2. Wochenendseminar zur Philosophie der Physik

Philosophie der Quantenmechanik

Bremen (Online), 18. – 20. Dezember 2020

Bild © Kaća Bradonjić

Der Workshop richtete sich insbesondere an Bachelor- und Masterstudierende der Physik und der Philosophie und hatte zum Ziel, mittels Fachvorträgen (von Vanessa Seifert (Bristol), Manfred Stöckler (Bremen), Marij van Strien (Wuppertal) und Stefan Wolf (Lugano)), einführender Vorlesungen (von Niels Linnemann, Kian Salimkhani und Norman Sieroka (Bremen)) und vertiefender Diskussionsgruppen (geleitet von Rasmus Jaksland (Trondheim), Lucy James (Bristol) und Tushar Menon (Cambridge)) das Forschungsgebiet der Philosophie der Physik vorzustellen. Schwerpunkt war diesmal die Philosophie der Quantenmechanik. Aufgrund der SARS-CoV-2-Pandemie fand das ursprünglich für Bremen geplante Wochenendseminar online statt.

Programm

Abstracts (nach Programmablauf geordnet)

Norman Sieroka (Bremen): Was ist Philosophie der Physik

Der Vortrag bietet eine systematische und allgemeinverständliche Einführung in philosophische Fragestellungen der Physik und ihre historische Entwicklung. Es werden kurz einige wichtige Stationen der Physikgeschichte in der Antike, der Frühen Neuzeit und den vergangenen zwei Jahrhunderten dargestellt, um an ihnen zentrale erkenntnistheoretische Merkmale der Physik aufzuzeigen; insbesondere typische Erklärungsstrategien, das Vorgehen bei der Begriffs- und Theoriebildung und die Bedeutung der Mathematik.

Manfred Stöckler (Bremen): Von der Physik zum Weltbild

Die Quantentheorie hat seit ihren Anfängen zu weitgehenden Spekulationen über ihre weltanschaulichen Folgerungen geführt. Im Zentrum standen zunächst die Willensfreiheit, die angeblich erst durch die Quantentheorie ermöglicht werde, und die neue Bedeutung des Bewusstseins in der Natur, die durch die Rolle des Beobachters im Messprozess impliziert schien. Die frühe Geschichte der Quantentheorie zeigt, dass Nüchternheit geboten ist, wenn man Erkenntnisse der Physik auf andere Gebiete ausweiten will. Im Vortrag wird es zunächst um einige Grundzüge der quantenmechanischen Beschreibung der Welt gehen (Unbestimmtheit, klassische und quantenmechanische Eigenschaftskonzeptionen, Messprozess, EPR-Paradoxon). Im nächsten Schritt wird an einigen Beispielen gezeigt, dass weitere philosophische Annahmen hinzukommen müssen, wenn man aus der neuen Physik philosophische (oder allgemein weltanschauliche) Konsequenzen ableiten will. Im Blick zurück werden die Schwierigkeiten dieses interdisziplinären Verständigungsprozesses sichtbar und auch die Fehler, die Physiker und Philosophen dabei gemacht haben. Seit den 60er Jahren haben VertreterInnen der angelsächsisch geprägten Wissenschaftsphilosophie die Debatten um die Interpretationen der Quantentheorie professionalisiert. Aber auch die Wissenschaftsphilosophie hat noch ihre Probleme mit ihrer Rolle als Mittlerin zwischen Physik und Weltbild.

Stefan Wolff (Lugano): Causality – Consistency – Complexity

Quantum theory predicts correlations that question fundamental space-time causality. Dropping the latter, while still maintaining logical consistency, has dramatic consequences for the power of communication and computation. Such reasoning is in the spirit of Landauer's famous slogan "Information is Physical." A variant of its paradigmatic rival, Wheeler's "It from Bit," is the Church-Turing hypothesis: All physical processes can be simulated on a universal Turing machine. We use the tension between the two viewpoints to look for a purely intrinsic randomness notion and find one around the second law of thermodynamics. Quantum correlations, combined with Kolmogorov complexity as randomness, reveal an all-or-nothing nature of the Church-Turing hypothesis: Either non-Turing computations are physically impossible, or they can be carried out by "devices" as simple as individual photons.

