b) Teleology in Biology

Does evolution call for a teleological explanation? Some scholars have found a middle-ground between two extremes: evolution as purposeless, governed entirely by blind chance and evolution as the result of a detailed and pre-conceived design. According to Ayala’s functionalist interpretation,biological structures, organs, and behaviors are teleological if they are adaptations, that is, if they arose through natural selection because the function they serve increases reproductive success. Such teleological explanations are fully compatible with efficient causal explanations --- indeed, in some cases both are required. William Stoegerargues for teleology, or at least directionality, in evolution in the sense that, for a particular configuration at a given moment, only a certain range of configurations at successive moments are possible. He also situates evolutionary directionality in the broader context of cosmology, astronomy, and self-organization. Paul Daviesexplores the roles of self-organization and emergent complexity in neo-Darwinian evolution as suggesting “teleology without teleology.” Arthur Peacocke draws on B. B. Simpson and Karl Pepper in claiming that there are “propensities” for properties like complexity and information-processing which characterize the gradual evolution of complex organisms.

Wesley Wildmanhas exposed the difficulty in arguing directly from functional or apparent ends in nature to a philosophy of nature that includes genuine teleological principles and a metaphysics capable of supporting them. Moreover, there are profound teleological visions that are antagonistic towards, or at least not amendable to, theism and are equally well supported by evolution. He notes, however, that an argument from teleology to ends is quite possible. Some scholars have taken the latter approach, arguing that without an adequate metaphysics we cannot include the categories of sentience, such as perception, mentality, and purpose, in our scientific explanation of the evolution of life. For Charles Birch,John Haught, and Ian Barbour,Whiteheadian metaphysics is the most helpful; Birch is particular argues for purpose in nature.Finally George Ellisis critical of those who argue for “blind chance” against any form of teleology. Typically they ignore their own epistemological and metaphysical assumptions, and they take for granted the underlying laws of physics which make evolution possible, even though these laws raise questions of design at a cosmological level.

Contributed by: Dr. Robert Russell