Olimpia Lombardi

In the present paper we address the problem of optical isomerism embodied in the socalled “Hund’s paradox”, which points to the difficulty to account for chirality by means of quantum mechanics. In particular, we explain the answer to the problem proposed by the theory of decoherence. The purpose of this article is to challenge this answer on the basis of a conceptual analysis of the phenomenon of decoherence, that reveals the limitations of the theory of decoherence to solve the difficulties posed by optical isomerism and, in general, by quantum measurement.

According to Zurek, decoherence is a process resulting from the interaction between a quantum system and its environment; this process singles out a preferred set of states, usually called “pointer basis”, that determines which observables will receive definite values. This means that decoherence leads to a sort of selection which precludes all except a small subset of the states in the Hilbert space of the system from behaving in a classical manner: environment-induced-superselection—einselection —is a consequence of the process of decoherence. The aim of this paper is to present a new approach to decoherence, different from the mainstream approach of Zurek and his collaborators. We will argue that this approach offers conceptual advantages over the traditional one when problems of foundations are considered; in particular, from the new perspective, decoherence in closed quantum systems becomes possible and the preferred basis acquires a well founded definition.

Some authors, inspired by the theoretical requirements for the formulation of a quantum theory of gravity, proposed a relational reconstruction of the quantum parameter-time—the time of the unitary evolution, which would make quantum mechanics compatible with relativity. The aim of the present work is to follow the lead of those relational programs by proposing a relational reconstruction of the event-time—which orders the detection of the definite values of the system’s observables. Such a reconstruction will be based on the modal-Hamiltonian interpretation of quantum mechanics, which provides a clear criterion to select which observables acquire a definite value and to specify in what situation they do so.

In this paper it will be argued that any realist interpretation of quantum mechanics intending to preserve the objectivity of the set of the definite-valued observables should require such a set to be invariant under the symmetry group of the theory. In particular, it will be shown that the natural way to reach this goal is to appeal to the Casimir operators of the Galilean group. Additionally, this idea will be generalized in two ways: by selecting the definite-valued observables of a system in quantum field theory as those represented by the Casimir operators of the Poincaré group, and by extending the strategy to gauge symmetries.

Although during the last decades the philosophy of chemistry has greatly extended its thematic scope, the main difficulties appear in the attempt to link the chemical description of atoms and molecules and the description supplied by quantum mechanics. The aim of this paper is to analyze how the difficulties that threaten the continuous conceptual link between molecular chemistry and quantum mechanics can be overcome or, at least, moderated from the perspective of BM. With this purpose, in “The quantum-mechanical challenges” section the foundational incompatibility between chemical and SQM descriptions will be briefly recalled. “Bohmian mechanics” section will be devoted to explain the main features of BM. In “Empirical equivalence and underdetermination” section, the consequences of the empirical equivalence between SQM and BM will be discussed. Finally, in the Conclusion, we will stress the scope of the obtained conclusions and the philosophical difficulties that still remain even after adopting BM for foundational purposes.

En el presente artículo abordaremos la cuestión del determinismo ontológico en física. Proponemos una elucidación del concepto de posibilidad que resulte útil para tratar el problema del determinismo ontológico en física, y mediante la cual pueda interpretarse el concepto de probabilidad de un modo signifi cativo para la práctica de la física teórica. Finalmente, los conceptos previamente elucidados se aplican a un caso paradigmático de la física, el de los sistemas altamente inestables, argumentando que en este ámbito determinismo e indeterminismo ontológicos pueden coexistir en un único sistema clásico.

The aim of the present paper is to supply an elucidation of the concept of information in the communicational context. For this purpose, two traditional interpretations of the concept of information, the epistemic and the physical interpretations, will be distinguished, and their specific problems will be considered. In particular, whereas the epistemic interpretation misses an essential feature of communication, the physical interpretation faces difficulties in the quantum domain. The final goal will be to argue that the difficulties of the physical interpretation can be overcome by means of a manipulability conception of causation.

