Abraham ibn Ezra the Spaniard was one of the foremost transmitters of Arabic science to the West. His astrological and astronomical works, written in Hebrew and later translated into Latin, were considered authoritative by many medieval Jewish and Christian scholars. Some of the works he translated from Arabic are no longer extant in their original form, and on occasion his treatises provide information about earlier sources that is otherwise poorly preserved, if at all. Ibn Ezra seems to be the earliest (...) scholar to record one of the seven methods for setting up the astrological houses, and this method was subsequently used by Levi ben Gerson in southern France. Abraham ibn Ezra d'Espagne fut l'un des plus importants savants ayant contribué à la transmission de la science arabe à l'Occident. Ses ouvrages en astrologie et en astronomie, rédigés en hébreu puis traduits en latin, étaient considéréd comme faisant autorité par de nombreux savants juifs et Chrétiens. Parmi les ouvrages qu'il a traduits de l'arabe en hébreu, certains sont perdus dans leur langue originale et ses propres ouvrages renferment certaines informations concernant des sources anciennes mal ou pas du tout connues par ailleurs. Ibn Ezra semble être le premier a avoir consigne l'une des sept méthodes pour dresser les maisons astrologiques. Cette méthode avait par la suite été utilisée par Lévi ben Gershom dans le Midi de la France. (shrink)
[Correction Notice: An erratum for this article was reported in Vol 109 of Psychological Review. Due to circumstances that were beyond the control of the authors, the studies reported in "Models of Ecological Rationality: The Recognition Heuristic," by Daniel G. Goldstein and Gerd Gigerenzer overlap with studies reported in "The Recognition Heuristic: How Ignorance Makes Us Smart," by the same authors and with studies reported in "Inference From Ignorance: The Recognition Heuristic". In addition, Figure 3 in the Psychological Review (...) article was originally published in the book chapter and should have carried a note saying that it was used by permission of Oxford University Press.] One view of heuristics is that they are imperfect versions of optimal statistical procedures considered too complicated for ordinary minds to carry out. In contrast, the authors consider heuristics to be adaptive strategies that evolved in tandem with fundamental psychological mechanisms. The recognition heuristic, arguably the most frugal of all heuristics, makes inferences from patterns of missing knowledge. This heuristic exploits a fundamental adaptation of many organisms: the vast, sensitive, and reliable capacity for recognition. The authors specify the conditions under which the recognition heuristic is successful and when it leads to the counter-intuitive less-is-more effect in which less knowledge is better than more for making accurate inferences. (shrink)
Ce texte constitue le chapitre 12 du livre de J. S. Goldstein, Long Cycles : Prosperity and War in the Modern Age, New Haven, Yale University Press, 1988. L'ensemble du livre est accessible ici. - Économie et Marxisme – Nouvel article.
Leon J. Goldstein critically examines the philosophical role of concepts and concept formation in the social sciences. The book undertakes a study of concept formation and change by looking at four critical terms in anthropology , politics , and sociology.
Jürgen Goldstein gibt Antwort auf diese Fragen, indem er zunächst den von Descartes vorausgesetzten Kontingenzbegriff in seiner Genese rekonstruiert – eine Begriffsgeschichte des Terminus "contingentia" stellt noch immer ein Desiderat ...
outrageous remarks about contradictions. Perhaps the most striking remark he makes is that they are not false. This claim first appears in his early notebooks (Wittgenstein 1960, p.108). In the Tractatus, Wittgenstein argued that contradictions (like tautologies) are not statements (Sätze) and hence are not false (or true). This is a consequence of his theory that genuine statements are pictures.
