Werner Heisenberg (1901–1976) is, in the textbook, the man of the uncertainty principle, the founder of matrix mechanics and – as the youngest representative of the first quantum generation alongside Bohr, Born, Pauli and Dirac – one of the intellectual architects of modern physics. What does somewhat appear in the textbook but rarely in full depth: Heisenberg developed over almost five decades a worked-out metaphysical reading of physics, at the centre of which stands the concept of the central order – a fundamental layer of reality conceived as the common source of physical law, mathematical form and ethical-aesthetic truth. His autobiographical main work Physics and Beyond / Der Teil und das Ganze (Piper 1969) and the later collections Schritte über Grenzen (1971) and Tradition in der Wissenschaft (1977, posthumous) condense this programme in a language that explicitly refers to Plato, Bacon, Eckhart and the Christian-philosophical tradition. Heisenberg is in our series the case in which the metaphysical half has remained most visible – and in which the reach of this half is nonetheless consistently played down as the "late philosophy of a physicist".
Who was Heisenberg?
Born on 5 December 1901 in Würzburg, son of the classical philologist August Heisenberg, who a few years later became Professor of Medieval and Modern Greek philology at the University of Munich. Heisenberg's intellectual atmosphere was from the start twofold: on the one hand the strict Munich mathematical school (Sommerfeld), on the other the humanist-Hellenist parental home. Heisenberg stressed several times in his memoirs that the reading of Plato's Timaeus on a Munich rooftop in 1919 – aged 17, under the impression of the Bavarian Soviet Republic – was a formative experience. This duality (mathematical rigour plus Platonic vision) runs through his entire work.
Doctorate under Arnold Sommerfeld in Munich 1923, habilitation under Max Born in Göttingen 1924, Privatdozent with Bohr in Copenhagen 1924–1927. From 1927, aged 25, full professor in Leipzig – the youngest German appointment of this kind. 1932 Nobel Prize in Physics. From 1942 Director of the Kaiser Wilhelm Institute for Physics in Berlin, from 1946 (after the renaming to Max Planck Institute and the move to Göttingen) until 1958 the same, then from 1958 Director of the MPI for Physics and Astrophysics in Munich until his retirement in 1970. Heisenberg died on 1 February 1976 in Munich.
Helgoland 1925: the breakthrough to matrix mechanics
In early summer 1925, suffering from severe hay fever, Heisenberg retreated to the North Sea island of Helgoland. Within a few weeks the matrix mechanics arose there – the first mathematically closed formulation of quantum mechanics. Heisenberg later described the breakthrough in Der Teil und das Ganze in an almost literary scene: he had stood at night on a cliff and felt that "through the outside of the atomic phenomena a ground of a peculiar inner beauty came to the fore (…) and I was almost dizzy at the thought that I should now work out this wealth of mathematical structures that nature had spread before me there." The mystic-aesthetic colouring of the self-narration is programmatic: for Heisenberg the mathematical structure was not a tool you impose on nature but an order found, that is seen.
1927 the uncertainty principle Δx · Δp ≥ ℏ/2 – that central statement of quantum mechanics, that position and momentum of a particle cannot be determined simultaneously with arbitrary precision. The uncertainty principle has both epistemological and ontological readings; Heisenberg's own position remained ontological throughout his life: the uncertainty is not a deficit of our measurement but a property of reality itself.
The war years – a necessary note
Heisenberg remained in Germany during the Nazi period, took over in 1942 the scientific leadership of the Uranverein (the German atomic project) and was for that interned for six months by the British Allies at Farm Hall. The later released Farm Hall Transcripts are the most important source on his actual knowledge about the bomb. His visit to Bohr in Copenhagen in 1941 is, since the publication of Bohr's unsent letters in 2002, better documented but still disputed in interpretation (Michael Frayn's 1998 play Copenhagen has kept the question in the public eye). This is not the subject of this article, but it belongs to the biography and is explicitly mentioned: Heisenberg's philosophical work cannot be read without this historical context.
