Erwin Schrödinger (1887–1961) is in the physics textbook the man of the wave equation named after him, of the famous thought experiment with the cat and – somewhat less known – of the little book What is Life? (1944) with which molecular biology was born. What is not in the physics textbook: Schrödinger was for more than four decades a serious student of the Upanishads and of Advaita Vedanta philosophy, held individual consciousness to be an illusory multiplication of the one consciousness, and published this view openly in at least four books. The historically decisive point: he wrote the first part of his philosophical main work My View of the World in 1925 – a year before the discovery of wave mechanics. The Vedantic worldview was the precondition, not a later reflection. Anyone who knows Schrödinger's quantum mechanics from the textbook and not his Vedantic writings does not know the man who wrote the equation.
Who was Schrödinger?
Born on 12 August 1887 in Vienna, the only child of a botanist and oilcloth manufacturer. Studied at the University of Vienna from 1906, doctorate 1910 under Friedrich Hasenöhrl. From 1914 habilitation, war service as an artillery officer on the Italian front. After the war various positions: Jena, Stuttgart, Breslau, then in 1921 a chair in Zürich – that almost ten-year, mathematically and philosophically productive period out of which wave mechanics emerged.
In 1927 Schrödinger was called as successor to Max Planck to the most prestigious chair at the University of Berlin, and at the same time made a member of the Prussian Academy. In 1933 he left Berlin in protest against the National Socialists and moved, via Oxford (Magdalen College), back to Austria to the University of Graz (1936). After the Anschluss he fled again in 1938 – via Italy to Belgium and finally, at the invitation of Irish Prime Minister Éamon de Valera, to Dublin, where from 1940 he helped to build up the Dublin Institute for Advanced Studies and formed its intellectual centre for 17 years. In 1956 he returned to Vienna. He died on 4 January 1961 in Vienna of tuberculosis. Three daughters from three different relationships, formal marriage from 1920 to Annemarie "Anny" Bertel.
1933 Nobel Prize in Physics, jointly with Paul Dirac, "for the discovery of new productive forms of atomic theory" – that is, for wave mechanics (1926) and the Dirac equation (1928).
My View of the World – Part I, 1925
In autumn 1925, in the Engadine, Schrödinger wrote the first part of a philosophical manuscript that he called "Seek the way". It was explicitly not meant for publication – a personal account. Schrödinger left it in a drawer. He only took it out again in 1960, a year before his death, added a second part from his late years and brought out both texts under the title Meine Weltansicht (Zsolnay Verlag, Vienna 1961; English: My View of the World, Cambridge University Press 1964). We thus know exactly what Schrödinger was thinking in 1925 – from his own text, written down in that year.
The main thesis of this text is clearly Vedantic. Schrödinger argues: the individual consciousness which every "I" believes itself to have is not one among billions. It is the one consciousness which appears as "mine", "yours", "his" through the construction of the subject-object split. The subject-object split itself, for Schrödinger, is a methodological device of scientific cognition – not a property of reality. The same teaching that for two and a half thousand years has been formulated in the Indian Upanishads in the formula tat tvam asi ("That thou art").
Decisive chronologically: Schrödinger wrote these sentences in autumn 1925. In January 1926 he submitted the first of his six communications Quantisation as an Eigenvalue Problem to the Annalen der Physik. The wave-mechanical revolution came from a mind that had just seen through the subject-object split as a methodological convention.
The Schrödinger equation (1926) and wave mechanics
Between January and June 1926 Schrödinger published in four communications the wave mechanics named after him. The idea: quantum objects are described not by classical particle trajectories but by a time-dependent wave function ψ whose evolution follows the differential equation named after him. Shortly afterwards Schrödinger himself proved the mathematical equivalence of his wave mechanics with the matrix mechanics developed a year earlier by Heisenberg, Born and Jordan – since then both formulations are expressions of a single theory.
Schrödinger personally remained dissatisfied with the interpretation of the wave function all his life. Born had proposed in 1926 reading |ψ|² as probability density – Schrödinger rejected this reading. He would have preferred to see the wave function as a physically real oscillation. From this dissatisfaction the cat thought experiment grew in 1935.
Schrödinger's cat 1935 – an attack on the standard interpretation
In a paper for Die Naturwissenschaften (November 1935, "The present situation in quantum mechanics") Schrödinger proposed the famous thought experiment: a cat sits in a box with a radioactive sample. If an atom decays within an hour, a Geiger counter triggers a mechanism that releases prussic acid; the cat dies. Before opening the box, on the standard reading, the radioactive atom is in a superposition of "decayed" and "not decayed" – and consequently the cat is in a superposition of "dead" and "alive".
