Abner Shimony is one of the most eminent of present-day philosophers of science, whose work has exerted a profound influence in both the philosophy and physics communities. This two-volume 1993 collection of his essays written over a period of forty years explores the interrelations between science and philosophy. Shimony regards the knowing subject as an entity in nature whose faculties must be studied from the points of view of evolutionary biology and empirical psychology. He maintains that the twentieth century is (...) one of the great ages of metaphysics, given the deep implications of quantum mechanics, relativity theory and molecular biology. Nevertheless he rejects the thesis that mentality is entirely explicable in physical terms and argues that mind has a fundamental place in nature. Though distinguishing between values and scientifically established facts, Shimony holds that the sense of wonder cultivated by the natural sciences is one of the noblest of human values. (shrink)
Noncontextual hidden variables theories, assigning simultaneous values to all quantum mechanical observables, are inconsistent by theorems of Gleason and others. These theorems do not exclude contextual hidden variables theories, in which a complete state assigns values to physical quantities only relative to contexts. However, any contextual theory obeying a certain factorisability conditions implies one of Bell's Inequalities, thereby precluding complete agreement with quantum mechanical predictions. The present paper distinguishes two kinds of contextual theories, ‘algebraic’ and ‘environmental’, and investigates when factorisability (...) is reasonable. Some statements by Fine about the philosophical significance of Bell's Inequalities are then assessed. (shrink)
Many of the pioneers of quantum mechanics — notably Planck, Einstein, Bohr, de Broglie, Heisenberg, Schrodinger, Born, Jordan, Lande, Wigner, and London — were seriously concerned with philosophical questions. In each case one can ask a question of psychological and historical interest: was it a philosophical penchant which drew the investigator towards a kind of physics research which is linked to philosophy, or was it rather that the conceptual difficulties of fundamental physics pulled him willy-nilly into the labyrinth of philosophy? (...) I shall not undertake to discuss this question, but shall cite an opinion of Peter Bergmann, which I find congenial: he learned from Einstein that “the theoretical physicist is a philosopher in workingman’s clothes” (,q.v). (shrink)
The theory of natural selection is a rich systematization of biological knowledge without a first principle. When formulations of a proposed principle of natural selection are examined carefully, each is seen to be exhaustively analyzable into a proposition about sources of fitness and a proposition about consequences of fitness. But whenever the fitness of an organic variety is well defined in a given biological situation, its sources are local contingencies together with the background of laws from disciplines other than the (...) theory of natural selection; and the consequences of fitness for the long range fate of organic varieties are essentially applications of probability theory. Hence there is no role and no need for a principle of the theory of natural selection, and any generalities that may hold in that theory are derivative rather than fundamental. (shrink)
If quantum mechanics is interpreted as an objective, complete, physical theory, applying to macroscopic as well as microscopic systems, then the linearity of quantum dynamics gives rise to the measurement problem and related problems, which cannot be solved without modifying the dynamics. Eight desiderata are proposed for a reasonable modified theory. They favor a stochastic modification rather than a deterministic non-linear one, but the spontaneous localization theories of Ghirardi et al. and Pearle are criticized. The intermittent fluorescence of a trapped (...) atom irradiated by two laser beams suggests a stochastic theory in which the locus of stochasticity is interaction between a material system and the electromagnetic vacuum. (shrink)
Using an apparatus in which two scalers register decays from a radioactive source, an observer located near one of the scalers attempted to convey a message to an observer located near the other one by choosing to look or to refrain from looking at his scaler. The results indicate that no message was conveyed. Doubt is thereby thrown upon the hypothesis that the reduction of the wave packet is due to the interaction of the physical apparatus with the psyche of (...) an observer.A. Einstein(1). (shrink)
A combination of methodological considerations and propositions about the causal structure of spacetime provides a reply to Fine's criticisms of the "factorizability requirement" used in several versions of Bell's theorem. His proposal of "action in harmony" is criticized. Experimental tests are proposed for both the "synchronization models" and the "prism models", which Fine has invented as loopholes to Bell's theorem. A theorem of Suppes and Zanotti which purports to show the impossibility of hidden variables is criticized. One of their crucial (...) premisses seems to be justifiable only if one accepts a Parmenidean metaphysics. (shrink)
With the use of a suitable assumption about the structure of the class of experimental filters, it is shown that the sequence of alternating replicas of two filters is their greatest lower bound, as Jauch suggests. A generalization of his suggestion yields the greatest lower bound of a denumerable set of filters. The criteria of admissibility of filters are briefly discussed.