Marij van Strien (Wuppertal): The challenge of quantum mechanics to the limits of science, 1925–1936.

The modern theory of quantum mechanics, developed in 1925–26, has often been seen as a positivistic theory, because of the central role of observations and measurements in the theory and the dismissal of questions about what happens between measurements. At the same time, in the 1920s and 1930s, it was often concluded that quantum mechanics implies that there is a limit to what can be known scientifically, and this opened the door to a wide range of speculations, in which quantum mechanics was connected with free will, organic life, psychology and religion – connections which were drawn not in the least by quantum physicists themselves. This tension is perhaps nowhere stronger than in the work of Pascual Jordan, one of the leading quantum physicists of the period, who emphasized the positivistic elements in quantum mechanics as well as using it as the basis for an extravagant theory about the essence of organic life and the psychology of the will, a theory which, moreover, had National Socialist overtones. It is thus no wonder that Jordan’s theory was harshly criticized by the philosophers of science known as logical positivists, who argued for a scientific conception of the world based on logic and observation and avoiding all metaphysical speculation. But although Jordan’s claims could easily be dismissed, the resulting discussions (to which especially Moritz Schlick and Philipp Frank contributed) did reveal broader challenges posed by quantum theory: both Heisenberg’s uncertainty relations and Bohr’s notion of complementarity were often used to argue that there are fundamental limits to physical knowledge, and these possible limits to the scope and unity of science proved more challenging to deal with for defenders of the scientific world view.

Vanessa Seifert (Bristol) (joint work with Alex Franklin, King's College London): The Problem of Molecular Structure Just Is The Measurement Problem

Whether or not quantum physics can account for molecular structure is a matter of considerable controversy. Three of the problems raised in this regard are the problems of molecular structure. We argue that these problems are just special cases of the measurement problem of quantum mechanics: insofar as the measurement problem is solved, the problems of molecular structure are resolved as well. In addition, we explore one consequence of our argument: that claims about the reduction or emergence of molecular structure cannot be settled independently of the choice of a particular resolution to the measurement problem. Specifically, we consider how three standard putative solutions to the measurement problem inform our understanding of a molecule in isolation, as well as of chemistry’s relation to quantum physics.

Diskussionsgruppen

Vertiefungsliteratur (wird noch ergänzt)

Zur Geschichte der Quantenmechanik

(Besten Dank an Marij van Strien!)

On how in the 1920s and 1930s, quantum mechanics was connected to all kinds of big issues:

• Heilbron, J. L. (1985). The earliest missionaries of the Copenhagen spirit. Revue d’Histoire des Sciences, 38, 195-230.

On Jordan’s and Bohr’s application of quantum mechanics to biology and psychology:

• Beyler, R. H. (1996). Targeting the organism: The scientific and cultural context of Pascual Jordan's quantum biology, 1932-1947. Isis, 87(2), 248-273.
• Wise, M. N. (1994). Pascual Jordan: Quantum mechanics, psychology, national socialism. In Science, Technology, and National Socialism (ed. M Renneberg and M. Walker), 224-54. Cambridge: Cambridge University Press.
• Hoyningen-Huene, P. (1993). Niels Bohr’s Argument for the Irreducibility of Biology to Physics. In Niels Bohr and Contemporary Philosophy, ed. J. Faye and H. J. Folse, p. 231-255. Dordrecht: Kluwer Academic.

On quantum mechanics and the Vienna Circle:

• Faye, J. (2010). Niels Bohr and the Vienna circle. In The Vienna Circle in the Nordic Countries: Networks and Transformations of Logical Empiricism, ed. J. Manninen and F. Stadler, pp. 33-45. Springer, Dordrecht.

Zur Philosophie der Chemie

(Besten Dank an Vanessa Seifert!)

