In orthodox quantum mechanics, it has virtually become the custom to identify properties of a physical system with operationally testable propositions about the system. The causes and consequences of this practice are explored mathematically in this paper. Among other things, it is found that such an identification imposes severe constraints on the admissible states of the physical system.

Piron's axioms for a realistically interpreted quantum mechanics are analyzed in detail within the context of a formal mathematical structure expressed in the conventional set-theoretic idiom of mathematics. As a result, some of the serious misconceptions that have encouraged recent criticisms of Piron's axioms are exposed.

In this paper we attempt to analyze the physical and philosophical meaning of quantum contextuality. We will argue that there exists a general confusion within the foundational literature arising from the improper “scrambling” of two different meanings of quantum contextuality. While the first one, introduced by Bohr, is related to an epistemic interpretation of contextuality which stresses the incompatibility of measurement situations described in classical terms; the second meaning of contextuality is related to a purely formal understanding of contextuality as (...) exposed by the Kochen–Specker theorem which focuses instead on the constraints of the orthodox quantum formalism in order to interpret projection operators as preexistent or actual properties. We will show how these two notions have been scrambled together creating an “omelette of contextuality” which has been fully widespread through a popularized “epistemic explanation” of the KS theorem according to which: The measurement outcome of the observableAwhen measured together withBor together withCwill necessarily differ in case\, and\. We will show why this statement is not only improperly scrambling epistemic and formal perspectives, but is also physically and philosophically meaningless. Finally, we analyze the consequences of such widespread epistemic reading of KS theorem as related to statistical statements of measurement outcomes. (shrink)

In this paper we provide a general account of the causal models which attempt to provide a solution to the famous measurement problem of Quantum Mechanics. We will argue that—leaving aside instrumentalism which restricts the physical meaning of QM to the algorithmic prediction of measurement outcomes—the many interpretations which can be found in the literature can be distinguished through the way they model the measurement process, either in terms of the efficient cause or in terms of the final cause. We (...) will discuss and analyze why both, ‘final cause’ and ‘efficient cause’ models, face severe difficulties to solve the measurement problem. In contradistinction to these schemes we will present a new model based on the immanent cause which, we will argue, provides an intuitive understanding of the measurement process in QM. (shrink)

SummaryThe Bohr‐Einstein debate on the interpretation of quantum mechanics may be viewed as a discussion on the epistemological status of knowledge gained by physics. It is shown that in fact the advent of quantum theory has led, in a new context, to an old philosophical controversy between epistemological realism and phenomenalism . An inquiry into this controversy, taking into account the contemporary understanding of quantum mechanics based on the axiomatic study of its foundations, leads to the conclusion that contrary to (...) widespread opinion, it is perfectly possible to formulate quantum mechanics in an entirely realistic manner according to the postulate of Einstein. We demonstrate that Bohr's episteme‐logy, in which the role of experimental arrangements in the physical description is taken as a starting point, does not necessarily imply phenomenlism, but may be justifiably considered as a complementary standpoint to the realistic epistemology of Einstein, which is based on the notion of a mental construction which pictures reality. (shrink)

The mathematical description of the three distinct fundamental notions of “individual sample” of “preparing procedure,” and of “Piron's state” of a physical entity are precisely introduced in the framework of the Piron's “preparation-question structure” (without specific axioms C, P, A) based on Ludwig's “selection structure.” We compare our realization of the above notions with a similar use of the standard terminology of the “Geneva School” adopted by Pykacz and Santos in a recent paper.

On the basis of Mackey's axiomatic approach to quantum physics or, equivalently, of a “state-event-probability” (SEVP) structure, using a quite standard “fuzzification” procedure, a set of unsharp events (or “effects”) is constructed and the corresponding “state-effect-probability” (SEFP) structure is introduced. The introduction of some suitable axioms gives rise to a partially ordered structure of quantum Brouwer-Zadeh (BZ) poset; i.e., a poset endowed with two nonusual orthocomplementation mappings, a fuzzy-like orthocomplementation, and an intuitionistic-like orthocomplementation, whose set of sharp elements is an (...) orthomodular complete lattice. As customary, by these orthocomplementations the two modal-like necessity and possibility operators are introduced, and it is shown that Ludwig's and Jauch-Piron's approaches to quantum physics are “interpreted” in complete SEFP. As a marginal result, a standard procedure to construct a lot of unsharp realizations starting from any sharp realization of a fixed observable is given, and the relationship among sharp and corresponding unsharp realizations is studied. (shrink)

The following analysis attempts to provide a general account of the multiple solutions given to the quantum measurement problem in terms of causality. Leaving aside instrumentalism which restricts its understanding of quantum mechanics to the algorithmic prediction of measurement outcomes, the many approaches which try to give an answer can be distinguished by their explanation based on the efficient cause —recovering in this way a classical physical description— or based on the final cause —which goes back to the hylomorphic tradition. (...) Going beyond the limits of these two schemes we call the attention to an ‘inversion of the measurement problem’ and its proposed solution based on the immanent cause. By replacing both the final and efficient causes by the immanent cause we attempt to lay down new conditions for representing quantum superpositions in a realist way which coherently relates the quantum formalism with outcomes. (shrink)

In this paper we compare two different notions of 'power', both of which attempt to provide a realist understanding of quantum mechanics grounded on the potential mode of existence. For this propose we will begin by introducing two different notions of potentiality present already within Aristotelian metaphysics, namely, irrational potentiality and rational potentiality. After discussing the role played by potentiality within classical and quantum mechanics, we will address the notion of causal power which is directly related to irrational potentiality and (...) has been adopted by many interpretations of QM. We will then present the notion of immanent power which relates to rational potentiality and argue that this new concept presents important advantages regarding the possibilities it provides for understanding in a novel manner the theory of quanta. We end our paper with a comparison between both notions of 'power', stressing some radical differences between them. (shrink)