The discovery of quantum physics opened a broad debate on the epistemological status of the principle of causality. In this article, I analyze the problem of causality in Heisenberg by distinguishing two levels of philosophical explanation in his thought. As a philosopher of science, his understanding of causality is closely linked to Moritz Schlick, although he will later adopt a neo-Kantian view of the a priori. As a philosopher of nature, Heisenberg recovers the notion of potency to understand the wave function. My thesis is that this notion of potency could have allowed him to elaborate a realistic and nondeterministic theory of causality, but the identification of causality and determinism (in Schlick’s line) did not lead him to such a conclusion.
The discovery of quantum physics opened a broad debate on the epistemological status of the principle of causality. In this article, I analyze the problem of causality in Heisenberg by distinguishing two levels of philosophical explanation in his thought. As a philosopher of science, his understanding of causality is closely linked to Moritz Schlick, although he will later adopt a neo-Kantian view of the a priori. As a philosopher of nature, Heisenberg recovers the notion of potency to understand the wave function. My thesis is that this notion of potency could have allowed him to elaborate a realistic and nondeterministic theory of causality, but the identification of causality and determinism (in Schlick’s line) did not lead him to such a conclusion.
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.
In the present article we analyze the understanding and the use of the Kantian philosophy by the German physicist Werner Heisenberg, Nobel Prize of Physics of 1932, formulator of the principle of uncertainty. Heisenberg seems to adopt a neo-Kantian understanding of the nature of science, according to which science would not deal with the real itself, but only with the way it appears, which inescapably depends on the interaction between the subject and the object of knowledge. However, in spite of this conception, Heisenberg considers that the Kantian definitions of "space", "time" and "causality" are not compatible with the developments of the quantum mechanics. In this opportunity we will see more carefully the conception of science and the problem of causality.
The ideas in Heisenberg's paper on quantum mechanics in 1925 mark the beginning not only of a new phase in modern physics, but also of Heisenberg's own philosophical journey. This thesis examines that journey between 1925 and the late 1950s by situating Heisenberg's philosophy of quantum mechanics in the context of his encounters with his contemporaries as well as the context of various strands of thought in the German-speaking world at the time. Heisenberg's early philosophical critique of the 'classical' viewpoint between 1925 and 1927 bears the decisive influence of Einstein's theory of relativity, more specifically, the positivism he saw as underpinning Einstein's emancipation from Newtonian physics. The positivist influence on Heisenberg's early attitude to quantum mechanics is evident in three ways: (a) his invocation of an observability principle in 1925 to justify the renunciation of the concept of the electron orbit, (b) an instrumentalist conception of understanding, which characterised Heisenberg's response to Schrodinger's demand for classical visualisation in space and time in 1926-7, and (c) the introduction of an operational definition of concepts such as position and velocity in 1927, in an attempt to replace the concepts of classical physics. But after discussions with Bohr and Einstein in 1926-7, Heisenberg soon recognised what we might term his `empiricist' viewpoint was problematic. In 1927 Heisenberg's thought undergoes a shift away from the `empiricist' viewpoint that had underpinned his early philosophy of quantum mechanics. The nature and scope of this transformation, which forms the central theme in this thesis, has, up until now, been poorly understood and often completely neglected. Through his discussions with Bohr, Heisenberg came to the realisation that despite their limitations, classical concepts were conditions for the possibility of the description of all experience. This marked the abandonment of his earlier attempt to replace classical concepts with quantum concepts. The recognition of the primacy of classical language forms the point of departure for much of Heisenberg's later thought, which brought him into contact with the attempts in the German-speaking world in the 1920s to reconstruct Kantian epistemology. By the mid-1930s, Heisenberg advocated a 'pragmatic transformation' of Kantian philosophy, in which classical concepts were held to be a priori in the sense that they remained the conditions for the possibility of experience, but were no longer held to be necessary or universal in a strict Kantian sense. After 1940 Heisenberg saw the paradoxes of quantum mechanics under the aegis of what can be termed a 'transcendental conception of language', according to which language is not a mere tool, but actively shapes, gives form, and objectifies, our 'reality'. The limits of a classical 'description' in quantum mechanics therefore came to signify for Heisenberg, the limits of 'objective reality'. While Bohr exerted perhaps the most important philosophical influence on Heisenberg, their intellectual relationship was characterised by disagreement and misunderstanding. This is most strikingly displayed in their respective views on wave-particle duality and complementarily. While after 1927 Heisenberg accepted Bohr's basic insight that our knowledge of the quantum world is mediated through classical language, he did not share Rohr's interpretation of complementarity. While Heisenberg certainly used terms such as 'complementarity' and wave-particle duality' in his writings, a close reading reveals that these terms had very different meanings for the two physicists. This is particularly evident in the contrast between Heisenberg's notion of wave-particle equivalence and Bohr's idea of complementarity. In bringing to light these divergences between Bohr and Heisenberg, this thesis lends further weight to the view - already advocated by scholars such as John Hendry and Mara Beller - that the so-called Copenhagen interpretation of quantum mechanics should not be thought of as a unified philosophical position, but actually comprises a number of different strands.
