International Encyclopedia of Systems and Cybernetics

1. Property of a system able to reach a final state starting from different initial conditions and by different ways (Adapted from J.G. MILLER, 1978, p.41).

The equifinality concept was introduced by L.von BERTALANFFY (1940, p.521).

Equifinality is possibly more a seeking behavior than a property.

MILLER gives anyhow, on basis of the equifinality property, a new interpretation of DRIESCH's experiment of cutting an embryo of a sea urchin in two halves, each of which remains still able to produce a normal sea urchin.

Thus a cybernetic-systemic understanding of a general process replaces a vitalistic interpretation.

MILLER writes: "The obvious purposive activities of most living systems, which may have seemed to many to require a vitalistic or teleological interpretation, can be explained as open-system characteristics by means of this principle. Some open physical systems also have this characteristic" (p.41).

Equifinality operates by regulating feedbacks and becomes more efficient when the system is endowed with more variety.

However as noted by Stafford BEER, "death is equifinal" as a result of the ageing process in any autopoietic system, definitively unable to escape from organizational closure (as anyone of us).

Another shade of meaning is equifinality by irreversible thermodynamic transformation towards a state of maximum entropy: "Given the final state with maximal entropy, it is impossible to know which initial state led to this result" (F. HEYLIGHEN, 1989, p.366).

2. "The ability of living organisms to reach an initially predetermined final state in spite of perturbations in the initial conditions (proceeding from different initial states and by different routes)" (I.V. BLAUBERG, V.N. SADOVSKY & E.G. YUDIN, 1977, p.49).

BLAUBERG et al add: "In closed systems their final states (e.g. distribution of matter concentrations) are entirely determined by the initial states, which is reflected in the corresponding "mechanistic" formalism" (Ibid).

Let us remember the ambiguity of the "closed system" model.

R. ROSEN describes equifinality as "… the stubborn tendency of a developing system to reach the same final state despite such experimental interventions as amputations, randomization or hybridization" (1979, p.176).

The predetermined character of the final state is a necessary consequence of the 2d. Principle of thermodynamics which prescribes an irreversible increase of general entropy with time. However (and paradoxically) complex systems become highly organized by creating heterogeneous structures through dissipation of growing quantities of energy obtained from their environment, but at the price of rejecting more entropy in this same environment.

This type of situations has been clarified by PRIGOGINE, within the frame of his thermodynamics of irreversible systems