown for specific utility functions that relative to the other trader, the less wealthy trader does better under the Nash solution than he would under the competitive solution. Conversely, the trader with the lower initial utility level does better under the competitive solution than he would under the Nash solution. If traders have disparate initial endowments, it is argued that outcomes should (...) be restricted to a reduced core containing the Nash and competitive solutions as endpoints. (shrink)
Within the context of global health development approaches, surgical missions to provide care for underserved populations remain the least studied interventions with regard to their methodology. Because of the unique logistical needs of delivering operative care, surgical missions are often described solely in terms of cases performed, with a paucity of discourse on medical ethics. Within surgery, subspecialties that serve patients on a non-elective basis should, it could be argued, create mission strategies that involve a didactic approach and the propagation (...) of sustainable surgical care. The ethical considerations have yet to be described for paediatric neurosurgical outreach missions. We present here the perspectives of neurosurgeons who have participated in surgical outreach missions in Central America, South America, Eastern Europe and sub-Saharan Africa from the vantage point of both the visiting mission team and the host team that accommodates the mission efforts. (shrink)