As with any scientific revolution, quantum mechanics entailed a profound revision of our fundamental epistemological concepts and also of our worldview as a whole. This was the case for the concepts of causality and reality. Around these concepts, there arose in the third decade of the last century a heated debate in which almost all the scientists and philosophers of the time took part and which in a certain sense is still going on today. The Author provides a reconstruction of the various different positions, from the conservative attempt to defend determinism to the most radical stochastic positions, and singles out in Ernst Cassirer’s solution the most convincing approach.
As with any scientific revolution, quantum mechanics entailed a profound revision of our fundamental epistemological concepts and also of our worldview as a whole. This was the case for the concepts of causality and reality. Around these concepts, there arose in the third decade of the last century a heated debate in which almost all the scientists and philosophers of the time took part and which in a certain sense is still going on today. The Author provides a reconstruction of the various different positions, from the conservative attempt to defend determinism to the most radical stochastic positions, and singles out in Ernst Cassirer’s solution the most convincing approach.
Quantum mechanics constituted a great scientific and cultural revolution that profoundly changed our approach to the study of the microscopic and subatomic world. The birth and evolution of the theories of quantum mechanics are revived through the personal and scientific history of the protagonists, their attempts and their working hypotheses, the discoveries, doubts and discussions. The substantially counterintuitive concepts of the new mechanics have redesigned the meaning of our knowledge of the world of atoms; particular attention is then paid to the impact that this new vision of the microscopic world has had on chemistry and our knowledge of the structure and reactivity of atoms and molecules.
In the 19th century, determinism was often seen as a presupposition of scientific thinking, although its validity was not universally accepted among scientists and philosophers. There were different conceptions of causality, and the concept of cause was often linked to that of force or energy; but toward the end of the 19th century, the causal conception of forces was increasingly criticised and some argued that the concept of cause should be abandoned altogether. After the development of the modern theory of quantum mechanics in 1925, many physicists and philosophers claimed that this theory implied an overthrow of the classical conception of causality; however, only few authors abandoned causality altogether. The debate of the implications of quantum mechanics for causality soon became muddled because of the many different meanings attached to the term “causality”.
This work presents a historical-epistemological analysis of the foundations of quantum mechanics. From a philosophical point of view, the relationships between quantum mechanics and scientific realism are highlighted, as well as the influence of the neo-positivist philosophy of the first decades of the 20th century. The great significance of measurement in the context of quantum mechanics is underlined, as an essential element in providing a coherent description of reality moving from the microcosm to the macrocosm, as well as the role that the measurement apparatus and the consciousness of the observer assume during the act of measurement, the ontological problem, the problem of the objectification of the wave function and the problem of the definition of discernibility. This is followed by an overview of the most important alternative proposals to the standard interpretation (Copenhagen interpretation), with particular reference to hidden variable theories, and other alternatives to standard quantum mechanics that profoundly modify the vision of reality, such as the Everett’s many-worlds theory, the QBism, the unified holistic approach.
In questa tesi sostengo che l’interpretazione modale della Meccanica Quantistica, almeno nella versione di van Fraassen del 1991 ed in quella di Kochen-Dieks, non soddisfa le ipotesi del teorema PBR. Tale teorema dimostra che una certa classe di interpretazioni (specificamente i modelli ontologici ψ-epistemici e ψ-indipendenti) porta a prevedere risultati sperimentali in contrasto con quelli previsti dalla Meccanica Quantistica teorizzata da von Neumann, e dunque sia da rigettare.
In particolare dimostro, in contrasto con quanto suggerito da Leifer in un articolo apparso sulla rivista Quanta nel 2014, che l’interpretazione modale e un modello ontologico ψ-epistemico. Tuttavia esso e anche ψ-dipendente, dunque il teorema PBR non invalida questa interpretazione.
In riferimento al titolo, l’interpretazione modale prevede che lo stato quantico sia in parte reale ed in parte epistemico, e nella tesi esporro in che senso. Il totale realismo sulla funzione d’onda prescritto dal teorema PBR e invece incompatibile con una sua interpretazione modale.
In this thesis I prove that modal interpretation of Quantum Mechanics, at least in the van Frassen’s version and in Kochen-Dieks’ one, doesn’t satisfy the hypothesis of PBR theorem. This theorem demonstrates that a certain class of interpretations (namely onthological ψ-epistemic ψ-independent models) predict experimental results in contrast with the ones predicted by Quantum Mechanics as theorized by von Neumann, and so is to be rejected.
In particular I demonstrate, in contrast with what Leifer suggests in an article published on the review Quanta in 2014, that modal interpretation is a ψ-epistemic model. I show as well that it is also ψ-dependent, so PBR theorem doesn’t invalidate this interpretation.
Referring to the title, modal interpretation says that quantum state is partly real and partly epistemic, and in the thesis I will explain in which sense. The total realism on the wavefunction prescribed by PBR theorem is on the contrary incompatible with a modal interpretation of it.
ABSTRACT The paper aims to bridge the history of quantum theory with its philosophical implications. The focus is not only on the scientific underpinnings of quantum mechanics (these theories emerged as ‘ad hoc’ responses to experimental anomalies) but also on the philosophical ramifications of its probabilistic nature and indeterminacy, which differ from classical realism. The paper examines Dirac's, Bell's, and modern views, focusing on how quantum mechanics (QM) challenges traditional notions of causality, objectivity, and truth while embracing epistemological and metaphysical perspectives. Debates over collapse theories and hidden variables are discussed, as well as Putnam's philosophical outlook, which includes his trenchant involvement with realism, logic, and the measurement problem. Finally, the paper proposes that QM represents a philosophical revolution that renews our understanding of reality, knowledge, and scientific explanation, rather than simply serving as a physical theory for assessing the prospects of quantum philosophy by connecting it to broader aspects such as relativity, causality, and scientific realism.
The author attempts to answer the questions there are in the title of this paper. These questions are questions that scientists and philosophers have been asking themselves for many decades since Quantum Mechanics was formulated to explain the phenomena of the atomic and subatomic world. First of all a short but complete historical review of the transition between Classical Mechanics and Quantum Mechanics there is. It is preceded by some of the methodological premises that fit a certain vision of science. Then the author examines the issues and debates that have occurred on aspects of quantum mechanics such as realism, non-locality and probabilism (in contrast to determinism of Classic Mechanics). In doing this author llustrates the foundations of the various interpretations of quantum mechanics which, in an attempt to resolve these problems, have been given. The absurdities, and conflicts with the common sense, of quantum mechanics are shown to be largely apparent. In doing this, we examine the analogies of classical physics, as well as those of everyday life. Recent experimental results are taken into consideration. It is concluded that Quantum Mechanics presents elements of rupture more with Classical Physics than with the everyday experience.