Project

A modal interpretation for the quantum ontology

 

Philosophy of Science Group

GFC

FCEN - UBA

 
 

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INTERNAL SEMINARS

     
 
     
       
  June 2017

Seminar dictated by Joseph Berkovitz on June 15th 2017.

Title: On de Finetti’s Instrumentalist Philosophy of Probability

Abstract: De Finetti is commonly conceived as providing an operational, behaviorist definition of degrees of belief and accordingly of probabilities. His concept of probability is usually criticized because considered too permissive, licensing imprudent epistemology.
I will argue that these objections misinterpret central aspects of de Finetti’s philosophy of probability. In particular, they overlook de Finetti’s instrumentalist philosophy of probability.
 

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  May 2017

Seminar dictated by Olimpia Lombardi on May 04th 2017.

Title: The Modal-Hamiltonian Interpretation: measurement, invariance and ontology

Abstract: The Modal-Hamiltonian Interpretation (MHI) of quantum mechanics belongs to the modal family: it is a realist, non-collapse interpretation according to which the quantum state describes the possible properties of a system but not its actual properties. In particular, the Hamiltonian of the closed quantum system plays a decisive role in the rule that selects the definite-valued observables of the system. In this presentation I will focus on three issues:
a) The MHI is effective for solving the measurement problem, both in its ideal and its non-ideal versions. It accounts for well-known physical situations by conceiving measurement as a process that breaks the symmetry of the Hamiltonian and, then, turns an otherwise non definite-valued observable into a definite-valued and empirically accessible observable.
b) The MHI can be reformulated under an explicitly Galilean-invariant form in terms of the Casimir operators of the Galilean group, leading to results that agree with usual assumptions in the practice of physics. Then, any realist interpretation that intends to preserve the Galilean invariance of the set of definite-valued observables may not stand very far from the MHI.
c) According to the MHI, quantum systems are not individuals, but bundles of the type-properties represented by the system’s observables. In this ontology of properties, indistinguishability is no longer a relationship between individual particles, but an internal symmetry of a whole system, and the symmetry of the states is not the result of an ad hoc symmetrization, but is due to ontological reasons, that is, to the structure of the ontology itself.
 

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  April 2017

Seminar dictated by Mariana Córdoba y Juan Camilo Martínez González on April 20th 2017.

Title: Inter-theoretical relations in chemistry: the case of electronegativity

Abstract: The relation among chemistry and physics is one of the most maturely discussed issues in current philosophy of chemistry. Although the discussion focused traditionally on the possibility of determine inter-theoretical links between the disciplines, during the last years the question about the reference of the concepts involved in theories has been imposed. Hence, the debate has entered in an ontological realm. This was the case of the concept of orbital, chemical element and covalent chemical bond. Within the frame of this debate, some philosophical problems regarding quantum chemistry must be analyzed. Quantum chemistry deals with the application of quantum physics to the description of molecules’ behavior and properties.
In this presentation, we will consider an important chemical property: electronegativity. We will analyze if it is possible to reduce the concept of electronegativity to a quantum mechanical concept. In order to do this, we will explore how models of electronegativity are built in quantum chemistry and which is the relation among them and quantum mechanics laws, particularly approximative systems used to solve Schrödinger’s equation.
 

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  March 2017

Seminar dictated by Mario Natiello March 23rd 2017.

Title: Del idealismo kantiano a la especulación pragmática. El recorrido que vio el nacimiento de la física teórica, de Ampère y Maxwell a Lorentz

Abstract: En este trabajo haremos una revisión del desarrollo del electromagnetismo en el siglo XIX. Mostraremos las múltiples versiones y modificaciones que dieron lugar a la mutilación de las ecuaciones de Maxwell. También estudiaremos las consecuencias filosóficas de este desarrollo.
 

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  October 2016

Seminar dictated by Jesus Alberto Jaimes Arriaga October 27th 2016.

Title: An epistemological analysis of the Quantum Theory of Atoms and Molecules and its role in the definition of molecular structure

Abstract: A modern theory of molecular structure that proposes a complete reduction of chemistry to physics is the quantum theory of atoms and molecules (QTAIM). This theory is based on the idea that a molecule is a collection of atoms, and each atom contributes to the properties of the whole system. The idea is feasible thank to the existence of a zero-flow surface that limits each atom within a molecule. Likewise, this surface is a topological property of the electron density and, in this respect, this topology plays an important rol in the definition of molecular structure, since it involves the concepts of atom, bond, structure and structural stability. On the other hand, QTAIM is built on a strictly mathematical structure, base on physical theorems like the viral theorem, the Feynman force theorem and the Ehrenfest force theorem. With the help of these theorems one is able to understand and predict the properties of a system. Thus the theory offers as a whole a possibility to establish a link between the language of chemistry and that of physics.
 