Does the success of quantum mechanics require that we abandon the notion of complete scientific explanation? Or does it represent a breakthrough in the explanatory scope of physical theories? Ever since Werner Heisenberg formulated the theory of matrix mechanics in 1925, this issue has been the topic of a continuing philosophical debate. In this essay I propose to explain Heisenberg's rejection of the mechanistic philosophy associated with classical physics and the significance of his return to Aristotle's concept of matter as potency.
The article is devoted to the analysis of the concept of “reality” in the philosophical and scientific works of the theoretical physicist Werner Heisenberg. It analyzes the Heisenberg’s works on the philosophy of natural science, a significant part of which is devoted to quantum theory and its basic concepts. The author shows that Heisenberg’s thought was formed in parallel with the development of relevant problems among neo-Kantian philosophers (N. Hartmann, B. Nicolescu, etc.) throughout the 20th century. According to the author, many European researchers focus their attention on the scientific side of Heisenberg’s work, that is, on the analysis of his physical argumentation. The philosophical aspects of Heisenberg’s works are mostly studied by Russian philosophers of science. The intellectual vector of Heisenberg’s work was the idea of the need for a new philosophical thinking that goes beyond the scope of rational activity and requires a reconception of the gnoseological categories used as an instrument for the cognition of the reality. It relies on the phenomenological tradition, as well as on the arguments of J.W. von Goethe that theory cannot “capture” reality; it requires a synthesis of “trust in experience” and “intelligent observation” (discretion) to understand it. It is also demonstrated in the article the Heisenberg's attitude to the formation of the language of science and to the comparative studies of the philosophical systems of such thinkers as Plato, Democritus, Aristotle.
For Kant causality is an a priori category of the understanding, a necessary condition for the possibility of any experience. Later Wittgenstein’s philosophy rejects transcendentalism. We can only speak of causes and effects if in some basic situations, or ‘language games’, we already treat some things as causes of what happens. Since the notion of cause becomes meaningful only within a language game, it is not unambiguous. Quantum causal language games presuppose the use of quantum theory. We treat the latter as Wittgenstein’s grammar of a quantum form of life’, or rule (norm), anchored in its applications — quantum phenomena as language games. Quantum correlations are often interpreted as a manifestation of the nonlocality of quantum mechanics. This is a view of quantum phenomena from the perspective of classical physics. Our contextual point of view rejects the nonlocality of quantum theory in the sense of instantaneous causal influence at a distance. But it does not admit its locality in the sense of classical causality either. We introduce the notion of quantum causality which allows us to treat quantum correlations as local, but context-dependent. Their formal cause is an entangled wave function. Any particular quantum correlation, identifiable in a context of its observation as a result of the wave function reduction, post factum can be treated as a classical causal correlation. From the point of view of the proposed contextual quantum realism, epistemology is secondary, and ontology is sensitive to context. Quantum correlations exist (are real) before application of the theory, independently of their identification (description, measurement), but have no identity, which appears only as a result of application of the theory and their identification in the context. In other words, they are real, but not pre-determined, not autonomous.