The work of Gleason and of Kochen and Specker has been thought to refute a naïve realist approach to quantum mechanics. The argument of this paper substantially bears out this conclusion. The assumptions required by their work are not arbitrary, but have sound theoretical justification. Moreover, if they are false, there seems no reason why their falsity should not be demonstrable in some sufficiently ingenious experiment. Suitably interpreted, the work of Bell and Wigner may be seen to yield independent arguments (...) for the falsity of naïve realistic approach to quantum mechanics. Quantum mechanics is no more like classical statistical mechanics than its creators thought it was. (shrink)

Summary In this report on the present state of the discussion about the interpretation of quantum mechanics an attempt is made to provide an idea of the philosophical relevance of the foundations of physics. A simplified model of the measuring process is given which shows the difficulties in the interpretation of quantum mechanics. It is argued against Bohr's solution (also in a version of H. Putnam). Two examples show possible philosophical consequences of quantum mechanics: The variety of quantum logics challenges (...) the foundations of logic, the paradox of Einstein, Podolsky and Rosen (with Bell's inequality) may be interpreted along the lines of holism. Against alleged refutations of realism by means of quantum mechanics, a realist standpoint is maintained. A proper interpretation of quantum mechanics from an epistemological point of view seems still to be lacking. (shrink)

Recent discussions of experimental tests of the Sum Rule have been carried out in the context of the special circumstances attending the Cross-Ramsey experiment. A more general analysis of possible tests is presented. A technical mistake of Fine and Glymour concerned with a misunderstanding of the physics of the Cross-Ramsey experiment is explained and a detailed analysis of a thought experiment based on the Einstein-Podolsky-Rosen wave function is given. It is concluded, in agreement with Fine, that scattering experiments do not (...) test the Sum Rule as a principle which supplements standard quantum mechanics. (shrink)

In this paper I expound an argument which seems to establish that probabilism and special relativity are incompatible. I examine the argument critically, and consider its implications for interpretative problems of quantum theory, and for theoretical physics as a whole.

In this paper I put forward a new micro realistic, fundamentally probabilistic, propensiton version of quantum theory. According to this theory, the entities of the quantum domain - electrons, photons, atoms - are neither particles nor fields, but a new kind of fundamentally probabilistic entity, the propensiton - entities which interact with one another probabilistically. This version of quantum theory leaves the Schroedinger equation unchanged, but reinterprets it to specify how propensitons evolve when no probabilistic transitions occur. Probabilisitic transitions occur (...) when new "particles" are created as a result of inelastic interactions. All measurements are just special cases of this. This propensiton version of quantum theory, I argue, solves the wave/particle dilemma, is free of conceptual problems that plague orthodox quantum theory, recovers all the empirical success of orthodox quantum theory, and at the same time yields as yet untested predictions that differ from those of orthodox quantum theory. (shrink)

To the memory of John D. TrimmerThis paper assesses the impact of disjunctive facts on the quantum logic read off procedure. The purpose of the procedure is to transfer a significant quantum structure to a set of propositions; its first step is an attempt to discover that structure. Here I propose that disjunctive facts as traditionally conceived have blocked the procedure at its first step and have therefore subverted the best-known attempts to read off quantum logic. Recently however Allen Stairs (...) has proposed a view of disjunctive facts which re-establishes the possibility of reading off quantum logic. Both the traditional conception and Stairs’ revision of disjunctive facts are interesting in their own right, independent of quantum propositional logic. Too many things are called ‘quantum logic’. The term is disentangled and notation is fixed in this preliminary step which relies on basic lattice theory. (shrink)

In this report on the present state of the discussion about the interpretation of quantum mechanics an attempt is made to provide an idea of the philosophical relevance of the foundations of physics. A simplified model of the measuring process is given which shows the difficulties in the interpretation of quantum mechanics. It is argued against Bohr's solution (also in a version of H. Putnam). Two examples show possible philosophical consequences of quantum mechanics: The variety of quantum logics challenges the (...) foundations of logic, the paradox of Einstein, Podolsky and Rosen (with Bell's inequality) may be interpreted along the lines of holism. Against alleged refutations of realism by means of quantum mechanics, a realist standpoint is maintained. A proper interpretation of quantum mechanics from an epistemological point of view seems still to be lacking. In my childhood the legend was current, that only twelve men in the World understood Einstein's theory. Nowadays, relativity is quite tame; but I shall argue presently thatnobody yet understands the quantum theory. Howard Stein. (shrink)

The use of joint distribution functions for noncommuting observables in quantum thermodynamics is investigated in the light of L. Cohen's proof that such distributions are not determined by the quantum state. Cohen's proof is irrelevant to uses of the functions that do not depend on interpreting them as distributions. An example of this, from quantum Onsager theory, is discussed. Other uses presuppose that correlations betweenp andq values depend at least on the state. But correlations may be fixed by the state (...) even though the distribution varies from one ensemble to another represented by that state. Taking covariance as a measure of correlation, it is shown that the different commonly used joint distributions yield the same correlations for a given state. A general characterization is given for a family of distributions with this same covariance. (shrink)