Proponents of two axioms of biological evolutionary theory have attempted to find justification by reference to nonequilibrium thermodynamics. One states that biological systems and their evolutionary diversification are physically improbable states and transitions, resulting from a selective process; the other asserts that there is an historically constrained inherent directionality in evolutionary dynamics, independent of natural selection, which exerts a self-organizing influence. The first, the Axiom of Improbability, is shown to be nonhistorical and thus, for a theory of change through time, (...) acausal. Its perception of the improbability of living states is at least partially an artifact of closed system thinking. The second, the Axiom of Historically Determined Inherent Directionality, is supported evidentially and has an explicit historical component. Historically constrained dynamic populations are inherently nonequilibrium systems. It is argued that living, evolving systems, when considered to be historically constrained nonequilibrium systems, do not appear improbable at all. Thus, the two axioms are not compatible. Instead, the Axiom of Improbability is considered to result from an unjustified attempt to extend the contingent proximal actions of natural selection into the area of historical, causal explanations. It is thus denied axiomatic status, and the effects of natural selection are subsumed as an additional level of constraint in an evolutionary theory derived from the Axiom of Historically Determined Inherent Directionality. (shrink)

The basic features of thermodynamics as the “science of the possible” are outlined with a special emphasis on the role of the concept of entropy as a measure of irreversibility in natural processes and its relation to “order,” precisely defined. Natural processes may lead to an increase in complexity, and this concept has a subtle relationship to those of order, organization, and information. These concepts are analyzed with respect to their relation to biological evolution, together with other ways of attempting (...) to quantify it. Thermodynamic interpretations of evolution are described and critically compared, and the significance of dissipative structures, of “order through fluctuations,” is emphasized in relation both to the evolutionary succession of temporarily stable forms and to kinetic mechanisms producing new patterns. (shrink)