Schrödinger did not propose this image to tell a ghost story but to expose the standard reading as absurd. If you take the probability interpretation seriously for macroscopic objects, this is what you get. Later quantum-mechanics research has found two responses: decoherence theory (Zeh, Zurek, from the 1970s) explains the disappearance of superposition through interaction with the environment; the consciousness interpretation (von Neumann, Wigner) places the collapse in the observation by a conscious subject. For our series the more important point: Schrödinger's cat – as a physical argument – placed the question "what observes?" at the centre of quantum foundations, where it has stood unresolved ever since.
What is Life? (1944) – the birth of molecular biology
In February 1943 Schrödinger delivered in Dublin at the Royal Irish Academy three lectures on the question how life can be understood from physical principles. In 1944 the lectures appeared as a book at Cambridge University Press under the title What is Life? The Physical Aspect of the Living Cell. It is one of the most influential small books of the 20th century.
Schrödinger's main thesis: the hereditary material must be an aperiodic crystal – a highly ordered but non-periodic solid whose atomic arrangement encodes the hereditary information. Watson and Crick have each said later that this book inspired them as young researchers to take up the question of the substance of heredity. Maurice Wilkins has also cited it. The DNA double helix in 1953 was, in a direct intellectual thread, set in motion by What is Life?.
What is not mentioned in most biology textbooks today: the book ends with an epilogue "On Determinism and Free Will", in which Schrödinger argues explicitly in Vedantic terms. He notes that the individual consciousness does not follow from the material construction of the brain, but that the plurality of consciousnesses is an illusion:
"Consciousness is never experienced in the plural, only in the singular. (…) The plural number is only a metaphor, not really applicable. (…) Deus factus sum, I have become God. This sentence stood at the beginning of Vedantic philosophy and is also its final result."
— Erwin Schrödinger, What is Life?, Epilogue (1944).
This is not an appendix. It is the final statement of the book that inspired molecular biology. Anyone who reads What is Life? and stops before the epilogue has not finished the book.
Mind and Matter (1958)
In 1956 Schrödinger delivered at Trinity College, Cambridge, the Tarner Lectures under the title Mind and Matter. In 1958 they appeared at Cambridge University Press as a small book. Schrödinger develops the Vedantic argument here more broadly and systematically than in 1944. The central theses:
- Consciousness does not belong to the world of physics. It is not an additional object alongside atoms and fields; it is that in which the world of physics appears in the first place.
- The brain does not produce consciousness. It is a necessary but not sufficient condition for the one consciousness to constitute itself in a particular individual form as "this I".
- The plurality of consciousnesses ("mine", "yours", "his") is a construction of the subject-object split. Behind it stands one and the same consciousness.
- Natural science has built up, since the Greeks, a picture of an "objectified world" in which the subject does not appear. Precisely this methodological exclusion has generated the consciousness problem: it apparently does not appear in the world so constructed because it was already removed before.
"The over-all number of minds is just one. I venture to call it indestructible since it has a peculiar timetable, namely mind is always now. There is really no before and after for mind. There is only a now that includes memories and expectations."
— Erwin Schrödinger, Mind and Matter, ch. 4 (1958).
The Vedantic source: Upanishads and Schopenhauer
Schrödinger's Vedantic reading had two sources that reinforced each other. The immediately effective one was Arthur Schopenhauer, whose World as Will and Representation Schrödinger read already as a student and who himself drew explicitly on the – then newly available in European translation – Upanishads. The older source was the Upanishads themselves, which Schrödinger initially read in Paul Deussen's German translation and later in part also in the Sanskrit original (he learned Sanskrit in the 1920s sufficiently to check particular passages; he never became a fluent Sanskrit reader).
The central formula of the early Upanishads that Schrödinger cites again and again is tat tvam asi: "That thou art" – the identity of atman (individual self) and brahman (universal self). Schrödinger read this not as a religious confession but as an empirical philosophical observation: when I look attentively into the concept of "consciousness", I do not find a plural but a singular.
Walter Moore has reconstructed in detail in his standard history-of-science biography Schrödinger: Life and Thought (Cambridge University Press, 1989) how central this Vedantic line was for Schrödinger's entire life's work. It is not a hobby beside the physics but the underlying deep layer in which Schrödinger did physics at all.
Position in the pattern
Schrödinger is the first case in our series who lives and works after 1906 – and he shows a different variant of the pattern than the pre-1906 generation. Maxwell and Kelvin could deliver their theology publicly in official lectures. Schrödinger could still do so – What is Life?, Mind and Matter, My View of the World all appeared at Cambridge University Press or major Vienna publishers, with the Nobel-Prize imprimatur. But the reception has shifted: the texts are treated in the history of physics as "the philosophical writings" separated from the "actual work". There is a Schrödinger double-take: wave mechanics in the physics textbooks, Vedanta in the philosophical anthologies – and the two halves scarcely meet.
