# What Is Life? *By Erwin Schrödinger. Cambridge University Press, 1944. The book is a short write-up of three public lectures Schrödinger gave at Trinity College, Dublin, in February 1943, while he was running the School of Theoretical Physics at the Dublin Institute for Advanced Studies. It asks one question: "How can the events in space and time which take place within the spatial boundary of a living organism be accounted for by physics and chemistry?" His answer has three parts. Heredity must be carried by a very small, very stable molecule. That stability is a quantum-mechanical fact, the same one that holds a crystal together. And because this molecule is an "aperiodic crystal", it can hold a "code-script" for the whole organism. Living things also keep their order by "feeding on negative entropy", and they work by "order from order" rather than the "order from disorder" of ordinary statistical physics. The book ends with a short, personal Epilogue on free will that draws on the Upanishads. Watson and Crick both said it influenced them. Since 1967 Cambridge has sold it combined with Schrödinger's 1956 lectures* Mind and Matter*, and since 1992 also with his* Autobiographical Sketches *and a foreword by Roger Penrose. That combined volume is the edition in print today.* > **What I actually read.** I **read in full** the text of the 1944 *What Is Life?*: the Preface (dated "Dublin September 1944"), all seven chapters, the Note to chapter 6 and the Epilogue. My copy was an unofficial retyped and OCR'd text on the Internet Archive. It has OCR slips, it lacks the figures, and its internal page cross-references don't match any printing I could identify, so every quotation below was checked against the sense of the passage and lightly corrected for obvious OCR errors only. I am not linking that copy (see "Free (legal)"). Chapter titles and **page numbers** come from Cambridge Core's contents list for the Canto Classics edition (2012; viii + 184 pp.). The 1944 edition facts come from the National Library of Ireland catalogue (MARC) and Open Library/Internet Archive records. I **did not read** *Mind and Matter*, the *Autobiographical Sketches* or Penrose's foreword. What I say about them comes from their chapter titles, the publisher's description and secondary sources, and is marked as such. Related in this vault: the two source notes, [[Video Summaries/Curt Jaimungal/Roger Penrose My Crazy Idea That Explains the Universe]] and [[Video Summaries/Big Think/The laws of the universe are unable to explain these origin mysteries Paul Davies Full Interview]]; Penrose's [[Book Summaries/Penrose, Roger/The Emperor's New Mind - Roger Penrose|The Emperor's New Mind]] and [[Book Summaries/Penrose, Roger/Fashion, Faith, and Fantasy in the New Physics of the Universe - Roger Penrose|Fashion, Faith, and Fantasy in the New Physics of the Universe]], where Schrödinger's equation and his cat are central; and the author hub [[Book Summaries/Schrödinger, Erwin/Schrödinger, Erwin|Schrödinger, Erwin]]. ## 1. Book facts | | | |---|---| | Title | *What Is Life? The Physical Aspect of the Living Cell*. Title page: "Based on lectures delivered under the auspices of the Dublin Institute for Advanced Studies at Trinity College, Dublin, in February 1943". Dedication: "To the memory of my parents" | | Author | Erwin Schrödinger (1887–1961), Austrian theoretical physicist, Nobel Prize in Physics 1933 | | Edition verified | **First edition**, Cambridge [England]: at the University Press, **1944**. [v]–viii + 91 pages, IV plates (1 in colour) on 2 leaves, illustrations, 19 cm (National Library of Ireland MARC; LCCN a45-001880). US issue by The Macmillan Company, New York ([OL187792M](https://openlibrary.org/books/OL187792M), 1944). Reprinted 1945 ([OL14098622M](https://openlibrary.org/books/OL14098622M)), 1946, 1947, 1948, 1951, and a reset viii + 92 pp. printing by the 1950s–60s ([OL32153687M](https://openlibrary.org/books/OL32153687M), 1962). Price on the first-edition jacket: 6 shillings | | Combined editions | **1956**: *What Is Life? and Other Scientific Essays*, Doubleday Anchor, Garden City NY, viii + 263 pp. ([OL6200338M](https://openlibrary.org/books/OL6200338M)); the title essay reprints the whole 1944 book. **1967**: *What Is Life? The Physical Aspect of the Living Cell & Mind and Matter*, Cambridge University Press, 178 pp., paperback ISBN 052109397X ([OL20969865M](https://openlibrary.org/books/OL20969865M)). **1992**: *What Is Life? with Mind and Matter and Autobiographical Sketches*, Cambridge University Press, Canto series, viii + 184 pp., ISBN 0521427088 ([OL1548875M](https://openlibrary.org/books/OL1548875M)), with a foreword by Roger Penrose and the sketches translated into English for the first time. **2012**: the same volume reissued as **Canto Classics**, ISBN 9781107604667, viii + 184 pp. ([OL25318614M](https://openlibrary.org/books/OL25318614M)); ebook ISBN 9781107295629 (Cambridge Core, DOI [10.1017/CBO9781107295629](https://doi.org/10.1017/CBO9781107295629)) | | *Mind and Matter* | Schrödinger's Tarner Lectures at Trinity College, Cambridge, October 1956; first published by CUP in 1958 | | *Autobiographical Sketches* | Written late in his life; first published in German in *Mein Leben, meine Weltansicht* (Vienna: Zsolnay, 1985); first English translation in the 1992 Canto volume | | Structure (1944 book) | Preface; 7 chapters, each split into many short headed sections ("originally intended to be marginal summaries"); Note to chapter 6; Epilogue "On Determinism and Free Will". About 26,000 words | | Audiobook | **Yes.