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  October 2016

Seminar dictated by Patricia Palacios October 06th 2016.

Title: Emergence and reduction in physics

Abstract: In this presentation we will review the different types of emergencies that are defined in the philosophy of science. We will also discuss the paradigmatic cases of reduction, and the cases that are problematic in the philosophy of physics. Finally we present a new form of "modified reductionism" that could solve the problems of traditional reductionism.
 

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  September 2016

Seminar dictated by Erick Rubio September 08th 2016.

Title: Ontological aspects on which complexity falls in the study of a biological system

Abstract: The word "Complexity", used for the study of a system, be it abstract or material, can adopt different interpretations depending on whether it is brought to a sphere of ontological considerations or epistemological considerations. In a sphere of ontological considerations, one that interests us here, "Complexity" usually appears linked to structural, functional or organizational aspects. The aim of this work is to articulate these considerations in the query of whether the evolutionary process has favored in some sense an increase of complexity in certain biological items.
 

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  August 2016

Seminar dictated by Sebastian Fortin August 18th 2016.

Title: Relationship between chemistry and physics from Bohmian mechanics

Abstract: In this work we propose a perspective different from the traditional one to analyse philosophical problems in quantum chemistry. We claim that the introduction of the Quantum Theory of Motion may clarify some problems and to dissolve others. The possibility of definite positions for fixed nuclei simplifies the interpretation of the approximations in quantum chemistry. On the other hand this theory allows us to analyse the position of an electron in a chemical bond. In the particular case of the simple H-H covalent bond, computations lead to conclude that the electrons are in the middle of the two nuclei. In this way, we recover the “picture” of the classical chemistry viewpoint.
As a conclusion, we propose to explore the possibility that, from the conceptual point of view, the Quantum Theory of Motion be a more adequate theory for quantum chemistry.
 

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  July 2016

Seminar dictated by Stephan Hartmann July 11th 2016.

Title: Assessing Scientific Theories

Abstract:

- Science changed considerably over the last decades, and so did the methodology of science.
- Non-empirical ways of assessing scientic theories (such as the NAA) raise a number of interesting philosophical issues.
- Deductivist accounts of confirmation and corroboration cannot accommodate the NAA.
- Hence, if one does not want to dismiss this kind of reasoning, then an alternative to deductivism is needed.
- The NAA can be analyzed in the Bayesian framework and we have investigated under which conditions it is a good argument.
- Hence, we do not need a new methodology of science (as Ellis and Silk suggest): The Bayesian framework is exible enough.
- Further indirect ways of assessing scientific theories, such as analogue simulations, can be analyzed similarly.
- Are there alternatives ways of modeling the NAA? { I tried to find one, but so far without any success...

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  June 2016

Seminar dictated by Hernán Accorinti June 16th 2016.

Title: Theories and models: an approach from quantum chemistry

Abstract: In the twentieth century, theoretical physics was implicitly adopted as the paradigm for the philosophy of science. This led to a theory-centered perspective, according to which scientific knowledge is primarily encoded in theories, whereas models only appear in specific applications. The present work tries to provide a fresh perspective to the debate by considering an example coming from quantum chemistry.
According to the traditional conceptions of scientific theories, theories apply to particular situations through the use of specific models. This supposes that models depend on theories because they are designed to make the application of the theory possible. Thus, models in science are merely mediators between theories and reality. From this viewpoint, a model is always a model of a certain theory because it is its “truth-maker”.
This latter position was challenged by the so-called “toolbox” conception of scientific theories, which, from an instrumentalist stance, calls into question the dependence of models on a specific theory.
The purpose of the present paper is to participate in the debate in two interrelated steps:
(i) First, we analyze the discussions around the London brothers’ model from a critical viewpoint. Our aim is to show that the debate has reached a kind of dead end as the consequence of disagreements about the interpretation of the very notion of independence and its role in the constitution of scientific models.
(ii) Second, we intend to contribute to find a way out of the dead end by appealing to a new example, not yet sufficiently discussed in the current literature: the case of the molecular models used in quantum chemistry. Those models integrate two incompatible theoretical domains: quantum and classical.
The analysis of the molecular models of quantum chemistry supplies a new perspective to address the problem of the relation between theories and models. This perspective shows that the independence of models from theories cannot be considered, as the traditional view holds, as a merely relative and historical situation that will be overcome with further theoretical development. By contrast, the case of models in quantum chemistry reveals a conceptual independence that is constitutive of the modeling process.

