International Encyclopedia of Systems and Cybernetics

In its original limited sense, thermodynamics covers the relationship of heat with other forms of energy (1st Law).

The progressive decay of high energy into equalized heat led to the concept of entropy and to thermodynamics properly (2nd. Law).

Both the 1st and the 2nd law apply necessarily to systems and become in this way connected with the notions of organization and flows.

The 2nd Law was given a statistical interpretation by L. BOLTZMANN, in which maximum internal entropy corresponds to perfectly scattered and equal distribution of (thermal) energy. But the notion of entropy led to contradictions related to the possibility of systems to fight the downgrading of their internal organization (MAXWELL's demon paradox).

These contradictions led in turn to a deeper reflexion about the interrelations of the system with its environment (SZILARD's "exorcism" on MAXWELL's demon, 1929) and it became clear that the isolated system is a purely abstract and ad hoc concept.

Any concrete system as observed by J.H. VOGEL, is to itself a black box that constrains its relations with an environment by specifying inputs and outputs conditions (1988, p.300).

It was now necessary to explain why and how concrete systems could maintain their organization against the effects of the 2nd Law, This was the first stage of PRIGOGINE's research, who explained the ways in which an open system could remain organized by importing energy from its environment, stabilize at the lowest, most "economic" possible level its production of entropy and exporting this entropy to its environment (Theorem of minimum entropy production).

Remained still to understand how systems of a higher degree of internal organization could appear in a universe generally dominated by the 2nd Law. This was the second stage of PRIGOGINE's work, who used the concepts of giant fluctuations, dissipative structuration and bifurcations, all related to the dissipation of a flow of energy, to explain the emergence of upgraded organization. In R. LEFEVER's words: "In contact with a source rich in free energy, the system is able to maximize its exchanges with the environment and to enter in an evolutive feedback" (1979, p.24).

The whole of thermodynamics is thus part of the fundamental bedrock of systemics.