Karl Popper and Paul Feyerabend were among the most influential philosophers of science of the twentieth century. Extensive studies have been dedicated to the development of their controversial relationship, which saw Feyerabend turning from a student and supporter of Popper to one of his harshest critics. Yet, it is not as well known that the rift between Popper and Feyerabend arose mainly in the context of their studies on the foundations of quantum mechanics, which has been the main subject of their discussions for about two decades. This paper reconstructs in detail their diatribe over the foundations of quantum mechanics, emphasising also the major role that their personal relationship played in their distancing.
Karl Popper and Paul Feyerabend were among the most influential philosophers of science of the twentieth century. Extensive studies have been dedicated to the development of their controversial relationship, which saw Feyerabend turning from a student and supporter of Popper to one of his harshest critics. Yet, it is not as well known that the rift between Popper and Feyerabend arose mainly in the context of their studies on the foundations of quantum mechanics, which has been the main subject of their discussions for about two decades. This paper reconstructs in detail their diatribe over the foundations of quantum mechanics, emphasising also the major role that their personal relationship played in their distancing.
This collection of the writings of Paul Feyerabend is focused on his philosophy of quantum physics, the hotbed of the key issues of his most debated ideas. Written between 1948 and 1970, these writings come from his first and most productive period. These early works are important for two main reasons. First, they document Feyerabend's deep concern with the philosophical implications of quantum physics and its interpretations. These ideas were paid less attention in the following two decades. Second, the writings provide the crucial background for Feyerabend's critiques of Karl Popper and Thomas Kuhn. Although rarely considered by scholars, Feyerabend's early work culminated in the first version of Against Method. These writings guided him on all the key issues of his most well-known and debated theses, such as the incommensurability thesis, the principles of proliferation and tenacity, and his particular version of relativism, and more specifically on quantum mechanics.
We scan Paul K. Feyerabend's work in philosophy of physics and of science more generally for insights that could be useful for the contemporary debate on the foundations of quantum mechanics. We take as our starting point what Feyerabend has actually written about quantum mechanics, but we extend our analysis to his general views on realism, objectivity, pluralism, and the relation between physics and philosophy, finding that these more general views could in fact offer many interesting insights for physicists and philosophers working on quantum foundations.
In this article I will focus on the debate on the causality principle that originated in the light of quantum mechanics concerning Moritz Schlick and Karl Popper. The discovery of quantum mechanics led to a broad debate on the interpretation of the principle of causality. Schlick proposed that it should be understood as an empirically verifiable postulate, and therefore with limits regarding causal indeterminacy in quantum physics. This approach had an influence on some scientists, especially Werner Heisenberg. However, Popper would develop a different way of understanding science because of the role played by unverifiable elements in theories that can nevertheless be falsified. It is precisely the discussion around the principle of causality that opens up different ways of understanding science. I will first try to analyse Schlick’s argument in the context of the debate that was taking place in the late 1920s in the light of the new quantum mechanics; secondly, I will look at the reception that Schlick’s idea of causality had in Heisenberg and the Copenhagen Interpretation; thirdly, I will analyse Popper’s argument against Schlick’s interpretation; finally, I will try to see the resonances of this debate in Heisenberg and other physicists.
RESUMO: Este trabalho analisa idéias e atividades de Karl Popper referentes à controvérsia sobre interpretações e fundamentos da mecânica quântica. Atenção especial será dedicada às relações entre Popper e o físico italiano Franco Selleri, ao longo da década de 1980. A interpretação proposta por Popper para os enunciados probabilísticos como propensões, bem como seu ponto de vista realista, contribuíram para estabelecer uma ponte entre suas investigações filosóficas e a pesquisa física em mecânica quântica, ainda que sua idéia sobre as propensões tenha tido uma pequena repercussão entre físicos, matemáticos e filósofos. Argumentaremos neste trabalho que a influência de Popper na física foi possível devido à legitimação, a partir de 1970, da controvérsia sobre os fundamentos da teoria quântica como uma genuína controvérsia científica com implicações filosóficas. Popper foi beneficiado por essa legitimação, mas ele também contribuiu para fazer aquela controvérsia chegar a um público mais amplo que aquele dos físicos envolvidos na própria controvérsia. Palavras-chave: Popper, propensões, mecânica quântica, Selleri, ondas vazias. POPPER, PROBALITY AND QUANTUM MECHANICS Abstract: I intend to present in this paper Karl Popper’s ideas and activities concerning the controversy about the interpretations and foundations of quantum mechanics. I will pay special attention to Popper’s relationship with the Italian physicist Franco Selleri, during the 1980s. Popper’s ideas of propensity and realism contributed to build a bridge between his philosophy and physical research in quantum mechanics, even if his idea of propensity has had a weak reception among physicists, mathematicians and philosophers. I will argue that Popper’s contributions to physics were possible due to the legitimization in the 1970s of the controversy about the foundations of quantum mechanics, a process which permitted a trading zone between physics and philosophy. Popper was benefited by that process, but he also contributed to give to that controversy a larger audience than that of the physicists involved in that controversy. Keywords: Popper, propensities, quantum mechanics, Selleri, empty waves.
This essay offers a discussion and contextualisation of a series of letters exchanged between Jordi Cat and Paul Feyerabend from 1989 to 1994. These letters provide insights into Feyerabend’s later thought on a variety of themes including quantum holism, the disunity of science, the development of logical empiricism, and science activism. In doing so, we provide some original analysis and exegesis of Feyerabend’s evolving views on scientific methodology and quantum mechanics by focusing on Feyerabend’s changing attitudes towards Bohm, Bohr, and his eventual colleague Hans Primas and his later sympathies with the algebraic approach. We also highlight Feyerabend’s role in the growth of the Disunity of Science movement and how he connected disunity to practical considerations in the philosophy of action.
Bohr’s work in quantum mechanics posed a challenge to philosophers of science, who struggled with the question of whether and to what degree his theories and methods could be considered rational. This paper focuses on Popper, Feyerabend, Lakatos and Kuhn, all of whom recognized some irrational, dogmatic, paradoxical or even inconsistent features in Bohr’s work. Popper, Feyerabend, and Lakatos expressed strong criticism of Bohr’s approach to quantum physics, while Kuhn argued that such criticism was unlikely to be fruitful: progress in science is generally not made through philosophical reflection. Feyerabend’s criticism of Bohr gradually weakened, as he gained a more detailed understanding of the development of Bohr’s views on quantum mechanics, and this went together with an increasingly critical view of normative philosophy of science and was instrumental to his conversion to ‘anarchism’. This paper aims to show that quantum mechanics played a central role in their debates and disagreements on the rationality of science and the possibility of a normative philosophy of science.