Rhapsodic Evolution: Essay on Exaptation and Evolutionary Pluralism

Since formulating the theory of punctuated equilibria in 1972, a group of prominent evolutionary biologists, geneticists, and paleontologists have contributed towards a significant reinterpretation of the neo-Darwinian image of evolution that had consolidated during the second half of the twentieth century. We believe a research program, which we might define as "evolutionary pluralism" or "post-Darwinism," has been outlined, one that is centered on the discovery of the complexity and multiplicity of elements that work together to produce changes in our evolutionary systems. We are talking about a three-dimensional multiplicity: a multiplicity of rhythms in evolution (i.e., the theory of punctuated equilibria); a multiplicity of evolutionary units and levels (i.e., the hierarchical theory of evolution); and a multiplicity of factors and causes in evolution (i.e., the concept of exaptation). Although the reductionistic and deterministic view of natural history interprets the intelligence of evolution as a panoptic and executory rationality, evolutionary pluralism, going back to the original flexibility of the Darwinian opus, sees in the intelligence of evolution an ingenious m tis, an imperfect but very creative, craftsmanlike cleverness. The new metaphors of change introduced by evolutionary pluralism and the consequent criticism of the adaptational paradigm offer some very interesting spin-offs for the study of evolutionary systems in widely differing fields, from theoretical economics to the cognitive sciences. I propose a particular hypothesis concerning the possibility and usefulness of expanding the concept of exaptation into a general theory of developmental processes, both in biology as well as in the cognitive sciences.