** *What Is Life? With Mind and Matter and Autobiographical Sketches*, unabridged, read by Bob Souer, Tantor Media, released 22 January 2019, 6 h 8 min (Audible; also on Hoopla and Apple Books) | | Open Library | Work [OL1210514W](https://openlibrary.org/works/OL1210514W) (about 40 editions); author [OL122392A](https://openlibrary.org/authors/OL122392A) | | Cover | [Open Library cover 11024786](https://covers.openlibrary.org/b/id/11024786-L.jpg) (1945 printing) | **Where it came up.** - Video: [Roger Penrose: "My Crazy Idea That Explains the Universe"](https://www.youtube.com/watch?v=iO03t21xhdk), *Curt Jaimungal* (Theories of Everything), published 2025-11-03, 1:56:13. At [1:20:25](https://www.youtube.com/watch?v=iO03t21xhdk&t=4825s) Penrose says he never met Schrödinger (he just missed him in Dublin). He swapped signed copies of *What Is Life?* with Schrödinger's daughter, and he says Schrödinger's semi-popular writing was a model for his own books. (Penrose later wrote the foreword to the 1992 Canto edition.) Earlier, at [29:07](https://www.youtube.com/watch?v=iO03t21xhdk&t=1747s), he names Schrödinger evolution as one of the computable laws, as opposed to collapse. - Video: [The laws of the universe are unable to explain these origin mysteries | Paul Davies: Full Interview](https://www.youtube.com/watch?v=e41IyOlfj7I), *Big Think*, published 2026-11-06, 1:02:05. At [7:56](https://www.youtube.com/watch?v=e41IyOlfj7I&t=476s) Davies uses the book to frame his own working definition of life as chemistry plus information. Schrödinger saw that hereditary information needs quantum-mechanical stability and pictured its carrier as an aperiodic crystal, which later turned out to be DNA. At [28:53](https://www.youtube.com/watch?v=e41IyOlfj7I&t=1733s) (and about [29:34](https://www.youtube.com/watch?v=e41IyOlfj7I&t=1774s)) he returns to chapter 7's claim that we should be ready for a new *kind* of physical law in living matter. This is the basis of his own case for information-based, "top-down" laws. - Requested by Video Summaries on 2026-11-06. The queue note asked for the edition to be verified (done above: CUP 1944; later combined editions 1967, 1992 and 2012). ## 2. Book resources **Reference and catalog pages.** Publisher: [Cambridge Core, Canto Classics edition](https://www.cambridge.org/core/books/what-is-life/30D56B37840DAFB73E580BED1C056919) (contents with page ranges; abstracts). National Library of Ireland: [1944 first edition record](https://catalogue.nli.ie/Record/vtls000459241). Open Library: [OL1210514W](https://openlibrary.org/works/OL1210514W). Wikipedia: [What Is Life?](https://en.wikipedia.org/wiki/What_Is_Life%3F) and [Erwin Schrödinger](https://en.wikipedia.org/wiki/Erwin_Schr%C3%B6dinger). **Copyright status (checked 2026-11-10).** Schrödinger died on 4 January 1961, so the answer depends on where you are: - **Canada: public domain since 1 January 2012.** Canada's term was life + 50 years, and its 2022 change to life + 70 did not bring back works that were already public domain. The same holds in other countries that still use life + 50, and in India (life + 60, public domain since 1 January 2022). - **UK, Ireland, Austria and the rest of the EU: in copyright until the end of 2031** (life + 70), so public domain from 1 January 2032. - **United States: treat it as in copyright, probably through the end of 2039.** A 1944 British book that was still protected at home in 1996 had its US copyright restored for 95 years from publication. There was also a 1944 US issue by Macmillan, which complicates the question in theory, but I found no source treating the book as US public domain. The "public domain in the United States" wording on some print-on-demand reprints (for example the PhilPapers listing) is boilerplate, and I would not rely on it. - The 1992 extras are separate works with their own copyright: Penrose's foreword (Penrose is alive), the English translation of the *Autobiographical Sketches*, and *Mind and Matter* (1958, same dates as above). **No version of the combined Canto volume is free anywhere.** **Free (legal).** - **Faded Page: not there.** Its catalogue search (2026-11-10) has no Schrödinger titles. **Project Gutenberg** (US) and **Gutenberg Canada**: not available. - **Internet Archive / Open Library: yes, borrowable (free with an account).