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)

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)

One of the most interesting programs in the foundations of quantum mechanics is the realist quantum logic approach associated with Putnam, Bub, Demopoulos and Friedman (and which is the focus of my own research.) I believe that realist quantum logic is our best hope for making sense of quantum mechanics, but I have come to suspect that the usual version may not be the correct one. In this paper, I would like to say why and to propose an alternative.

Anti-realism is plagued by Fitch’s paradox: the remarkable result that if one accepts that all truths are knowable, minimal assumptions about the nature of knowledge entail that every truth is known. Dorothy Edgington suggests to address this problem by understanding p is knowable to be a counterfactual claim, but her proposal must contend with a forceful objection by Timothy Williamson. I revisit Edgington’s basic idea and find that Williamson’s objection is obviated by a refined understanding of counterfactual knowability that is (...) grounded in possible courses of inquiry. I arrive at a precise definition of knowability that is not just a technical avoidance of paradox, but is metaphysically sound and does justice to the anti-realist idea. (shrink)

Anti-exceptionalism about logic is the Quinean view that logical theories have no special epistemological status, in particular, they are not self-evident or justified a priori. Instead, logical theories are continuous with scientific theories, and knowledge about logic is as hard-earned as knowledge of physics, economics, and chemistry. Once we reject apriorism about logic, however, we need an alternative account of how logical theories are justified and revised. A number of authors have recently argued that logical theories are justified by abductive (...) argument (e.g. Gillian Russell, Graham Priest, Timothy Williamson). This paper explores one crucial question about the abductive strategy: what counts as evidence for a logical theory? I develop three accounts of evidential confirmation that an anti-exceptionalist can accept: (1) intuitions about validity, (2) the Quine-Williamson account, and (3) indispensability arguments. I argue, against the received view, that none of the evidential sources support classical logic. (shrink)

ABSTRACT What do we disagree about when we disagree about logic? On the face of it, classical and nonclassical logicians disagree about the laws of logic and the nature of logical properties. Yet, sometimes the parties are accused of talking past each other. The worry is that if the parties to the dispute do not mean the same thing with ‘if’, ‘or’, and ‘not’, they fail to have genuine disagreement about the laws in question. After the work of Quine, this (...) objection against genuine disagreement about logic has been called the meaning-variance thesis. We argue that the meaning-variance thesis can be endorsed without blocking genuine disagreement. In fact, even the type of revisionism and nonapriorism championed by Quine turns out to be compatible with meaning-variance. (shrink)

In this paper a propositional logic of viewpoints is presented. The language of this logic consists of the usual modal operatorsL (of necessity) andM (of possibility) as well as of two new operatorsA andR. The intuitive interpretations ofA andR are from all viewpoints and from some viewpoint, respectively. Semantically the language is interpreted by using Kripke models augmented with sets of viewpoints and with a new alternativeness relation for the operatorA. Truth values of formulas are evaluated with respect to a (...) world and a viewpoint. Various axiomatizations of the logic of viewpoints are presented and proved complete. Finally, some applications are given. (shrink)

The paper, in Part 1, is devoted to discussing the underlying logic and algebra of the classical mechanics and quantum mechanics, their syntax and semantics, the reasons for their differences and the diagrammatic representations of the two. This part of the paper also demonstrates that there are several puzzling characters of microphysical phenomena by alluding to the relevant details of the double-slit experiment. These counterintuitive results of the experiment make it difficult to explain the empirical success and realist commitments of (...) quantum mechanics. The second part, Part 2, of the paper is concerned with the question as to how conceptual schemes of scientists interact with the world such that the problem of new meaning and reference of the microphysical terms could be determined. The paper refrains from having a general discussion on Realism and do not venture into a comprehensive survey and critique of all known varieties of realistic interpretations. It selects only a few forms of realism (based on the reasons given) in investigating microphysical phenomena forming part of QM. These selected forms of realism explain how does conceptual scheme/terms in scientific theory hookup to the objects and their relations in the world based on the model-theoretic character of the scientific theory and causal rigidified descriptivism of scientific terms (vide Putnam) as well as scientist’s interaction with the world, say, in the “instrumental context of laboratory” (vide Heelan) such that the problem of meaning and reference could be resolved. The paper claims that convergence of the two views may result in a particular form of realism, the Hermeneuticized Internal Realism, appropriate for the science of microphysical phenomena. (shrink)

