International Encyclopedia of Systems and Cybernetics

The rate at which entropy is produced by an energy fed system.

Dissipation is concomitant with the existence of nonequilibrium conditions within concrete systems.

Energy can be dissipated in three different ways:

1) "by microscopic interactions between entities in a virtually homogeneous or "incoherent" field" (F. ROBB, 1990, p. 138). This type of dissipation is dealt with by the purely abstract model of entropy growth in isolated systems (i.e. deprived of inputs) proposed by classical thermodynamics.

2) According to PRIGOGINE's theorem of minimum entropy production in homeostatic systems at a given level of complexity and in their state of maturity. This is thus expressed by M. CEREIJIDO: "The system tends toward structures which will permit it to maintain its entropy production at the lowest possible level (until it reaches) more equilibrated structures with the minimum dissipation" (1978, p.97). This is L. ONSAGER's Minimum Dissipation Principle, according to which replication of systemic structures has a lower entropy cost that creation of new structures by dissipation (1931 , p.405-26). This is consonant with the acquisition of stability by autopoietic systems as well as with BENARD's dissipative structuration, once the system stabilizes, and structures are only maintained through a minimum dissipation rate, or least dissipation, regulating the energy flow to a minimum compatible with the system's survival.

This kind of dissipation is proper to systems submitted to wear, and end by final breakdown (see "eigen time").

3) "by the emergence of a new higher order entity, a "coherent" field which dissipates even more energy (by increasing the area of the dissipative surface)" (F. ROBB, 1990, p.138). R.N. ADAMS in turn, writes: "The dissipation of expanding systems increases the amounts and varieties of energy forms being incorporated and thus also the low- quality energy and waste material eliminated or marginalized because it cannot be processed inside the structure. Hence, dissipation not only creates areas of control (certainly within the structure, and sometimes outside it) but also creates areas beyond control… Thus the act of dissipation creates in the environment new dynamic factors in natural selection" (1988, p.136).

In the second as well as in the third case, dissipative structures must sustain themselves in a dynamic way by permanently obtaining from a specific environment the needed energy inputs. As observed by R.N. ADAMS: "For them construction and destruction are simultaneous. In organisms, old cells dissipate while new cells are formed; in societies, people die and are replaced by new people who are taught by the old" (p .60).

Systemic complexity is proportional to energy dissipation. Or, in other words, systems are entropy accelerators and the more complex ones are the strongest accelerators.

Of course, any system depends on its environment to obtain the energy it needs for dissipation and, globally, the 2nd. law of thermodynamics is respected, even if locally, within the system, a more complex degree of organization appears.

As to the ultimate nature of dissipation, it seems to be some sort of general cosmic dynamics. The rumanian physicist S. LUPASCO (1900-1988) who developed his views in France, sees this cosmic dynamics as reflected into the opposition between the 2. Principle of Thermodynamics (which prescribes the unilateral and irreversible degradation of the quality of energy) and PAULI's Exclusion Principle, according to which any two particles can never have their four basic quantum numbers identical (1974). This prescribes obviously a very basic condition for the organization of the material world, that LUPASCO describes as "energetic antagonism".

Such an antagonism is clearly visible in the genesis of material forms (D'Arcy THOMPSON, 1916, Ch. Laville, 1950)

→ Entropy production (Theorem of Minimum); Fields (Interactions between); Form and Force ; Morphogenetic field; Structure (Dissipative); Symmetry breaking; Vortex