Humans and animals make inferences about the world under limited time and knowledge. In contrast, many models of rational inference treat the mind as a Laplacean Demon, equipped with unlimited time, knowledge, and computational might. Following H. Simon's notion of satisficing, the authors have proposed a family of algorithms based on a simple psychological mechanism: one-reason decision making. These fast and frugal algorithms violate fundamental tenets of classical rationality: They neither look up nor integrate all information. By computer simulation, the (...) authors held a competition between the satisficing "Take The Best" algorithm and various "rational" inference procedures. The Take The Best algorithm matched or outperformed all competitors in inferential speed and accuracy. This result is an existence proof that cognitive mechanisms capable of successful performance in the real world do not need to satisfy the classical norms of rational inference. (shrink)
Bohmian mechanics and the Ghirardi-Rimini-Weber theory provide opposite resolutions of the quantum measurement problem: the former postulates additional variables (the particle positions) besides the wave function, whereas the latter implements spontaneous collapses of the wave function by a nonlinear and stochastic modification of Schrödinger's equation. Still, both theories, when understood appropriately, share the following structure: They are ultimately not about wave functions but about 'matter' moving in space, represented by either particle trajectories, fields on space-time, or a discrete set of (...) space-time points. The role of the wave function then is to govern the motion of the matter. (shrink)
That all pleasure is good and all pain bad in itself is an eternally true ethical principle. The common claim that some pleasure is not good, or some pain not bad, is mistaken. Strict particularism (ethical decisions must be made case by case; there are no sound universal normative principles) and relativism (all good and bad are relative to society) are among the ethical theories we may refute through an appeal to pleasure and pain. Daniel Dennett, Philippa Foot, R M (...) Hare, Gilbert Harman, Immanuel Kant, J. L. Mackie, and Jean-Paul Sartre are among the many philosophers addressed. (shrink)
In the last quarter of the nineteenth century, Ludwig Boltzmann explained how irreversible macroscopic laws, in particular the second law of thermodynamics, originate in the time-reversible laws of microscopic physics. Boltzmann’s analysis, the essence of which I shall review here, is basically correct. The most famous criticisms of Boltzmann’s later work on the subject have little merit. Most twentieth century innovations – such as the identiﬁcation of the state of a physical system with a probability distribution on its phase space, (...) of its thermodynamic entropy with the Gibbs entropy of , and the invocation of the notions of ergodicity and mixing for the justiﬁcation of the foundations of statistical mechanics – are thoroughly misguided. (shrink)
Bohmian mechanics and the Ghirardi–Rimini–Weber theory provide opposite resolutions of the quantum measurement problem: the former postulates additional variables besides the wave function, whereas the latter implements spontaneous collapses of the wave function by a nonlinear and stochastic modification of Schrödinger's equation. Still, both theories, when understood appropriately, share the following structure: They are ultimately not about wave functions but about ‘matter’ moving in space, represented by either particle trajectories, fields on space-time, or a discrete set of space-time points. The (...) role of the wave function then is to govern the motion of the matter. Introduction Bohmian Mechanics Ghirardi, Rimini, and Weber 3.1 GRWm 3.2 GRWf 3.3 Empirical equivalence between GRWm and GRWf Primitive Ontology 4.1 Primitive ontology and physical equivalence 4.2 Primitive ontology and symmetry 4.3 Without primitive ontology 4.4 Primitive ontology and quantum state Differences between BM and GRW 5.1 Primitive ontology and quadratic functionals 5.2 Primitive ontology and equivariance A Plethora of Theories 6.1 Particles, fields, and flashes 6.2 Schrödinger wave functions and many-worlds The Flexible Wave Function 7.1 GRWf without collapse 7.2 Bohmian mechanics with collapse 7.3 Empirical equivalence and equivariance What is a Quantum Theory without Observers&quest. (shrink)
Bohmian mechanics and the Ghirardi–Rimini–Weber theory provide opposite resolutions of the quantum measurement problem: the former postulates additional variables (the particle positions) besides the wave function, whereas the latter implements spontaneous collapses of the wave function by a nonlinear and stochastic modification of Schrödinger's equation. Still, both theories, when understood appropriately, share the following structure: They are ultimately not about wave functions but about matter moving in space, represented by either particle trajectories, fields on space-time, or a discrete set of (...) space-time points. The role of the wave function then is to govern the motion of the matter. Introduction Bohmian Mechanics Ghirardi, Rimini, and Weber 3.1 GRWm 3.2 GRWf 3.3 Empirical equivalence between GRWm and GRWf Primitive Ontology 4.1 Primitive ontology and physical equivalence 4.2 Primitive ontology and symmetry 4.3 Without primitive ontology 4.4 Primitive ontology and quantum state Differences between BM and GRW 5.1 Primitive ontology and quadratic functionals 5.2 Primitive ontology and equivariance A Plethora of Theories 6.1 Particles, fields, and flashes 6.2 Schrödinger wave functions and many-worlds The Flexible Wave Function 7.1 GRWf without collapse 7.2 Bohmian mechanics with collapse 7.3 Empirical equivalence and equivariance What is a Quantum Theory without Observers? CiteULike Connotea Del.icio.us What's this? (shrink)
In Bohmian mechanics elementary particles exist objectively, as point particles moving according to a law determined by a wavefunction. In this context, questions as to whether the particles of a certain species are real---questions such as, Do photons exist? Electrons? Or just the quarks?---have a clear meaning. We explain that, whatever the answer, there is a corresponding Bohm-type theory, and no experiment can ever decide between these theories. Another question that has a clear meaning is whether particles are intrinsically distinguishable, (...) i.e., whether particle world lines have labels indicating the species. We discuss the intriguing possibility that the answer is no, and particles are points---just points. (shrink)
Bohmian mechanics is a theory about point particles moving along trajectories. It has the property that in a world governed by Bohmian mechanics, observers see the same statistics for experimental results as predicted by quantum mechanics. Bohmian mechanics thus provides an explanation of quantum mechanics. Moreover, the Bohmian trajectories are defined in a non-conspiratorial way by a few simple laws.