With this, Schrödinger is a bridge between two phases:
- Before him: Kepler, Boyle, Newton, Faraday, Maxwell, Kelvin – the theological/spiritual half is cut from the textbook but was originally public.
- With him and after him: Jung and Pauli develop a private correspondence language; Schrödinger continues to publish openly but is editorially received as two separate halves; Wigner makes the consciousness theme physically speakable again in 1961; Dürr and Josephson stand explicitly in this line.
The historical point – 1925, not 1944
If this series has a single exemplary finding, it is this: Schrödinger's Vedanta manifesto was complete in 1925, a year before wave mechanics. The popular narrative – a successful quantum physicist turns in old age to soft late topics – is historically false. It was the other way round. The Vedantic worldview was the precondition; the epochal physical breakthrough a year later was its expression. Anyone who wants to understand Schrödinger's quantum mechanics cannot bypass this chronology.
The same pattern is visible with Faraday (the theological assumption of the unity of creation stands before the experimental search for the unity of the forces) and with Maxwell (Presbyterian creation theology stands before the mathematical synthesis of electricity, magnetism and light). Physics is done on already-prepared philosophical-theological ground. The textbook acts as if it were the other way round.
What remains
- Schrödinger was not "also" a Vedantist. The Vedantic reading is the deep structure in which he formulated quantum mechanics. Leave it out and you get a different Schrödinger story, not the historical one.
- The "singular" statement is to be taken physically seriously. "The total number of minds in the universe is one" is not spiritual posturing but Schrödinger's reflected answer to the foundational question "Who observes the quantum collapse?", which has stood unresolved in the room since the cat in 1935. Wigner in 1961 picked up the same question in a different language.
- What is Life? has two halves. The aperiodic crystal founded molecular biology. The epilogue opened a second line – the one leading to Penrose, Hameroff and today's quantum-consciousness research. Both halves belong to the same book and the same argument.
- Bridge from the Pauli/Jung private sphere to the public.Jung and Pauli talk about synchronicity and unus mundus in a correspondence largely known only posthumously. Schrödinger publishes his variant of the same theme in the mainstream of Cambridge University Press – but the reception separates it from the "actual work". That is a different form of marginalisation than with Pauli (private) or with Lucadou (funding cut), but it leads to the same result: omitted from the public educational canon.
- Position in the pattern series. Schrödinger is the first wholly post-1906 case in our series. Kepler → Boyle → Newton → Faraday → Maxwell → Kelvin form the pre-1906 generation, each with editorially removed halves. Schrödinger together with Jung, Pauli, Wigner, Dürr and Josephson forms the post-1906 line, in which the spiritual half is still written but editorially received as separate from the "actual work". For the institutional background see our article on Mediumship and Power.
Including Schrödinger does not mean judging wave mechanics differently. It means reading it in the spirit in which its author wrote it down in 1926 – in the spirit of a man who had already noted in an Engadine summer-retreat manuscript half a year earlier that the individual I is a grammatical multiplication of the one consciousness. Bring this back into the reading and you read the historical Schrödinger – and at the same time you see that today's physics-consciousness question is not a modern embarrassment but that the quantum pioneer himself regarded it as his question.
Sources
- Walter Moore: Schrödinger: Life and Thought. Cambridge University Press 1989 – the standard history-of-science biography with extensive treatment of the Vedantic line.
- Erwin Schrödinger: My View of the World. Cambridge University Press 1964 (Part I: Engadine 1925; Part II: Alpbach/Vienna 1960). German original: Meine Weltansicht, Zsolnay, Vienna 1961.
- Erwin Schrödinger: What is Life? The Physical Aspect of the Living Cell. Cambridge University Press 1944 (Dublin lectures 1943).
- Erwin Schrödinger: Mind and Matter. Cambridge University Press 1958 (Tarner Lectures, Trinity College Cambridge 1956).
- Erwin Schrödinger: Nature and the Greeks. Cambridge University Press 1954 (Shearman Lectures, University College London 1948).
- Erwin Schrödinger: The present situation in quantum mechanics. Die Naturwissenschaften 23, 1935 (three parts) – with the cat.
- Erwin Schrödinger: Quantisation as an Eigenvalue Problem. Annalen der Physik (4), vol. 79, 1926 (four communications).
- Michel Bitbol & Olivier Darrigol (eds.): Erwin Schrödinger: Philosophy and the Birth of Quantum Mechanics. Editions Frontières, Gif-sur-Yvette 1992.
- Michel Bitbol: Schrödinger's Philosophy of Quantum Mechanics. Kluwer, Dordrecht 1996.
- Paul Deussen: Sechzig Upanischad's des Veda. Brockhaus, Leipzig 1897 – the German standard translation accessible to Schrödinger.