Ervin Bauer's concept of biological thermodynamics and its different evaluations.

The development of biological concepts in the 19th century was followed by the emergence of approaches to formulate the principles of theoretical biology. Ervin Bauer in 1920, and in more detail in 1935, suggested the basic principle that can be accepted as the fundamental law of biology: "The living systems are never in equilibrium; at the expense of their free energy they constantly perform work to avoid the equilibrium required by the laws of physics and chemistry under existing external conditions." Many researchers interpreted biology with the help of physical quantities but Bauer was the first to build a general and already molecular-based biological theory. The main point of Bauer's concept is not the non-equilibrium, but the function of organism producing the non-equilibrium, the capacity for self-adaptation, and the power for changing its functions in such a way that the system gets the state of non-equilibrium always anew. We will discuss Bauer's theorem, the contemporaneous objections, and the divergent opinions about his work by succeeding generations of scientists.