** Lendable scans: the [1945 printing](https://archive.org/details/whatislifephysic0000schr) (viii + 91 pp., with the plates), the [1962 printing](https://archive.org/details/whatislifephysic0000unse), the [1967 *What Is Life? & Mind and Matter*](https://archive.org/details/whatislifephysic0000schr_y5x8), and the [1956 Anchor *What Is Life? and Other Scientific Essays*](https://archive.org/details/whatislifeothers00schr). Start at the [Open Library work page](https://openlibrary.org/works/OL1210514W). - **Unofficial full-text copies.** Retyped PDFs and text files of the 1944 book are posted on the Internet Archive and elsewhere. They are lawful to read in Canada and other life + 50 or life + 60 countries, but not in the US, UK or EU, so I am not linking them. - **Libby/OverDrive: yes, ebook.** [OverDrive 1647](https://www.overdrive.com/media/1647/what-is-life) (Canto combined edition). Whether your library licenses it is a local question. - **Hoopla: yes, audiobook and ebook.** [Audiobook 12295575](https://www.hoopladigital.com/audiobook/what-is-life-erwin-schrodinger/12295575) (the Tantor/Souer recording of the combined edition) and [ebook 18063658](https://www.hoopladigital.com/ebook/what-is-life-the-physical-aspect-of-the-living-cell-erwin-schrodinger/18063658) (*What Is Life?* alone; probably a third-party reprint, so I can't vouch for its text). - **Free companions:** the Nature essay by Philip Ball, ["Schrödinger's cat among biology's pigeons: 75 years of *What Is Life?*"](https://www.nature.com/articles/d41586-018-06034-8) (2018), and the two source interviews. **Paid.** - **Amazon print.** [Canto Classics paperback, ISBN 1107604664](https://www.amazon.com/dp/1107604664) (the edition in print, with *Mind and Matter*, the *Autobiographical Sketches* and Penrose's foreword). Older Canto (ISBN 0521427088) and 1967 CUP paperbacks are easy to find used. - **Kindle.** Yes: [Canto Classics Kindle edition, ASIN B00E3URD7Q](https://www.amazon.com/dp/B00E3URD7Q). - **Audible.** Yes: [Audible author page](https://www.audible.com/author/Erwin-Schrodinger/B000APE8SK) → *What Is Life? With Mind and Matter and Autobiographical Sketches*, read by Bob Souer, 6 h 8 min ([Audible UK listing](https://www.audible.co.uk/pd/What-Is-Life-Audiobook/1541446410)). - **Edition note.** Buy the Canto Classics paperback. For about the price of the short book alone you get *Mind and Matter* and the *Autobiographical Sketches*, and the Canto page numbers below match it. I could not confirm in which printing the Note to chapter 6 first appeared. ## 3. Author biography **Erwin Rudolf Josef Alexander Schrödinger** was born in Vienna on 12 August 1887. He studied at the University of Vienna and served as an artillery officer in the First World War. In 1921 he became professor at Zürich, where in 1926 he published the wave equation that bears his name, the basis of wave mechanics. He succeeded Max Planck in Berlin in 1927 and shared the **1933 Nobel Prize in Physics** with Paul Dirac "for the discovery of new productive forms of atomic theory". He left Germany in 1933 after the Nazis came to power, spent time at Oxford (Magdalen College), and returned to Austria at Graz in 1936. After the Anschluss in 1938 he fled again. Éamon de Valera invited him to Ireland to help found the **Dublin Institute for Advanced Studies**, and he directed its School of Theoretical Physics from 1940 until 1956. The 1943 lectures behind this book were given there. In 1935, in correspondence with Einstein about the EPR paper, he devised the "cat" thought experiment and coined the word "entanglement" (*Verschränkung*). He went back to Vienna in 1956 and died there on 4 January 1961. He is buried in Alpbach, Tyrol. His other general-audience books include *Science and Humanism* (1951), *Nature and the Greeks* (1954), *Mind and Matter* (1958) and *My View of the World* (1961). Technical books include *Statistical Thermodynamics* (1946), *Space-Time Structure* (1950) and *Expanding Universes* (1956). His interest in the Vedanta, which surfaces in the Epilogue here, runs through *Mind and Matter* and *My View of the World*. ## 4. Author interviews and talks Schrödinger died in 1961, so there are no modern interviews. These are the best substitutes: - **The book itself** began as talks: three public lectures at Trinity College, Dublin, in February 1943, to an audience of about four hundred (ch. 1). He calls them not "popular", even though "the physicist's most dreaded weapon, mathematical deduction, would hardly be utilized". - **Nobel lecture (12 December 1933)**: ["The fundamental idea of wave mechanics"](https://www.nobelprize.org/prizes/physics/1933/schrodinger/lecture/), nobelprize.org. - **Roger Penrose on the book**: the source video ([1:20:25](https://www.youtube.com/watch?v=iO03t21xhdk&t=4825s)) and his foreword to the Canto edition, which the 2021 *Cell Systems* anniversary essay (below) quotes as calling the book "among the most influential scientific writings of the 20th century". - **Paul Davies on the book**: the source interview ([7:56](https://www.youtube.com/watch?v=e41IyOlfj7I&t=476s)), and his book *The Demon in the Machine* (2019), which opens from Schrödinger's question. - **Anniversary retrospectives**: Trinity College Dublin's 2018 conference "Schrödinger at 75: The Future of Biology", and the 1993 collection *What Is Life? The Next Fifty Years*, ed. Michael P. Murphy and Luke A. J. O'Neill (CUP, 1995), from Trinity's 50th-anniversary meeting. ## 5. Summary **Thesis.