In his recent Editorial Article, Jeffrey Seeman calls for the promotion of collaborative work among different disciplines, focusing on the case of the interaction between chemistry, the history of chemistry and the philosophy of chemistry. From a general viewpoint, it is difficult to disagree with this claim; moreover, the interest of scientists in the history and the philosophy of science is always welcome. However, the devil is in the details: there are several points that, we think, must be discussed more carefully with the aim of arriving at far-reaching conclusions.

The study of similarity is fundamental to biological inquiry. Many homology concepts have been formulated that function successfully to explain similarity in their native domains, but fail to provide an overarching account applicable to variably interconnected and independent areas of biological research despite the monistic standpoint from which they originate. The use of multiple, explicitly articulated homology concepts, applicable at different levels of the biological hierarchy, allows a more thorough investigation of the nature of biological similarity. Responsible epistemological pluralism as advocated herein is generative of fruitful and innovative biological research, and is appropriate given the metaphysical pluralism that underpins all of biology.

Prigogine afirma que, en presencia de alta inestabilidad, los estados puntuales y las trayectorias lineales en el espacio de las fases se convierten en una falsa idealización. En el presente trabajo se sostiene que: los argumentos de Prigogine en favor de tal tesis no son concluyentes, y hay buenas razones para retener la postulacion de estados puntuales y trayectorias lineales, en tanto conceptos teóricos legítimos en mecánica estadística.Prigogine asserts that the existence of radical instability makes the postulation of pointlike states and linelike trajectories in phase space a false idealization. In this paper we argue that Prigogine’s arguments for this claim are not conclusive, and there are good reasons for retain the positing of pointlike states and linelike trajectories as a legitimate theoretical posit in statistical mechanics.

To which ontological category do quantum systems belong? Although we usually speak of particles, it is well known that these peculiar items defy several traditional metaphysical principles. In the present chapter these challenges will be discussed in the light of certain distinctions usually not taken into account in the debate about the ontological nature of quantum systems. On this basis, it will be argued that an ontology of properties without individuals, framed in the algebraic formalism of quantum mechanics, provides adequate answers to the ontological challenges raised by the theory.What kind of item is a quantum system? In the practice of physics it is common to speak of quantum particles, as if they were items of a similar nature to classical items, but obeying different laws of motion. However, as is well known, quantum systems have such peculiar features that they challenge certain ontological principles and categories as understood in traditional metaphysics. In general, these features are analyzed in the context of the so-called problem of indistinguishability, which is a consequence of the particular statistical behavior of quantum systems. But the fact that certain items are “indistinguishable” is not the only difficulty to be overcome in order to elucidate the ontological category of quantum systems.

In this work we will deal only with the concept of information in the communicational context, in which information is primarily something that has to be transmitted for communication purposes. The aim of the paper is to consider some arguments traditionally put forward to support the idea that quantum information is qualitatively different than classical information. On the basis of the analysis of those arguments, we will conclude that there are no reasons to admit the existence of quantum information as qualitatively different from classical information: there is only one kind of information, physically neutral, which can be encoded by means of classical or of quantum states.

Although Bohr’s Correspondence Principle (CP) played a central role in the first days of quantum mechanics, its original version seems to have no present-day relevance. The purpose of this article is to show that the CP, with no need of being interpreted in terms of the quantum-to-classical limit, still plays a relevant role in the understanding of the relationships between the classical and the quantum domains. In particular, it will be argued that a generic version of the CP is very helpful in elucidating the physical meaning of the phenomenon of quantum decoherence.

This article focuses on the relationship between microevolution and macroevolution. The main purpose is to argue that up to the present time in the consolidation of the evolutionary synthesis macroevolution has been always conceived as dependent on microevolution. Such dependence was very clear in the synthesis, but seems to have been left aside by later authors. Nevertheless, we show that the criticisms of the synthesis since the decade of the 1970s did not modify that general trend: the new perspectives reproduced the dependence of macroevolution on microevolution by means of strategies different than those appealed to by the traditional synthesis.