The Platonic premise
Heisenberg's central philosophical thesis has been consistent since the 1930s and publicly worked out since the late 1950s: The fundamental building blocks of matter are not "smallest particles" but mathematical forms. He explicitly invokes Plato's dialogue Timaeus, in which the elementary building blocks are thought as geometrical bodies (regular polyhedra). Heisenberg reads modern quantum field theory – particularly his own late "world formula" of 1958, the nonlinear unified field theory – as historical confirmation of this Platonic basic intuition. In his lecture Schritte über Grenzen (1971) and in the essay Die Plancksche Entdeckung und die philosophischen Grundfragen der Atomlehre (1958) he says explicitly: the elementary particles of our physics are forms in the sense in which Plato spoke of forms.
This Platonic reading is not a late development. It is the precondition. Heisenberg portrayed in Der Teil und das Ganze that already in 1919 – in the Munich Bavarian-Soviet-Republic summer – the reading of the Timaeus had co-motivated his decision for theoretical physics. Whoever learns only the uncertainty principle from him does not have the starting point of the whole construction.
Physics and Philosophy (1958): the Gifford Lectures
In 1955/56 Heisenberg delivered at the Scottish University of St Andrews the Gifford Lectures – the same tradition in which before him William James, Henri Bergson, Alfred North Whitehead, Niels Bohr and after him John Eccles spoke. The lectures appeared in 1958 from Harper under the title Physics and Philosophy. The Revolution in Modern Science, in German 1959 as Physik und Philosophie from Hirzel. The book is the most compact available presentation of Heisenberg's philosophical position.
The central theses:
- Classical materialism – "the world consists of little pieces of matter in space and time" – is definitively refuted by quantum mechanics. The world does not consist of such pieces, neither conceptually nor experimentally.
- What takes the place of matter are mathematical structures, which manifest themselves in observational contexts in various, mutually complementary ways.
- The ontological status of the elementary particles corresponds not to Aristotelian matter but to Platonic form. Heisenberg says this in so many words.
- The language of classical physics is inadequate for the quantum level. We need a new conceptual apparatus, which must be co-fed by older ontological traditions, including ancient philosophy and the religious languages.
Physics and Beyond (1969): the central order
In 1969 Heisenberg published with Piper-Verlag Munich his autobiographical-philosophical main work: Der Teil und das Ganze. Gespräche im Umkreis der Atomphysik (English: Physics and Beyond, Harper 1971). It is a literary reconstruction of twenty central conversations Heisenberg had conducted with Bohr, Pauli, Einstein, Dirac, Schrödinger and others over the course of his life – each at the level of the contemporary physical question. The book is not a memoir in the usual sense; it is a philosophical argument in dialogue form, in the Platonic tradition.
The most famous chapter is Chapter 17, Diskussionen über die Beziehung zwischen Naturwissenschaft und Religion. Heisenberg reconstructs here a nocturnal discussion in Brussels during the 1927 Solvay Conference among himself, Wolfgang Pauli and Paul Dirac. Dirac represents in it strict naturalism ("religion is a collection of superstitions"); Pauli – ironic, witty, in form, but methodologically precise – defends the structural necessity of a religious language to designate what natural science must methodologically bracket out. Heisenberg himself enters as the third speaker and introduces the concept that will carry the rest of his work: the central order of things.
"If we now discuss for a moment what we should call by the name of ‘God', then we can (…) come at any rate to the view that the central order of which one speaks here has in any event an effective share in the world and that man cannot simply escape from it."
— W. Heisenberg, Der Teil und das Ganze, Piper, Munich 1969, ch. 17 (own translation).
The central order is not an additional object set apart from the physical structures. It is – on Heisenberg's conception – that level of reality from which the mathematical laws of nature emerge as do the ethical and aesthetic standards. Heisenberg uses the word God sparingly and cautiously, because he does not want to prejudge the theological connotations; but he says several times explicitly that what religious language designates as "God" corresponds in his methodological reading to the central order. It is not the "first mover" of Aristotelian natural philosophy but rather the Platonic idea of the Good – the source in which being and knowing, matter and form come together.
The Bacon bonmot
Several Heisenberg texts cite a bonmot that he explicitly attributes to Francis Bacon, but which is later also attributed to Heisenberg himself (in popular collections sometimes erroneously):
"The first sip from the cup of natural science makes you atheistic; but at the bottom of the cup, God awaits."