** The Preface makes the case for a physicist stepping outside his field: we have "inherited from our forefathers the keen longing for unified, all-embracing knowledge", but no single mind can now master more than "a small specialized portion of it". So "some of us should venture to embark on a synthesis of facts and theories, albeit with second-hand and incomplete knowledge of some of them – and at the risk of making fools of ourselves." Chapter 1 then states the one question and the preliminary answer: "The obvious inability of present-day physics and chemistry to account for such events is no reason at all for doubting that they can be accounted for by those sciences." The organism differs from anything physicists have studied because its key part, "the chromosome fibre", is "an aperiodic crystal". The difference is like that "between an ordinary wallpaper in which the same pattern is repeated again and again in regular periodicity and a masterpiece of embroidery, say a Raphael tapestry". The motto is Spinoza, *Ethics* IV, prop. 67: a free man thinks of nothing less than of death, and his wisdom is a meditation on life. **Outline.** Page ranges are from the Canto Classics contents (2012; same as the 1992 Canto). Section headings are Schrödinger's own (the first headings of chs. 1 and 4 are missing from the copy I read and are given from the standard text). *Front matter (Canto).* Contents (v–viii); half-title "What Is Life?" (ix); Foreword by Roger Penrose (x; not read); Preface (1–2). - **Ch. 1, The Classical Physicist's Approach to the Subject (pp. 3–18).** *The general character and purpose of the investigation; Statistical physics, the fundamental difference in structure; The naive physicist's approach to the subject; Why are the atoms so small?; The working of an organism requires exact physical laws; Physical laws rest on atomic statistics and are therefore only approximate; Their precision is based on the large number of atoms intervening (first example, paramagnetism; second, Brownian movement and diffusion; third, limits of accuracy of measuring); The √n rule.* The "naive physicist" (Schrödinger says it was himself) turns "Why are atoms so small?" into "Why must our bodies be so large compared with the atom?" His answer: thought is orderly, so the organ of thought must follow exact laws, and in physics exact laws are statistical, holding only for huge numbers of atoms. Paramagnetism (Langevin, Curie's law), Brownian motion and diffusion show order emerging from random heat motion. The torsion balance shows why too-sensitive senses would be useless. The **√n rule**: a law built from n molecules is inaccurate by about 1/√n, so a million atoms give only one part in a thousand, which is too crude for a "Law of Nature". Lord Kelvin's image: mark the molecules in a glass of water, pour it into the ocean and mix, and any glassful will contain about a hundred of them. - **Ch. 2, The Hereditary Mechanism (pp. 19–31).** *The classical physicist's expectation, far from being trivial, is wrong; The hereditary code-script (chromosomes); Growth of the body by cell division (mitosis); In mitosis every chromosome is duplicated; Reductive division (meiosis) and fertilization (syngamy); Haploid individuals; The outstanding relevance of the reductive division; Crossing-over, location of properties; Maximum size of a gene; Small numbers; Permanence.* The twist: "incredibly small groups of atoms, much too small to display exact statistical laws, do play a dominating role" in heredity. The chromosomes hold "in some kind of code-script the entire pattern of the individual's future development". A Laplacean mind could read from them whether the egg will become "a black cock or into a speckled hen, into a fly or a maize plant, a rhododendron, a beetle, a mouse or a woman". They are "law-code and executive power – or, to use another simile, they are architect's plan and builder's craft – in one." A body cell is only the 50th or 60th "descendant" of the egg. Every cell carrying the whole code is compared to General Montgomery briefing every soldier on his plans. Crossing-over maps and Drosophila salivary-gland bands put the **maximum size of a gene** at a cube about 300 Å across, "not more than about a million or a few million atoms". That is too few for statistical law, yet the whole "four-dimensional pattern" is passed on almost unchanged for centuries. - **Ch. 3, Mutations (pp. 32–45).