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  May 2016

Seminar dictated by Manuel Herrera on May 19th 2016.

Title: Physical Causality , Conserved Quantities and General Relativity

Abstract: The Phil Dowe’s Conserved Quantities theory (CCT) reduces the causal interaction and causal processes to exchange and possession of conserved quantities, respectively; that is, amounts which are governed by conservation laws. CCT helps explain physical phenomena without major problems in the context of newtonian mechanics and Special Relativity. However, it is possible to identify some inconsistencies when CCT is applied in the field of General Relativity (GR). These difficulties are due to genuine there are drawbacks to enunciate principles of conservation within the framework of the GR. This research aims to provide some details and definitions that will allow the CCT correct application in the context of the GR.

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  April 2016

Seminar dictated by Juan Camilo Martínez Gonzáles and Mariana Córdoba on April 14th 2016.

Title: Inter-theoretical relations in chemistry: the case of electronegativity

Abstract: The relation among chemistry and physics is one of the most maturely discussed issues in current philosophy of chemistry. Although the discussion focused traditionally on the possibility of determine inter-theoretical links between the disciplines, during the last years the question about the reference of the concepts involved in theories has been imposed. Hence, the debate has entered in an ontological realm. This was the case of the concept of orbital, chemical element and covalent chemical bond. Within the frame of this debate, some philosophical problems regarding quantum chemistry must be analyzed. Quantum chemistry deals with the application of quantum physics to the description of molecules’ behavior and properties. In this presentation, we will consider an important chemical property: electronegativity. We will analyze if it is possible to reduce the concept of electronegativity to a quantum mechanical concept. In order to do this, we will explore how models of electronegativity are built in quantum chemistry and which is the relation among them and quantum mechanics laws, particularly approximative systems used to solve Schrödinger’s equation.
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  March 2016

Seminar dictated by Cristian Lopez on March 31st 2016.

Title: What Is There Inside the Great Smoky Dragon? Delayed-Choice Experiments from a Modal Ontology of Properties

Abstract: It is usually claimed that delayed-choice experiments challenge any realistic interpretation, encouraging an anti-realistic approach strongly linked to complementarity. In this presentation, we shall support a realistic point of view to cope with quantum-delayed choice based on a modal ontology of properties. We shall argue that whereas quantum delayed-choice experiments are a tough nut to crack for an ontology of individuals, the paradoxical aspects dissolve when a modal ontology of properties for quantum mechanics is adopted.

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  February 2016

Seminar dictated by Dr. Pablo Razeto Barry on February 25th 2016.

Title: Mass as an ontological emergent property

Abstract: In this talk I will try to show if it is possible to think of a mass as an ontological emergent property. Due to this, firstly I will review the problem of equivalence of mass and energy trying to give an alternative theory about it. Secondly I will review different meaning of the concept of emergent, given as instance for Bunge and Kim. The aim will be to give a new definition of ontological emergent property neither trivial nor empty and to present a clear scientific case of it too. Indeed I will try to show in which sense we can say that mass is an ontologically emergent property with respect to energy under the light of special relativity and quantum field theory..

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  2015

October 15, 2016: Mariana Córdoba and Juan Camilo Martínez González presented his work “Clases naturales en química” (“Natural kinds in chemistry”).


November 12: Gilberto Castrejón (student from the Universidad Nacional Autónoma de México, making a stay in the context of our group) presented the progress of his PhD thesis.


December 10: Prof. Hernán Solari (full professor of the Department of Physics of the Faculty of Exact and Natural Sciences of the University of Buenos Aires), was invited to present his talk “Acerca de la construcción de la relatividad especial” (About the construction of special relativity”).
 

 
 
 
 
 
                   
 
 
 
 

Philosophy of Science Group, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires - Ciudad Universitaria, Pabellón II / Buenos Aires, Argentina