Тіршілік дегеніміз не? Жас клетканың физикалық аспектісі

1944 non fiction science book by Erwin Schrödinger

What Is Life? The Physical Aspect of the Living Cell is a 1944 science book written for the lay reader by physicist Erwin Schrödinger. The book was based on a course of public lectures delivered by Schrödinger in February 1943, under the auspices of the Dublin Institute for Advanced Studies, where he was Director of Theoretical Physics, at Trinity College, Dublin. The lectures attracted an audience of about 400, who were warned "that the subject matter was a difficult one and that the lectures could not be termed popular, even though the physicist’s most dreaded weapon, mathematical deduction, would hardly be utilized." Schrödinger's lecture focused on one important 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?"

The book, published in 1944, is based on lectures delivered under the auspices of the Dublin Institute for Advanced Studies at Trinity College, Dublin in February 1943, attended by Éamon de Valera and his cabinet. At that time, although DNA was known to be a constituent of cell nuclei, it had not yet been identified with certainty as the molecular basis of inheritance, and the concept of a "heredity molecule" was strictly theoretical, with various candidates. One of the most successful branches of physics at this time was statistical physics. Schrödinger himself is one of the founding fathers of quantum mechanics, a theory which is also very statistical in its nature. Max Delbrück's thinking about the physical basis of life was an important influence on Schrödinger. However, long before the publication of What is Life?, the American geneticist Hermann J. Muller, who would later win a Nobel Prize in 1946, had in his 1922 article "Variation due to Change in the Individual Gene" already laid out all the basic properties of the "heredity molecule" (not yet known to be DNA) which Schrödinger re derived in 1944 "from first principles" in What is Life? (including the "aperiodicity" of the molecule), properties which Muller specified and refined additionally in his 1929 article "The Gene As The Basis of Life" and during the 1930s. Muller himself wrote in a 1960 letter to a journalist regarding What Is Life? that whatever the book got right about the "hereditary molecule" had already been published before 1944 and that Schrödinger's were only the wrong speculations; Muller also named two famous geneticists, including Delbrück, who knew every relevant pre 1944 publication and had been in contact with Schrödinger before 1944. DNA as the molecule of heredity became foremost only after Oswald Avery's bacterial transformation experiments published in 1944; before those experiments, proteins were considered the most likely candidates. DNA was confirmed as the molecule in question by the
Hershey–Chase experiment conducted in 1952.

In a world governed by the second law of thermodynamics, all isolated systems are expected to approach a state of maximum disorder or entropy: an irreversible state of thermodynamic equilibrium, where free energy is no longer available to do work. It has been argued that, since life approaches and maintains a highly ordered state, it violates the aforementioned second law, implying that there is a paradox. However, since the biosphere is not an isolated system, there is no paradox. The increase of order inside an organism is more than paid for by an increase in disorder outside this organism by the loss of heat into the environment. By this mechanism, the second law is obeyed, and life maintains a highly ordered state, which it sustains by causing a net increase in disorder in the Universe. In order to increase the complexity on Earth—as life does—free energy is needed, and in this case is provided by the Sun.

Erwin Schrödinger (1944), What Is Life? and Other Scientific Essays. Based on lectures delivered under the auspices of the Dublin Institute for Advanced Studies at Trinity College, Dublin, in February 1943. Doubleday (1956) and Internet Archive.