** *"Jump-like" mutations, the working-ground of natural selection; They breed true; Localization, recessivity and dominance; Introducing some technical language; The harmful effect of close-breeding; General and historical remarks; The necessity of mutation being a rare event; Mutations induced by X-rays; First law (mutation is a single event); Second law (localization of the event).* De Vries's discontinuous mutations, not Darwin's small continuous variations, are what selection works on ("Darwin was mistaken", he says). Mutations breed true and are usually recessive and harmful, hence the risk of inbreeding. They must be rare to be useful. X-ray experiments (he follows Timoféeff-Ressovsky's 1934 review) show that the mutation rate is proportional to dose, so a mutation is a single event, an ionization within a "target" of roughly "ten average atomic distances cubed", "only about 10³ = a thousand atoms" (the Delbrück estimate). - **Ch. 4, The Quantum-Mechanical Evidence (pp. 46–55).** *Permanence unexplicable by classical physics; Explicable by quantum theory; Quantum theory – discrete states – quantum jumps; Molecules; Their stability dependent on temperature; Mathematical interlude; First amendment; Second amendment.* His showcase of permanence is the Habsburg lip ("Habsburger Lippe"), inherited faithfully for centuries by a structure of perhaps a thousand atoms kept at body temperature. Only quantum theory explains how so few atoms stay stable: "the mechanism of heredity is closely related to, nay, founded on, the very basis of quantum theory." Atoms in a molecule sit in discrete energy levels and are held by the Heitler–London bonds (1927). Changing configuration needs an activation energy W, and the expected waiting time grows exponentially with W/kT. Following Delbrück: about 1/10 s at W = 30 kT, 16 months at 50 kT, 30,000 years at 60 kT. Small changes in the barrier therefore give enormous differences in stability. - **Ch. 5, Delbrück's Model Discussed and Tested (pp. 56–66).** *The general picture of the hereditary substance; The uniqueness of the picture; Some traditional misconceptions; Different "states" of matter; The distinction that really matters; The aperiodic solid; The variety of contents compressed in the miniature code; Comparison with facts: degree of stability, discontinuity of mutations; Stability of naturally selected genes; The sometimes lower stability of mutants; Temperature influences unstable genes less than stable ones; How X-rays produce mutation; Their efficiency does not depend on spontaneous mutability; Reversible mutations.* The gene is "a huge molecule, capable only of discontinuous change", and a mutation is a rearrangement to an isomer across an energy barrier. This is the model of Timoféeff-Ressovsky, Zimmer and Delbrück (1935). A molecule and a crystal are really the same kind of thing, both held by the same bonds; the real distinction is bonded versus unbonded atoms. Hence: "We believe a gene – or perhaps the whole chromosome fibre – to be an aperiodic solid." The **Morse-code argument** for the "miniature code": dots and dashes in groups of up to four give 30 signs; three signs in groups of up to ten give 88,572; five signs in groups up to 25 give 372,529,029,846,191,405. So a small molecule can encode "a highly complicated and specified plan of development". Tests: natural genes are very stable (high W) while some mutants are less stable, and warmth raises the mutation rate of stable genes more than of unstable ones, as the formula predicts. - **Ch. 6, Order, Disorder and Entropy (pp. 67–75).** *A remarkable general conclusion from the model; Order based on order; Living matter evades the decay to equilibrium; It feeds on "negative entropy"; What is entropy?; The statistical meaning of entropy; Organization maintained by extracting "order" from the environment; Note to chapter 6.* The key sentence: "living matter, while not eluding the 'laws of physics' as established up to date, is likely to involve 'other laws of physics' hitherto unknown, which, however, once they have been revealed, will form just as integral a part of this science as the former." He confesses this was "my only motive for writing this book". A living thing avoids "the decay into equilibrium" (death, maximum entropy) by "continually drawing from its environment negative entropy … What an organism feeds upon is negative entropy." He gives Boltzmann's entropy = k log D, with D a measure of disorder, so that −(entropy) = k log(1/D) measures order. Plants take theirs from sunlight. In the **Note to chapter 6** he answers physicists who objected: for them he would have said **free energy**. He also concedes Franz Simon's point that we need food in "the extremely well ordered state of more or less complicated organic compounds", not just any low-entropy fuel, and that giving off heat is how warm-blooded animals export entropy. - **Ch. 7, Is Life Based on the Laws of Physics? (pp. 76–85).