What Is Life? published in 1944. At that time DNA was not yet accepted as the carrier of hereditary information, which only was the case after the Hershey–Chase experiment of 1952. One of the most successful branches of physics at this time was statistical physics, and quantum mechanics, a theory which is also very statistical in its nature. Schrödinger himself is one of the founding fathers of quantum mechanics. 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?", geneticist and 1946 Nobel-prize winner H. J. Muller had in
N-entity the lowest, "i.e.", the physical layer, to the highest, so that the -th layer is above the "n"-th layer and the -th layer is below. N-entity In telecommunication, a "n"-entity is an active element in the "n"-th layer of the Open Systems Interconnection--Reference Model (OSI-RM) that (a) interacts directly with elements, "i.e.", entities, of the layer immediately above or below the "n"-th layer, (b) is defined by a unique set of rules, "i.e.", syntax, and information formats, including data and control formats, and (c) performs a defined set of functions. The "n" refers to any one of the 7 layers