In a reply to Nicholas Maxwell, Stein has proved that Minkowski spacetime can leave room for the kind of indeterminateness required both by certain interpretations of quantum mechanics and by objective becoming. By examining the consequences of outcome dependence in Bell-type experiments for the co-determinateness of spacelike-related events, I argue that the only becoming relation that is compatible with both causal and noncausal readings of the quantum correlations is the universal relation. This result might also undermine interpretations of quantum mechanics (...) requiring non-epistemically indeterminate states before measurement and hyperplane-dependent wave collapse. (shrink)

The search for a coherent and fertile interpretation of quantum mechanics [QM] with collapse of the wave function is currently a hot topic. This paper focuses on the following sets of related issues: 1) In what sense, if any, do collapse theories constitute a view of the quantum world induced “from the practices-up”? [Here and throughout the paper the term “a view from the practices-up” will mean a view induced from the practices of scientists working on specific problems.] 2) What (...) general description does a collapse variant of QM yield of the physical world? What interpretative problems, if any, does it solve? How exactly does it differ from current mainstream versions of QM? What problems does it face? How serious are these problems in light of current background knowledge?. 3) In our present scientific and philosophical circumstances, what, if anything, makes the search for collapse theories an attractive program? (shrink)

Hugh Everett III proposed that a quantum measurement can be treated as an interaction that correlates microscopic and macroscopic systems—particularly when the experimenter herself is included among those macroscopic systems. It has been difficult, however, to determine precisely what this proposal amounts to. Almost without exception, commentators have held that there are ambiguities in Everett’s theory of measurement that result from significant—even embarrassing—omissions. In the present paper, we resist the conclusion that Everett’s proposal is incomplete, and we develop a close (...) reading that accounts for apparent oversights. We begin by taking a look at how Everett set up his project—his method and his criterion of success. Illuminating parallels are found between Everett’s method and then-contemporary thought regarding inter-theoretic reduction. Also, from unpublished papers and correspondence, we are able to piece together how Everett judged the success of his theory of measurement, which completes our account of his intended contribution to the resolution of the quantum measurement problem. (shrink)

Hugh Everett III proposed that a quantum measurement can be treated as an interaction that correlates microscopic and macroscopic systems—particularly when the experimenter herself is included among those macroscopic systems. It has been difficult, however, to determine precisely what this proposal amounts to. Almost without exception, commentators have held that there are ambiguities in Everett’s theory of measurement that result from significant—even embarrassing—omissions. In the present paper, we resist the conclusion that Everett’s proposal is incomplete, and we develop a close (...) reading that accounts for apparent oversights. We begin by taking a look at how Everett set up his project—his method and his criterion of success. Illuminating parallels are found between Everett’s method and then-contemporary thought regarding inter-theoretic reduction. Also, from unpublished papers and correspondence, we are able to piece together how Everett judged the success of his theory of measurement, which completes our account of his intended contribution to the resolution of the quantum measurement problem. (shrink)

A Quantum-Mechanical automation, equipped with mechanisms for the measurement and the recording and the prediction of certain physical properties of the world, is described. It is inquired what sort of empirical description such an automation would produce of itself. It turns out that this description would be a very novel one, one such as was never imagined in the conventional discussions of measurement.

The philosophical debate about quantum logic between the late 1960s and the early 1980s was generated mainly by Putnam's claims that quantum mechanics empirically motivates introducing a new form of logic, that such an empirically founded quantum logic is the `true' logic, and that adopting quantum logic would resolve all the paradoxes of quantum mechanics. Most of that debate focussed on the latter claim, reaching the conclusion that it was mistaken. This chapter will attempt to clarify the possible misunderstandings surrounding (...) the more radical claims about the revision of logic, assessing them in particular both in the context of more general quantum-like theories (in the framework of von Neumann algebras), and against the background of the current state of play in the philosophy and interpretation of quantum mechanics. Characteristically, the conclusions that might be drawn depend crucially on which of the currently proposed solutions to the measurement problem is adopted. (shrink)

This article is devoted to give reasons against the naturalization of logic, in a sense which entails a revision of this science. The paper criticizes each historical important attempt to revise logical laws – intuitionism, quantum logic, alternative logics – and also it tries to argue that the explanation problem of quantum mechanics has nothing to do with a naturalization of logic.