The Society for the Advancement of the Scientific World Conception has done me a great honor by inviting me to be the Sixth Vienna Circle Lecturer. The invitation has also stirred some deep emotions. A central figure of the Vienna Circle, Rudolf Carnap, was my revered teacher of philosophy at the University of Chicago in 1948–9 and later an informal adviser when I wrote a doctoral thesis at Yale University on inductive logic, and he was a friend during those years (...) and thereafter. I was not a disciple, but Carnap did not demand discipleship as a condition for admission to his seminars or to his friendship. He seemed to be baffled by the fact that despite my interest in mathematical logic and theoretical physics I proclaimed myself a metaphysicician and had even published an article in the first issue of The Review of Metaphysics. Carnap formulated a “principle of tolerance” as a philosophical maxim concerning rules of language, but he practiced a human and highly moral version of the principle of tolerance in his profoundly liberal social commitments and in his relations with his students. If he were here tonight, I would wish for his tolerance of the lapses of rigor and the flights of speculation to which he would be exposed. (shrink)
H.P. Stapp has proposed a number of demonstrations of a Bell-type theorem which dispensed with an assumption of hidden variables, but relied only upon locality together with an assumption that experimenters can choose freely which of several incompatible observables to measure. In recent papers his strategy has centered upon counterfactual conditionals. Stapp’s paper in American Journal of Physics, 2004, replies to objections raised against earlier expositions of this strategy and proposes a simplified demonstration. The new demonstration is criticized, several subtleties (...) in the logic of counterfactuals are pointed out, and the proofs of J.S. Bell and his followers are advocated. (shrink)
We investigate the thesis of Aharonov, Bergmann, and Lebowitz that time-symmetry holds in ensembles defined by both an initial and a final condition, called preand postselected ensembles. We distinguish two senses of time symmetry and show that the first one, concerning forward directed and time reversed measurements, holds if the measurement process is ideal, but fails if the measurement process is non-ideal, i.e., violates Lüders's rule. The second kind of time symmetry, concerning the interchange of initial and final conditions, fails (...) even in the case of ideal measurements. Bayes's theorem is used as a primary tool for calculating the relevant probabilities. We are critical of the concept that a pair of vectors in Hilbert space, characterizing the initial and final conditions, can be considered to constitute a generalized quantum state. (shrink)
2. "The first four chapters of this book are devoted to explaining the parts played by mathematical reasoning and by theoretical concepts and 'models' in the organization of a scientific theory". In short, this part of Scientific Explanation attempts to show how a modern empiricist can recognize the role of reason in science. The main theses in these chapters are as follows.
A corollary of Gleason's theorem asserts that if the lattice of propositions of a physical system is isomorphic to the lattice of subspaces of a Hilbert space of dimension greater than two, then there is no probability measure that assigns only the values 1 and 0 (truth and falsity, respectively) to each of the propositions. Belinfante outlined an elegant geometrical proof of this corollary but relied upon an unrigorous measure-theoretical statement. An amplified geometrical proof is given along Belinfante's lines, but (...) dispensing with measure theory. (shrink)
An extremum principle was postulated by Horne, Finkelstein, Shull, Zeilinger, and Bernstein in order to derive the physically allowable parameters for sinusoidal standing waves governing a neutron in a crystal which is immersed in a strong external magnetic field: “the expectation value of the total potential 〈V〉 is an extremum.” We show that this extremum principle can be obtained from the variational principle used by Schrodinger to derive his nonrelativistic wave equation. We rederive the solutions found by the above-mentioned authors (...) as well as some additional solutions. (shrink)
The idea of ensembles which are both pre- and post-selected was introduced by Aharonov, Bergmann, and Lebowitz and developed by Aharonov and his school. To derive formulae for the probabilities of outcomes of a measurement performed on such an ensemble at a time intermediate between pre-selection and post-selection, the latter group introduces a two-vector formulation of quantum mechanics, one vector propagating in the forward direction in time and one in the backward direction. The formulae which they obtain by this radical (...) generalization are vindicated by a rigorous derivation using Bayes’s theorem together with standard quantum mechanical predictions regarding ensembles that are only pre-selected. Their own two-vector derivation, however, suffers from a serious lacuna. (shrink)