Teleological and teleonomic: a new analysis

Teleological language is frequently used in biology in order to make statements about the functions of organs, about physiological processes, and about the behavior and actions of species and individuals. Such language is characterized by the use of the words ‘function’, ‘purpose’, and ‘goal’, as well as by statements that something exists or is done ‘in order to’. Typical statements of this sort are ‘It is one of the functions of the kidneys to eliminate the end products of protein metabolism’, or ‘Birds migrate to warm climates in order to escape the low temperatures and food shortages of winter’. In spite of the long-standing misgivings of physical scientists, philosophers, and logicians, many biologists have continued to insist not only that such teleological statements are objective and free of metaphysical content, but also that they express something important which is lost when teleological language is eliminated from such statements. Recent reviews of the problem in the philosophical literature (Nagel, 1961; Beckner, 1969; Hull, 1973; to cite only a few of a large selection of such publications), concede the legitimacy of some teleological statements but still display considerable divergence of opinion as to the actual meaning of the word ‘teleological’ and the relations between teleology and causality.