— Heisenberg, Der Teil und das Ganze, ch. 17, paraphrasing Francis Bacon, Of Atheism (1601): "A little philosophy inclineth man's mind to atheism, but depth in philosophy bringeth men's minds about to religion."
Heisenberg uses the saying as a self-characterisation of his scientific development: the first successes of modern physics – quantum mechanics, the uncertainty principle – suggested a disenchanted, "atheistically" formulable world. But the deeper reading of the same theories – complementarity, the observer problem, the Platonic form-reading of elementary particles – leads, on Heisenberg's account, precisely the other way around, back to an open metaphysical question that is better articulated in the religious language of tradition than in the reductionist language of the 19th century.
Ordnung der Wirklichkeit (written 1942, posthumous 1989)
A special position is held by a manuscript that Heisenberg wrote in 1942, in the worst phase of World War II, for his family: Ordnung der Wirklichkeit (Order of Reality). Heisenberg put the work in his desk drawer. Only in 1989, thirteen years after his death, was it published by Piper. The manuscript outlines a complete layered theory of reality: physical-inorganic layer, biological layer, psychic-mental layer, spiritual-religious layer – each layer is its own legitimate level of description, none is reducible to another.
This layered theory is very similar to the later three-world ontology of Karl Popper and John Eccles in The Self and Its Brain (1977), but appears three decades earlier. Heisenberg never published the manuscript himself; the family only released it after his death. With that Ordnung der Wirklichkeit exemplarily documents the pattern of our series: a metaphysical main document by a top physicist that he did not want to make public during his lifetime – probably out of institutional caution.
Pauli – the lasting conversation partner
Heisenberg's metaphysical line cannot be thought without Wolfgang Pauli. Heisenberg and Pauli had known each other since the Munich doctorate in 1923 and remained correspondents for over forty years. The Heisenberg-Pauli letters (critically edited by Karl von Meyenn, three volumes 1979–2005) are one of the most important source corpora for the history of quantum mechanics and for its metaphysical underlying layer. Pauli is also the one who brings the word central order from the Bacon context into the 1927 Brussels discussion – Heisenberg takes it over from him.
Heisenberg and Pauli developed differently in their positions: Pauli to Jungian depth psychology and the unus-mundus concept (jointly with Jung 1952), Heisenberg to the Platonic reading and the layered theory. But they shared the same investigation space for decades. Reading Heisenberg without Pauli – or vice versa – misses the historical situation.
Hans-Peter Dürr – the successor
Heisenberg's closest collaborator and eventual successor as executive director of the MPI in Munich was Hans-Peter Dürr (1929–2014). In the last two decades of his life Dürr publicly continued the metaphysical Heisenberg line more explicitly than Heisenberg himself had done. His late books (Crotona, Herder) and his popular lectures under the slogan "There is no matter!" are a continuation of Heisenberg's Platonic reading of elementary particles into a language addressed to broader publics. Heisenberg's metaphysical programme thus has a generational line reaching into the 21st century.
Position in the pattern
Heisenberg differs from the other post-1906 cases of our series in one important respect: his philosophical writings are not omitted from the standard Heisenberg image but classified. In most histories of physics Der Teil und das Ganze appears as a known work; in university seminars on philosophy of science it is regularly read; the Bacon bonmot is known to every physicist. To that extent Heisenberg is in the row of the "less suppressed" cases.
The marginalisation occurs more subtly – through downplaying the reach:
- The Platonic form-reading of the elementary particles, an ontological main thesis, is often treated as a "rhetorical figure" or "Pythagorean reminiscence" – not as serious ontology.
- The concept of the central order is treated as a "literary metaphor" – not as a methodological proposal to name a really effective layer of reality.
- The layered theory of Ordnung der Wirklichkeit (1942/1989) is treated as a "theological private work" – not as a systematic answer to the question how different descriptive levels relate to one another.
- Heisenberg's explicit religious language is interpreted as "cultural politeness" toward tradition – not as a statement about reality.
