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.
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 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 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.
In PHYSICS AND PHILOSOPHY: The Revolution Modern Science, (1) Werner Heisenberg aims, in not too technical language, to clarify change concept of reality manifesting itself quantum theory. He means to contribute to an articulation of the (not only epistemology) that underlies quantum theory's modified logical patterns. (2) To highly unusual degree, Heisenberg is gripped by sense of responsibility of modern quantum physicist to convey, language immediately intelligible to thinking public, his most serious and far-reaching reflections on metaphysical implications of his scientific work. One may go so far as to say that there is substantial evidence, partly within Physics and Philosophy, that Heisenberg regards such reflections and their public communication as his most important task. Heisenberg is especially apt for this intensely self-conscious contribution to humanity's historical-cultural development because his stature as principal originating architect of quantum at its most fundamental level is complemented by his deployment of an unusually broad and deep erudition and lifelong preoccupation with philosophic and artistic ontology from Anaximander through Kant and Goethe to Heidegger. No thinker has yet appeared who possesses such an authoritative combination of decisively necessary learning quantum physics and historical development of philosophic ontology. Despite flurry of renewed scholarly interest development of Heisenberg's scientific work, (3) and his complex relation to dramatic unfolding of German cultural his time, (4) there has yet to be executed sustained and philosophically critical interpretative commentary on this book that is his crucial philosophical-ontological legacy. Given profound ontological puzzles that continue to attend quantum physics and its implications for humanity's past as well as present and future conception of reality, such critical exegesis of this text is overdue. In what follows I try to extricate central nerve of Heisenberg's sinuously unfolding, dialectical exposition, and process to elucidate its strengths but also its deep ambiguities and perplexities--which express, I believe, fundamental dilemmas that pervade contemporary ontology. I Heisenberg makes inviolability of principle of noncontradiction cornerstone of his discussion. Unlike Aristotle (5) Heisenberg does not wrestle with challenge posed by possible denial of principle. He understands nonmathematical articulation of quantum to escape what would otherwise be devastating contradictions--most obviously contradiction wave/particle character of basic entities described by theory--through Bohr's famous principle of complementarity (which Heisenberg closely associates with von Weizsacker's notion of coexistent states), combined with Heisenberg's own principle of potentia, potentiality, potentialities. (6) II After brief introduction, Heisenberg his second chapter sketches history of quantum theory and process begins to explain what he means by potentia. In 1924 Bohr and his colleagues tried to solve apparent contradiction between picture and particle picture by concept of wave. The electromagnetic were treated not as 'real' waves but as mathematical descriptions of probabilities, every point relevant space, for the absorption (or induced emission) of light quantum by an atom at this point. Later this idea of was applied more effectively to much more abstract mathematical in many-dimensional configuration space that was discovered through researches of Schrodinger. Heisenberg reinterprets this mathematical probability wave ontological tenus, as signaling tendency [Tendenz] for a definite happening [einem bestimmten Geschehen], thus introducing remarkable kind of physical reality, standing middle between possibility and actuality: a quantitative version of old concept of 'dunamis' or 'potentia' philosophy of Aristotle. …
Abstract When Werner Heisenberg presented his views of the fundamental indeterminism to which his uncertainty principle pointed in the basic levels of reality described by quantum mechanics, he used the Aristotelian technical terms of act and potency, affirming that the quantum system is in potency before the measurement and that the potency was actualised when the measurement took place, speaking thus of a ‘new ontology’ of quantum mechanics. I argue that Thomas Aquinas’ Aristotelian account of indeterminism in nature, through his analysis of the notions of matter as potency and form as act, can provide a suitable framework to understand Heisenberg's philosophical intuition about the nature of quantum systems.
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.
Some considerations are presented on the so called “ontological interpretations” of quantum physics, starting from a remark by Werner Heisenberg on the relation between the probabilistic character of quantum states and the Aristotelian notion of “potency”. We show how an interesting revival of the original idea by Heisenberg can be found in the recent scientific and epistemological literature, in order to solve some paradoxical aspects emerging within some of the usual interpretations of quantum physics. Moreover a way seems to be open in order to rediscover the role of Aristotelian-Thomistic notion of “analogy” of “causal agents” operating even in the physical world. The “Potency-Act” interpretation of quantum physics appears aside the role of the Aristotelian notion of “Form” when it is compared with the recent notion of “information” in the context of the physics of “complex systems” and the biology of “living systems”.