** *New laws to be expected in the organism; Reviewing the biological situation; Summarizing the physical situation; The striking contrast; Two ways of producing orderliness; The new principle is not alien to physics; The motion of a clock; Clockwork after all statistical; Nernst's theorem; The pendulum clock is virtually at zero temperature; The relation between clockwork and organism.* "We must be prepared to find a new type of physical law prevailing in it." There are "two different 'mechanisms'" of order: "the 'statistical mechanism' which produces order from disorder and the new one, producing order from order". He cites Planck's paper on "dynamical" and "statistical" laws. But the new principle "is a genuinely physical one: it is, in my opinion, nothing else than the principle of quantum theory over again". A clock looks like pure "order from order" yet is statistical underneath. By Nernst's heat theorem, a system near enough to absolute zero behaves "dynamically", and a pendulum clock is "virtually at zero temperature" because its solid parts are held by Heitler–London forces far stronger than heat motion. The organism is like it: it "hinges upon a solid – the aperiodic crystal". But its single cog "is not of coarse human make, but is the finest masterpiece ever achieved along the lines of the Lord's quantum mechanics." - **Epilogue, On Determinism and Free Will (pp. 86–90).** The bodily events behind thought are "if not strictly deterministic at any rate statistico-deterministic", and "quantum indeterminacy plays no biologically relevant role in them". From two premises, (i) "My body functions as a pure mechanism according to the Laws of Nature" and (ii) "I know, by incontrovertible direct experience, that I am directing its motions", he infers "that I – I in the widest meaning of the word, that is to say, every conscious mind that has ever said or felt 'I' – am the person, if any, who controls the 'motion of the atoms' according to the Laws of Nature." In Christian terms "Hence I am God Almighty" sounds "both blasphemous and lunatic". In the Upanishads, "ATHMAN = BRAHMAN" (the personal self equals the omnipresent, all-comprehending eternal self) is the deepest insight, and the mystics' phrase is "DEUS FACTUS SUM". "Consciousness is never experienced in the plural, only in the singular." Plurality is *maya*, like Gaurisankar and Mount Everest "turned out to be the same peak seen from different valleys". What we call "I" is "the canvas upon which they are collected", so "In no case is there a loss of personal existence to deplore. Nor will there ever be." (It is reported that the Epilogue's religious content made the first publisher, an Irish house, back out, which is why Cambridge published it. I did not verify this story; see the fact-check.) *The rest of the Canto volume (not read; from contents and publisher's text).* - **Mind and Matter (pp. 91–164).** The 1956 Tarner Lectures: Dedication (92); 1, The Physical Basis of Consciousness (93–102); 2, The Future of Understanding (103–116); 3, The Principle of Objectivation (117–127); 4, The Arithmetical Paradox: The Oneness of Mind (128–139); 5, Science and Religion (140–152); 6, The Mystery of the Sensual Qualities (153–164). The publisher describes it as asking "what place consciousness occupies in the evolution of life". The chapter titles show it develops the Epilogue's theme of one mind. - **Autobiographical Sketches (pp. 165–184).** A short, fragmentary memoir: childhood in Vienna, the war, the career years and the exile. **Key ideas.** - **Heredity is a physics problem about small numbers.** Genes hold too few atoms for statistical laws, yet they are stable for centuries. Only quantum-mechanical bonding, with high activation barriers, explains that. - **The gene is an aperiodic crystal.** It is solid like a crystal, but without repetition, so it can carry a "code-script" that is also an "executive power". His Morse-code count shows how much a small molecule can hold. - **Life feeds on negative entropy.** Organisms keep their order by exporting entropy to their surroundings. He later said "free energy" would have been the more technical term. - **Order from order.** Living things copy existing order instead of producing it from molecular chaos, and he holds that this rests on nothing beyond "the principle of quantum theory over again". - **Expect new laws, not new forces.** Living matter obeys physics but may reveal "other laws of physics" hitherto unknown. Davies takes this up directly in the source interview. - **One mind.** The Epilogue resolves free will versus mechanism by identifying the self with a single universal consciousness, as in Vedanta. **Reception, in brief.