To a good approximation, one of the most oft-quoted references in thermodynamics is Erwin Schrödinger’s 1944 postulate that an organism keeps itself alive or aloof by feeding on negative entropy from its environment.[8] From the famous chapter six “Order, Disorder and Entropy” of his book What is Life?, Schrödinger asks: “what is the characteristic feature of life? and “when is a piece of matter said to be alive?” To answer these questions, Schrödinger turns to thermodynamics. Life, according to Schrödinger, avoids a decay to maximum entropy, or thermodynamic equilibrium, which Schrödinger equates with death, by feeding on negative entropy. Specifically, according to Schrödinger, an organism avoids decay by eating, drinking, breathing, and in the case of plants assimilating, a process called metabolism.
In the past, Schrödinger states, this process would have been considered an exchange of matter or energy, such that organisms stay alive by exchanging energy. He uses the example of how caloric values are printed in certain menus in the United States or Germany, but states that these caloric energy exchange values are useless in trying to quantify life. He then asks “what then is that precious something contained in our food which keeps us from death?” The answer, according to Schrödinger, is that because according the second law of thermodynamics an organism continually produces “positive entropy” it must continually draw in “negative entropy” from its environment to stay alive. Or, specifically “the essential thing in metabolism is that the organism succeeds in freeing itself from all the entropy it cannot help producing while alive.”
These suppositions, because they were intended for a lay audience, however, met with great opposition in the physics community. In later editions of his book, Schrödinger attached a note to chapter six explaining his use of the term “negative entropy”. He states “the remarks on negative entropy have met with doubt and opposition from physicist colleagues. Let me say first, that if I had been catering for them alone I should have let the discussion turn on free energy instead. It is the more familiar notion in this context. But this highly technical term seemed too linguistically near to energy for making the average reader alive to the contrast between the two things.”
