Olimpia Lombardi

The core of the environment-induced decoherence program relies on the interaction between the system and its environment; this interaction leads interference to vanish with respect to a definite “preferred basis”. On the other hand, modal interpretations of quantum mechanics supply criteria to select the “preferred context”, where observables acquire definite values. The purpose of this paper is to show the compatibility between the modal interpretative framework and the results of the decoherence program, a compatibility that comes to the light when the Hamiltonian is conceived as the main character of the quantum play

Ilya Prigogine was not a systematic author: his ideas, covering a wide arch of areas, are dispersed in his many writings. In particular, his philosophical thought has to be reconstructed mainly on the basis of his works in collaboration with Isabelle Stengers: La Nouvelle Alliance ( 1979 ), Order out of Chaos ( 1984 ), and Entre le Temps et l’Éternité ( 1988 ). In this paper I undertake that reconstruction in order to argue that Prigogine’s position, when read in the light of Putnam’s internalist realism, can be characterized as an ontological pluralism. The main aim of this work is to show the striking parallelism between the philosophical views of Prigogine and Stengers and those of Hilary Putnam in Reason , Truth and History ( 1981 ). This task will lead me to critically review Prigogine’s general scientific program: the attempt to establish the foundations of objective irreversibility.

We propose a new quantum ontology, in which properties are the fundamental building blocks. In this property ontology physical systems are defined as bundles of type-properties. Not all elements of such bundles are associated with definite case-properties, and this accommodates the Kochen and Specker theorem and contextuality. Moreover, we do not attribute an identity to the type-properties, which gives rise to a novel form of the bundle theory. There are no “particles” in the sense of classical individuals in this ontology, although the behavior of such individuals is mimicked in some circumstances. This picture leads in a natural way to the symmetrization postulates for systems of many “identical particles”.

El objetivo del presente trabajo consiste en analizar las diferencias entre los enfoques de Boltzmann y de Gibbs respecto del problema de la irreversibilidad. Dicho análisis nos permitirá poner de manifiesto que, en las discusiones acerca de las condiciones necesarias para la irreversibilidad, no suele advertirse que la diferencia central entre los dos enfoques consiste en la utilización de diferentes conceptos de equilibrio y, por tanto, de irreversibilidad. Finalmente se argumentará que, si bien inicialmente ambos enfoques parecen por completo irreconciliables, existen condiciones físicas definidas bajo las cuales los resultados que proporcionan ambos marcos teóricos se aproximan lo suficiente como para ser considerados igualmente admisibles desde el punto de vista de la práctica de la física. /// The aim of this paper is to analyze the differences between the approaches of Boltzmann and Gibbs with respect to the problem of irreversibility. This analysis will allow us to show that, in the discussion about the necessary conditions for irreversibility, it goes often unnoticed that the main difference between the two approaches is the use of different concepts of equilibrium and, as a consequence, of irreversibility. Finally, we will argue that, although in principie both approaches seem completely irreconcilable, there are definite physical conditions under which the results provided by both theoretical frameworks are similar enough to be considered equally admissible for all practical purposes.

El propósito del presente artículo es evaluar en qué sentido y bajo qué condiciones la ergodicidad es relevante para explicar el éxito de la mecánica estadística. Se objeta la positión de quienes sostienen que la ergodicidad es irrelevante para tal explicatión, y se señala que las propiedades ergódicas desempeñan diferentes papeles en la mecánica estadística del equilibrio y en la descriptión de la evolución hacia el equilibrio: es posible prescindir de la ergodicidad en el primer caso pero no en el segundo. Sobre esta base, se reformularán las definiciones de ergodicidad y mezcla, relativizándolas a la macrovariable particular cuya evolución irreversible se desea describir. Finalmente, se enfatiza la importancia de tomar en cuenta la elaboratión de modelos para evaluar la utilizatión de los métodos de Gibbs. /// The aim of this paper is to consider in what sense and under what conditions ergodicity is relevant for explaining the success of Statistical Mechanics. We argue against those who claim that ergodicity is irrelevant to this explanation, by noting that ergodic properties play different roles in equilibrium Statistical Mechanics and in the description of the approach to equilibrium: it is possible to do without it in the first case but not in the second one. On this basis, we reformulate the definitions of ergodicity and mixing, relativizing them to the particular macrovariable whose irreversible evolution is to be described. Finally, we stress the relevance of taking into account model-construction for evaluating the use of Gibbs' methods.