** Much read and much argued over. Francis Crick wrote to Schrödinger in 1953 that he and Watson had "both been influenced by your little book" (Ball, *Nature*, 2018). Watson also credited it with turning him toward the gene, and Maurice Wilkins cited it as well. Biologists and chemists were more critical. Max Perutz's 1987 *Nature* essay "Physics and the riddle of life" judged, in paraphrase, that what was true in the book was not original and much of what was original was known not to be true when it was written. He faulted it for overlooking the biochemistry already known and for its loose use of "negative entropy". Linus Pauling objected along similar lines. Historians (Robert Olby, Evelyn Fox Keller, Lily Kay) see its real influence in the "information" and "code" language it helped bring into biology. Penrose's foreword calls it one of the most influential scientific writings of the century. The Trinity College meetings in 1993 and 2018 used it as a programme for biology's open questions. ## 6. Fact-check Overall verdict: **mixed**. The core ideas held up remarkably well: a stable, quantum-bonded, non-repeating molecule carrying a code; mutation as a single molecular event; organisms exporting entropy. Several specifics were wrong even by 1950s knowledge, and some were not original. | Claim | Verdict | Evidence | |---|---|---| | Based on lectures at Trinity College Dublin, February 1943, under the Dublin Institute for Advanced Studies; CUP 1944; viii + 91 pp. | Supported | Title page and Preface ("Dublin September 1944"); NLI MARC record; Open Library 1944/45 editions | | Combined editions: with *Mind and Matter* (1967); with *Autobiographical Sketches* and Penrose foreword (Canto 1992; Canto Classics 2012) | Supported | Open Library OL20969865M, OL1548875M, OL25318614M; Cambridge Core contents ("Foreword by Roger Penrose") | | The hereditary material is an "aperiodic crystal/solid" carrying a "code-script" | Supported in principle | DNA's sequence is exactly a non-repeating, stable code (Watson & Crick, *Nature* 171, 737, 1953). The term "code" here is Schrödinger's metaphor; the genetic code was worked out 1961–66 | | The gene is "probably a large protein molecule" (ch. 2) | Wrong | Avery, MacLeod & McCarty (1944, the same year) showed DNA carries hereditary information in pneumococcus; Hershey & Chase (1952) | | Humans have 48 chromosomes (2 × 24) (ch. 2) | Wrong (the standard figure in 1944) | 46, established by Tjio & Levan, *Hereditas* 42 (1956) 1–6 | | A mutation target is about 1,000 atoms; a gene at most "a million or a few million atoms" (chs. 2–3) | Order-of-magnitude for its time, now superseded | From Timoféeff-Ressovsky, Zimmer & Delbrück (1935); real genes span thousands of base pairs, about 10⁵–10⁶ atoms, and one base change can be a mutation | | Mutation rate is proportional to X-ray dose, so a mutation is a single event (ch. 3) | Supported | Muller 1927; Timoféeff-Ressovsky, *Biological Reviews* 9 (1934) 411, which he cites; the linear dose relation held at those doses | | Darwin was mistaken: selection works on discontinuous mutations, not small continuous variation (ch. 3) | Outdated | The 1930s–40s modern synthesis (Fisher, Haldane, Wright) showed small-effect mutations and continuous variation are the main stuff of selection. Schrödinger was following de Vries's mutationism | | Waiting time 1/10 s at W = 30 kT, 16 months at 50 kT, 30,000 years at 60 kT (ch. 4) | Supported as an illustration | Arrhenius/Polanyi–Wigner form t = τ e^(W/kT) with τ ≈ 10⁻¹³–10⁻¹⁴ s gives values of this order; the figures are Delbrück's, as Schrödinger says | | Morse-code counts: 30; 88,572; 372,529,029,846,191,405 (ch. 5) | Supported | Arithmetic checked: 2+4+8+16 = 30; Σ3ᵏ (k = 1–10) = 88,572; Σ5ᵏ (k = 1–25) = 372,529,029,846,191,405. His count for exactly five of each of five signs, "more than 62,330,000,000,000", understates the exact 25!/(5!)⁵ = 623,360,743,125,120 by about a factor of 10 (a slip in the original or in the copy I read) | | Boltzmann constant = 3.2983 × 10⁻²⁴ cal/°C (ch. 6) | Supported (1940s value) | Today 1.380649 × 10⁻²³ J/K ÷ 4.184 = 3.2998 × 10⁻²⁴ cal/K | | Organisms "feed on negative entropy" (ch. 6) | Supported, with his own qualification | Correct thermodynamics: organisms export entropy. Physicists objected that free energy is the right quantity, which he concedes in the Note to ch. 6. Brillouin later coined "negentropy" (1953) | | Life may involve "other laws of physics hitherto unknown", but the principle is just quantum theory (chs. 6–7) | Open / partly superseded | Molecular biology so far has needed no new physics. Davies (source video, 28:53) and others still argue for new information-based laws. A debate, not a result | | Quantum indeterminacy plays no biologically relevant role (Epilogue) | Mostly supported; open at the edges | Mainstream view; "quantum biology" (photosynthetic transfer, enzyme tunnelling, bird magnetoreception) finds quantum effects, but not ones bearing on free will. Penrose–Hameroff's Orch OR disputes it (see Penrose dossiers) | | Crick and Watson credited the book | Supported | Crick letter to Schrödinger, 12 August 1953 ("both been influenced by your little book"), quoted in Ball, *Nature* 560 (2018) 548; Watson's memoirs | | Its ideas were largely not original | Partly supported | Delbrück's 1935 model (the "Three-Man Paper"), Muller and Koltsov anticipated the molecular gene and mutation by quantum jumps; Perutz, *Nature* 326 (1987) 555. But the "code-script" framing and the thermodynamic argument for a general reader were Schrödinger's own | | The Epilogue's religious content made an Irish publisher refuse the book, hence CUP | Unverified | Told by Walter Moore in *Schrödinger: Life and Thought* (CUP, 1989), naming Dublin's Cahill & Co.; I did not see the primary source | | Public domain in Canada; still in copyright in the US and EU/UK | Supported (legal analysis, not legal advice) | Death 1961; Canada life + 50 for deaths before 1972; EU/UK life + 70 (to end 2031); US restoration under 17 U.S.C. §104A (URAA) for foreign works protected at home in 1996, 95-year term | ## 7. Citations and references **What the book draws on.