Aufsätze

• Woody, A. I. (2000). Putting quantum mechanics to work in chemistry: The power of diagrammatic representation. Philosophy of science, 67, S612-S627.
• Woolley, R. G. (1978). Must a molecule have a shape?. Journal of the american chemical society, 100(4), 1073-1078.
• Needham, P. (2010). Nagel's analysis of reduction: Comments in defense as well as critique. Studies in History and Philosophy of Science Part B: Studies In History and Philosophy of Modern Physics, 41(2), 163-170.
• Needham, P. (2004). When did atoms begin to do any explanatory work in chemistry?. International studies in the philosophy of science, 18(2-3), 199-219.
• Lombardi, O., & Labarca, M. (2005). The ontological autonomy of the chemical world. Foundations of Chemistry, 7(2), 125-148.
• Hettema, H. (2017). The union of chemistry and physics: linkages, reduction, theory nets and ontology (Vol. 7). Springer.
• Hendry, R. F. (2012). Reduction, emergence and physicalism. In Philosophy of chemistry (pp. 367-386). North-Holland.
• Hendry, R. F. (2006). Elements, compounds, and other chemical kinds. Philosophy of science, 73(5), 864-875.
• Primas, H. (2013). Chemistry, quantum mechanics and reductionism: perspectives in theoretical chemistry (Vol. 24). Springer Science & Business Media
• Scerri, E. (2019). The periodic table: its story and its significance. Oxford University Press.
• Chang, Hasok, 2012, Is Water H2O? Evidence, Realism and Pluralism (Boston Studies in the Philosophy of Science, Vol. 293), Dordrecht: Springer.
• Blumenthal, G., & Ladyman, J. (2018). Theory comparison and choice in chemistry, 1766–1791. Foundations of Chemistry, 20(3), 169-189.
• Blumenthal, G., & Ladyman, J. (2017). The development of problems within the phlogiston theories, 1766–1791. Foundations of Chemistry, 19(3), 241-280.

Recent collections of books:

• What Is A Chemical Element? A Collection of Essays by Chemists, Philosophers, Historians, and Educators, ed. Eric Scerri and Elena Ghibaudi, Oxford University press
• Baird, D., Scerri, E., & McIntyre, L. (Eds.). (2011). Philosophy of chemistry: Synthesis of a new discipline (Vol. 242). Springer Science & Business Media.
• Scerri, E. R., & Fisher, G. A. (Eds.). (2016). Essays in the Philosophy of Chemistry. Oxford University Press.

Internet sources:

• https://plato.stanford.edu/entries/chemistry/
• https://iep.utm.edu/red-chem/#SH5b
• https://www.jargonium.com (outreach blog on history and philosophy of chemistry)

Auswahl von Aufsätzen der Sprecher*innen

• Franklin, A., & Knox, E. (2018). Emergence without limits: The case of phonons. Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics, 64, 68-78.
• Franklin, A., & Seifert, V. A. (forthcoming). The Problem of Molecular Structure Just Is The Measurement Problem. The British Journal for the Philosophy of Science. http://philsci-archive.pitt.edu/18380/
• Seifert, V. A. (2020). The strong emergence of molecular structure. European Journal for Philosophy of Science, 10(3), 1-25.
• van Strien, M. (forthcoming). Ernest Nagel on Determinism as a Guiding Principle and its Compatibility with Quantum Mechanics. In M. Neuber and A. T. Tuboly (ed.), Ernest Nagel Between Naturalist Pragmatism and Logical Empiricism, Springer.
• van Strien, M. (2020). Bohm's Interpretation of Quantum Mechanics and the Notion of Classicality. Studies in History and Philosophy of Modern Physics 71 (2020), 72-86.
• van Strien, M. (2020). Pluralism and Anarchism in Quantum Physics: Paul Feyerabend’s Writings on Quantum Physics in Relation to his General Philosophy of Science. Studies in History and Philosophy of Science, 80, pp. 72-81.