Bohmian mechanics, which is also called the de Broglie-Bohm theory, the pilot-wave model, and the causal interpretation of quantum mechanics, is a version of quantum theory discovered by Louis de Broglie in 1927 and rediscovered by David Bohm in 1952. It is the simplest example of what is often called a hidden variables interpretation of quantum mechanics. In Bohmian mechanics a system of particles is described in part by its wave function, evolving, as usual, according to Schrödinger's equation. However, the (...) wave function provides only a partial description of the system. This description is completed by the specification of the actual positions of the particles. The latter evolve according to the.. (shrink)
A major disagreement between different views about the foundations of quantum mechanics concerns whether for a theory to be intelligible as a fundamental physical theory it must involve a ‘primitive ontology’ (PO), i.e. variables describing the distribution of matter in four-dimensional space–time. In this article, we illustrate the value of having a PO. We do so by focussing on the role that the PO plays for extracting predictions from a given theory and discuss valid and invalid derivations of predictions. To (...) this end, we investigate a number of examples based on toy models built from the elements of familiar interpretations of quantum theory.11 Introduction2 The GRWm and GRWf Theories2.1 The GRW process2.2 GRWm2.3 GRWf3 Predictions and Primitive Ontology3.1 Calibration functions3.2 Taking the PO seriously3.3 Examples from the literature3.4 The main theorem about operators in the GRW formalism3.5 The GRW formalism4 A Set of Examples4.1 Bohmian mechanics4.2 Bohmian trajectories and GRW collapses4.2.1 Bohm’s law and GRW’s law4.2.2 Bohm’s law and a modified GRW law4.2.3 Trajectories from the GRW wave function4.2.4 Configuration jumps and GRW law4.2.5 Another way of configuration jumps and GRW law4.3 MBM: Bohm-like trajectories from the master equation4.3.1 Empirical equivalence of MBM with GRWm and GRWf4.4 Master equation and matter density4.5 Master equation and flashes5 Conclusions. (shrink)
Schrödinger’s first proposal for the interpretation of quantum mechanics was based on a postulate relating the wave function on configuration space to charge density in physical space. Schrödinger apparently later thought that his proposal was empirically wrong. We argue here that this is not the case, at least for a very similar proposal with charge density replaced by mass density. We argue that when analyzed carefully, this theory is seen to be an empirically adequate many-worlds theory and not an empirically (...) inadequate theory describing a single world. Moreover, this formulation—Schrödinger’s first quantum theory—can be regarded as a formulation of the many-worlds view of quantum mechanics that is ontologically clearer than Everett’s. (shrink)
In this paper I argue that there is a preface paradox for intention. The preface paradox for intention shows that intentions do not obey an agglomeration norm, requiring one to intend conjunctions of whatever else one intends. But what norms do intentions obey? I will argue that intentions come in degrees. These partial intentions are governed by the norms of the probability calculus. First, I will give a dispositional theory of partial intention, on which degrees of intention are the degrees (...) to which one possesses the dispositions characteristic of full intention. I will use this dispositional theory to defend probabilism about intention. Next, I will offer a more general argument for probabilism about intention. To do so, I will generalize recent decision theoretic arguments for probabilism from the case of belief to the case of intention. (shrink)
Despite its extraordinary predictive successes, quantum mechanics has, since its inception some seventy years ago, been plagued by conceptual di culties. The basic problem, plainly put, is this: It is not at all clear what quantum mechanics is about. What, in fact, does quantum mechanics describe?