** Few footnotes; the sources named in the text are: N. W. Timoféeff-Ressovsky, K. G. Zimmer and M. Delbrück, "Über die Natur der Genmutation und der Genstruktur", *Nachr. Ges. Wiss. Göttingen* (1935), "the principal source" for chs. 4–5; Timoféeff-Ressovsky's review in *Biological Reviews* 9 (1934); C. D. Darlington and J. B. S. Haldane on gene size and structure; Muller on X-ray mutation; de Vries, Correns and Tschermak (1900) and de Vries's mutation papers (1901–03); Mendel; Darwin; W. Heitler and F. London (1927) on the chemical bond; M. Polanyi and E. Wigner on reaction rates; P. Langevin and Curie's law; Boltzmann and Gibbs; Max Planck, "Dynamische und statistische Gesetzmäßigkeit"; Nernst's heat theorem; F. Simon (Note to ch. 6); Spinoza's *Ethics*; the Upanishads; Schopenhauer; and Kant. **Related works.** Schrödinger, *Mind and Matter* (1958; in the Canto volume) and *My View of the World* (1961), which carry on the Epilogue; *Science and Humanism* (1951) and *Nature and the Greeks* (1954). Michael P. Murphy and Luke A. J. O'Neill (eds.), *What Is Life? The Next Fifty Years* (CUP, 1995). Paul Davies, *The Demon in the Machine* (2019) and *The Fifth Miracle* (1998). Addy Pross, *What Is Life? How Chemistry Becomes Biology* (2012). Paul Nurse, *What Is Life?* (2020). James Watson, *The Double Helix* (1968). Walter Moore, *Schrödinger: Life and Thought* (1989). Penrose, [[Book Summaries/Penrose, Roger/The Emperor's New Mind - Roger Penrose|The Emperor's New Mind]] (1989). The Penrose video also names Shan Gao (ed.), *Consciousness and Quantum Mechanics*, next in the [[Book Summaries/Queue|Queue]]. **Links this note used:** - Catalogs and editions: [Cambridge Core, Canto Classics](https://www.cambridge.org/core/books/what-is-life/30D56B37840DAFB73E580BED1C056919); [NLI 1944 record](https://catalogue.nli.ie/Record/vtls000459241); [Open Library OL1210514W](https://openlibrary.org/works/OL1210514W); [OL187792M](https://openlibrary.org/books/OL187792M); [OL14098622M](https://openlibrary.org/books/OL14098622M); [OL32153687M](https://openlibrary.org/books/OL32153687M); [OL20969865M](https://openlibrary.org/books/OL20969865M); [OL1548875M](https://openlibrary.org/books/OL1548875M); [OL25318614M](https://openlibrary.org/books/OL25318614M); [OL6200338M](https://openlibrary.org/books/OL6200338M); [cover 11024786](https://covers.openlibrary.org/b/id/11024786-L.jpg); IA scans [whatislifephysic0000schr](https://archive.org/details/whatislifephysic0000schr), [whatislifephysic0000unse](https://archive.org/details/whatislifephysic0000unse), [whatislifephysic0000schr_y5x8](https://archive.org/details/whatislifephysic0000schr_y5x8), [whatislifeothers00schr](https://archive.org/details/whatislifeothers00schr); [Faded Page search](https://www.fadedpage.com/csearch.php) (no Schrödinger titles, 2026-11-10). - Shops and libraries: [Amazon Canto Classics paperback](https://www.amazon.com/dp/1107604664); [Kindle B00E3URD7Q](https://www.amazon.com/dp/B00E3URD7Q); [Audible author page](https://www.audible.com/author/Erwin-Schrodinger/B000APE8SK); [Audible UK](https://www.audible.co.uk/pd/What-Is-Life-Audiobook/1541446410); [OverDrive 1647](https://www.overdrive.com/media/1647/what-is-life); [Hoopla audiobook](https://www.hoopladigital.com/audiobook/what-is-life-erwin-schrodinger/12295575); [Hoopla ebook](https://www.hoopladigital.com/ebook/what-is-life-the-physical-aspect-of-the-living-cell-erwin-schrodinger/18063658). - Commentary: [Ball, *Nature* 2018](https://www.nature.com/articles/d41586-018-06034-8); [*Cell Systems*, "Schrödinger's What Is Life? at 75" (2021)](https://www.cell.com/cell-systems/fulltext/S2405-4712(21)00199-X); [Wikipedia, What Is Life?](https://en.wikipedia.org/wiki/What_Is_Life%3F); [Nobel lecture 1933](https://www.nobelprize.org/prizes/physics/1933/schrodinger/lecture/). - Source videos: [Roger Penrose: "My Crazy Idea That Explains the Universe"](https://www.youtube.com/watch?v=iO03t21xhdk); [[Video Summaries/Curt Jaimungal/Roger Penrose My Crazy Idea That Explains the Universe]]; [Paul Davies: Full Interview, Big Think](https://www.youtube.com/watch?v=e41IyOlfj7I); [[Video Summaries/Big Think/The laws of the universe are unable to explain these origin mysteries Paul Davies Full Interview]].