The history of physics is not only a sequence of experimental discoveries and observations, followed by their mathematical description; it is also a history of concepts. For an understanding of the phenomena, the first condition is the introduction of adequate concepts; only with the help of the correct concepts can we really know what has been observed. Heisenberg was born on December 5, 1901, in Wurzburg, Germany. His maternal grandfather was the headmaster of the prestigious Maximilian Gymnasium in Munich, and his father, a scholar of ancient Greek philology and modern Greek literature. Heisenberg’s carrier however is regarded as being somewhat controversial due to debate over his activities during World War II. In Heisenberg’s first major paper on quantum theory, he resolved to get rid of any consideration of electron orbits. A cloud chamber is a very simple device for studying particles. They were first used, highly successfully, in the detection of cosmic rays.
The history of physics is not only a sequence of experimental discoveries and observations, followed by their mathematical description; it is also a history of concepts. For an understanding of the phenomena, the first condition is the introduction of adequate concepts; only with the help of the correct concepts can we really know what has been observed. Heisenberg was born on December 5, 1901, in Wurzburg, Germany. His maternal grandfather was the headmaster of the prestigious Maximilian Gymnasium in Munich, and his father, a scholar of ancient Greek philology and modern Greek literature. Heisenberg’s carrier however is regarded as being somewhat controversial due to debate over his activities during World War II. In Heisenberg’s first major paper on quantum theory, he resolved to get rid of any consideration of electron orbits. A cloud chamber is a very simple device for studying particles. They were first used, highly successfully, in the detection of cosmic rays.
Werner Heisenberg, co-discoverer of quantum mechanics, was born on December 5, 1901, in Würzburg, Germany, the second son in a scholarly family. His father, August Heisenberg, initially taught at a gymnasium but after his Habilitation was appointed Professor of Greek Philology at the University of Munich in 1911. Werner’s teachers in Munich made observations about the 10-year-old which seem prescient today (but which probably characterize bright children everywhere): “He has an eye for what is essential and never gets lost in details…great interest and thoroughness, and ambition.” Heisenberg excelled over the other boys at skiing and chess. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Abstract There is a certain similarity in the early lives of Planck and of Heisenberg [1,2]. Both had fathers who were professors at the University of Munich, both visited the Maximilians-Gymnasium in Munich, and both went to see a professor in Munich to seek advice for their studies. We have mentioned at the beginning of the Prologue how Jolly in vain tried to dissuade Planck from studying physics. Heisenberg, in his autobiographic book [3], which is devised as a series of conversations, tells us of a similar experience. In the autumn of 1920, when he was about to enter the university, his first choice was mathematics. He wanted not only to do course work but also learn about problems of current interest. This, he thought, he could do best by participating in a professor’s seminar usually reserved to advanced students and Ph.D. candidates. He asked for an interview with Lindemann , the most distinguished mathematician in Munich, who was famous for having proved that the number π is transcendental. But the old professor and the young student found no understanding, partly because Lindemann’s dog noisily interfered. The result was that Heisenberg opted for theoretical physics and went to ask Sommerfeld to be admitted to his seminar. Sommerfeld agreed. At that time Pauli, only a year older than Heisenberg, was already actively doing research under Sommerfeld. The two young men became life-long friends.
Abstract Erwin Schrödinger was born on 12 August 1887 in Vienna. His father was a Viennese and came from a very cultured family. The ancestors of his mother came from England which explains why Schrodinger spoke and wrote a practically flawless English. The relationship between father and son was excellent. To the growing boy the father was friend and teacher and he never tired of answering the inquisitive questions which the bright and interested boy produced in plenty. His elementary education was private and was carried out at home. At the age of 11 he entered the Akademische Gymnasium, a first-class grammar school which emphasized classical education, Latin and Greek. In spite of his main interest in mathematics and physics he loved the old languages as well as classical German and foreign poetry, and he was an addict of the famous Burgtheater in Vienna. He entered the University of Vienna in 1906. His great and beloved teacher there was F. Hasenohrl who had just succeeded to the chair of Boltzmann and who considered it his privilege and duty to continue the work of this great theoretical physicist. Hasenohrl was a very gifted physicist indeed and probably he would have been capable of great achievements had he not been killed in 1916 serving at the Italian front. He exercised a profound and lasting influence on the student Schrodinger. When much later Schrodinger received the Nobel Prize he said: ‘had Hasenohrl not been killed so young he would now be here in my place.’ Schrodinger himself served during the war as an artillery officer in Italy. From 1910 onwards his first publications began to appear. They were concerned with statistical problems, dielectrics, magnetism, and so on. Later on he also worked on X-ray diffraction in lattices, following the great discovery of von Laue in 1912.
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.
Heisenberg in Göttingen, Copenhagen and Helgoland Werner Heisenberg studied under Sommerfeld in Munich and was present at the Bohr Festspiele held in Göttingen in 1922 (Sect. 8.2). Although aged only 20, he challenged Bohr's support of Kramers' analysis of the quadratic Stark effect, having studied the paper in detail for Sommerfeld's seminar in Munich. The result was a long walk with Bohr during which they discussed this topic and the more general problems of quantum physics. This encounter made a strong impression on Heisenberg. Much later Heisenberg stated: ‘That discussion, which took us back and forth over Hainberg's wooded heights, was the first thorough discussion I can remember on the fundamental physical and philosophical problems of modern atomic theory, and it has certainly had a decisive influence on my later career. For the first time, I understood that Bohr's view of his theory was much more sceptical than that of many other physicists – for example, Sommerfeld – at that time, and that his insight into the structure of the theory was not a result of mathematical analysis of the basic assumptions, but rather of an intense occupation with the actual phenomena, such that it was possible for him to sense the relationships intuitively rather than derive them formally.’ Heisenberg spent the winter of 1922–1923 working in Göttingen as Born's assistant. The astronomers had made great progress in the use of perturbations techniques within the action–angle formulation of classical dynamics to study the gravitational perturbations of planetary orbits.
Erwin Schrödinger, co-discoverer of quantum mechanics, was born to middle-class, intellectual parents in Vienna in 1887. His father, who owned a linoleum factory, was an enthusiastic amateur botanist. His grandfather on his mother’s side was a chemist and professor at the Polytechnicum (the technical university) in Vienna. Erwin, an only child surrounded by adoring adult women (mostly maiden aunts), had a happy upbringing. He showed early talent at mathematics and was the most promising pupil at his Gymnasium. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.