Quantum philosophy, a peculiar twentieth-century malady, is responsible for most of the conceptual muddle plaguing the foundations of quantum physics. When this philosophy is eschewed, one naturally arrives at Bohmian mechanics, which is what emerges from Schrodinger's equation for a nonrelativistic system of particles when we merely insist that 'particles' means particles. While distinctly non-Newtonian, Bohmian mechanics is a fully deterministic theory of particles in motion, a motion choreographed by the wave function. The quantum formalism emerges when measurement situations are (...) analyzed according to this theory. When the quantum formalism is regarded as arising in this way, the paradoxes and perplexities so often associated with quantum theory simply evaporate.Bohr's ... approach to atomic problems ... is really remarkable. He is completely convinced that any understanding in the usual sense of the word is impossible. Therefore the conversation is almost immediately driven into philosophical questions, and soon you no longer know whether you really take the position he is attacking, or whether you really must attack the position he is defending. (shrink)
Against Hume and Epicurus I argue that our selection of pleasure, pain and other objects as our ultimate ends is guided by reason. There are two parts to the explanation of our attraction to pleasure, our aversion to pain, and our consequent preference of pleasure to pain: 1. Pleasure presents us with reason to seek it, pain presents us reason to avoid it, and 2. Being intelligent, human beings (and to a degree, many animals) are disposed to be guided by (...) reason, and hence by what there is reason to choose, seek, and prefer, when they act. (shrink)
A syntactically correct number-specification may fail to specify any number due to underspecification. For similar reasons, although each sentence in the Yablo sequence is syntactically perfect, none yields a statement with any truth-value. As is true of all members of the Liar family, the sentences in the Yablo sequence are so constructed that the specification of their truth-conditions is vacuous; the Yablo sentences fail to yield statements. The ‘revenge’ problem is easily defused. The solution to the semantical paradoxes offered here (...) revives the mediaeval cassatio approach, one that largely disappeared due to its incomprehending rejection by influential contemporary writers such as William Shyreswood and Thomas Bradwardine. The diagnosis readily extends to the set-theoretic paradoxes. (shrink)
: We question the claim, common since Duhem, that sixteenth century astronomy, and especially the Wittenberg interpretation of Copernicus, was instrumentalistic rather than realistic. We identify a previously unrecognized Wittenberg astronomer, Edo Hildericus (Hilderich von Varel), who presents a detailed exposition of Copernicus's cosmology that is incompatible with instrumentalism. Quotations from other sixteenth century astronomers show that knowledge of the real configuration of the heavens was unattainable practically, rather than in principle. Astronomy was limited to quia demonstrations, although demonstration propter (...) quid remained the ideal. We suggest that Osiander's notorious preface to Copernicus expresses these sixteenth century commonplaces rather than twentieth century instrumentalism, and that neither `realism', nor `instrumentalism', in their modern meanings, apply to sixteenth century astronomy. (shrink)
A major disagreement between different views about the foundations of quantum mechanics concerns whether for a theory to be intelligible as a fundamental physical theory it must involve a ‘primitive ontology’ (PO), i.e. variables describing the distribution of matter in four-dimensional space–time. In this article, we illustrate the value of having a PO. We do so by focusing on the role that the PO plays for extracting predictions from a given theory and discuss valid and invalid derivations of predictions. To (...) this end, we investigate a number of examples based on toy models built from the elements of familiar interpretations of quantum theory. (shrink)
People see five kinds of views in epistemology and ontology as hinging on there being words a person can learn only by private ostensive definitions, through direct acquaintance with his own sensations: skepticism about other minds, 2. skepticism about an external world, 3. foundationalism, 4. dualism, and 5. phenomenalism. People think Wittgenstein refuted these views by showing, they believe, no word is learnable only by private ostensive definition. I defend these five views from Wittgenstein’s attack.
Pleasure is one of the strongest candidates for an occurrence that might be good, in some respect, unconditionally. Malicious pleasure is one of the most often cited alleged counter-examples to pleasure’s being an unconditional good. Correctly evaluating malicious pleasure is more complex than people realize. I defend pleasure’s unconditionally good status from critics of malicious pleasure.
This paper focuses on the issue of what to do if a couple who generates embryos chooses to lawfully, and in their (and my) view, ethnically discard those embryos. Specifically, is it appropriate to use the cells that come from “excess” embryos in medical research instead of discarding them when a couple has ceased trying to have any additional children?