With this Heisenberg is our exemplary case for the third marginalisation variant (after "deleted from the textbook" as with Maxwell and "editorially separated reception" as with Schrödinger): downplaying the reach. The texts are there, they are cited, they are taken into anthologies – but their actual force is systematically dimmed in popular and academic reception. Anyone who wants to read the undimmed Heisenberg has to take Der Teil und das Ganze, Schritte über Grenzen and Ordnung der Wirklichkeit in hand themselves.
What remains
- Platonic reading of quantum mechanics. Heisenberg's thesis that the fundamental building blocks are forms, not particles, is the ontological consequence he reaches from his own physics. It is not refuted from the textbook; it is rarely spelt out from the textbook.
- Central order. Heisenberg's concept names the common source of physical, ethical and aesthetic truth. It is unusual for a top 20th-century physicist and belongs in the same conceptual family as Pauli's unus mundus, Schrödinger's singular consciousness and Bohm's implicate order.
- Ordnung der Wirklichkeit. The 1942 manuscript, first published in 1989, is Heisenberg's most systematic metaphysical writing. It deserves a reading of its own, independently of Der Teil und das Ganze.
- Bacon bonmot. "The first sip makes atheistic; at the bottom of the cup, God awaits." Heisenberg uses the saying literally as a self-characterisation of his own scientific development. It is not ornamental coquetry but programme.
- Position in the pattern series. Heisenberg is the "less suppressed" case – but not "not suppressed". The marginalisation occurs through downplaying instead of through omission. He thus rounds out the series with a third variant alongside "textbook gap" (Maxwell, Kelvin) and "editorial separation" (Schrödinger, Bohm, Eccles). For the institutional background see our article on Mediumship and Power.
Including Heisenberg does not mean judging the uncertainty principle or matrix mechanics differently. It means reading them in the metaphysical framework in which their originator embedded them – a framework in which the fundamental structures of matter are understood as Platonic forms and in which the laws of physics emerge from a common central order with the laws of ethics and aesthetics. Whoever brings this underlying layer back into the reading reads the historical Heisenberg – a physicist who was seriously concerned with the restoration of the Platonic heritage in modern natural science and who said so in a form whose visibility the textbook of the 20th and 21st century dims, without erasing it.
Sources
- Werner Heisenberg: Der Teil und das Ganze. Gespräche im Umkreis der Atomphysik. Piper, Munich 1969 (numerous editions; standard edition of the autobiographical-philosophical main work). English: Physics and Beyond. Encounters and Conversations, Harper, New York 1971.
- Werner Heisenberg: Physics and Philosophy. The Revolution in Modern Science. Harper, New York 1958 – the Gifford Lectures of 1955/56 at St Andrews. German: Physik und Philosophie, Hirzel, Stuttgart 1959.
- Werner Heisenberg: Schritte über Grenzen. Gesammelte Reden und Aufsätze. Piper, Munich 1971 (expanded edition 1973).
- Werner Heisenberg: Tradition in der Wissenschaft. Reden und Aufsätze. Piper, Munich 1977 (posthumous).
- Werner Heisenberg: Quantentheorie und Philosophie. Vorlesungen und Aufsätze. Ed. Jürgen Busche, Reclam, Stuttgart 1979 (posthumous).
- Werner Heisenberg: Ordnung der Wirklichkeit. Piper, Munich 1989 (manuscript 1942, posthumous).
- Karl von Meyenn (ed.): Wolfgang Pauli. Wissenschaftlicher Briefwechsel mit Bohr, Einstein, Heisenberg u. a.. 4 vols., Springer, Berlin 1979–2005 – critical complete edition.
- David C. Cassidy: Uncertainty. The Life and Science of Werner Heisenberg. W. H. Freeman, New York 1992 – the standard history-of-science biography.
- Carl Friedrich von Weizsäcker: Aufbau der Physik. Hanser, Munich 1985 – philosophical main work by his closest student, with many Heisenberg discussions.
- Werner Heisenberg: Gesammelte Werke / Collected Works. Ed. W. Blum, H.-P. Dürr, H. Rechenberg, Piper / Springer 1984ff.
- Operation Epsilon: The Farm Hall Transcripts. Ed. Charles Frank, University of California Press 1993 – the released transcripts of the 1945 internment.