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.

RESUMEN: El propósito del presente trabajo consiste en analizar los vínculos entre la interpretación modal-hamiltoniana de la mecánica cuántica y las transformaciones de Galileo, a fin de poner de manifiesto que el grupo de tales transformaciones permite reformular la regla de actualización de un modo más básico desde un punto de vista teórico, aplicable a otras teorías cuánticas. Además se argumentará que, bajo esta nueva forma, la regla de actualización manifiesta explícitamente su invariancia frente al grupo de Galileo.ABSTRACT: The purpose of the present work consists in analyzing the links between the modal-Hamiltonian interpretation of quantummechanics and the Galilean transformations, with the aim of showing that the group of such transformations allows to reformulate the actualization rule in a theoretically more basic way, applicable to other quantum theories. Moreover, it will be argued that, under this new form, the actualization rule explicitly manifests its invariance with respect to the Galilean group.

The many-faced relationship between chemistry and physics is one of the most discussed topics in the philosophy of chemistry. In his recent book Reducing Chemistry to Physics. Limits, Models, Consequences, Hinne Hettema conceives this relationship as a reduction link, and devotes his work to defend this position on the basis of a “naturalized” concept of reduction. In the present paper I critically review three kinds of issues stemming from Hettema’s argumentation: philosophical, scientific and methodological

El propósito del presente trabajo consiste en abordar la pregunta por la ontología de la química cuántica. Para ello nos concentraremos en el concepto de enlace químico desde la perspectiva de los dos enfoques a través de los cuales la ecuación de Schrödinger se aplica a los sistemas químicos moleculares: la teoría del enlace de valencia (EV) y la teoría del orbital molecular (OM). Sobre la base de la presentación de ambos enfoques y su comparación, señalaremos que, a pesar de su denominación tradicional, no pueden considerarse estrictamente como teorías científicas, sino que se ajustan mejor a la noción de modelo; en particular, son modelos que incorporan conceptos y leyes tanto del ámbito de la mecánica cuántica como del de la química estructural. Estas consideraciones nos permitirán argumentar que la química cuántica no posee un referente ontológico autónomo, sino que se trata de un ámbito científico cuya vigencia descansa sobre su éxito práctico en el cálculo y la predicción. Finalmente, indicaremos de qué modo los enfoques EV y OM del enlace químico abren una nueva perspectiva respecto de la noción misma de modelo en ciencias empíricas

Prigogine afirma que, en presencia de alta inestabilidad (caos), 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: (i) los argumentos de Prigogine en favor de tal tesis no son concluyentes, y (ii) 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 (chaos) makes the postulation of pointlike states and linelike trajectories in phase space a false idealization. In this paper we argue that (i) Prigogine’s arguments for this claim are not conclusive, and (ii) there are good reasons for retain the positing of pointlike states and linelike trajectories as a legitimate theoretical posit in statistical mechanics

En su libro "Time's Arrow and Archimedes' Point", Huw Price critica los argumentos de algunos cosmólogos contemporáneos acerca del origen cosmológico de la flecha del tiempo, quienes supuestamente no logran adoptar un punto de vista atemporal. En este artículo se analizan las criticas de Price a la propuesta de Stephen Hawking, argumentando que sus conclusiones se basan en supuestos cuestionables desde un punto de vista científico. Esta tarea abre el camino hacía un enfoque global no-entrópico de la flecha del tiempo, que permite establecer un nuevo diálogo con la propuesta de Price

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.

The modal-Hamiltonian interpretation belongs to the modal family of interpretations of quantum mechanics. By endowing the Hamiltonian with the role of selecting the subset of the definite-valued observables of the system, it accounts for ideal and non-ideal measurements, and also supplies a criterion to distinguish between reliable and non-reliable measurements in the non-ideal case. It can be reformulated in an explicitly invariant form, in terms of the Casimir operators of the Galilean group, and the compatibility of the MHI with the theory of decoherence has been proved. Nevertheless, perhaps its main advantage in the eyes of a scientist is given by its several applications to well-known physical situations, leading to results compatible with experimental evidence. The purpose of this paper is to add a new application to the list: the case of optical isomerism, which is a central issue for the philosophy of physics and of chemistry since it points to the core of the problem of the relationship between physics and chemistry. Here it will be shown that the MHI supplies a direct and physically natural solution to the problem, a solution that does not require putting classical assumptions in “by hand.”

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.