Teleonomy is the quality of apparent purposefulness and of goal-directedness of structures and functions in living organisms brought about by natural processes like natural selection. The term derives from two Greek words, τέλος, from τελε-, ("end", "goal", "purpose") and νόμος nomos ("law"). Teleonomy is sometimes contrasted with teleology, where the latter is understood as a purposeful goal-directedness brought about through human or divine intention. Teleonomy is thought to derive from evolutionary history, adaptation for reproductive success, and/or the operation of a program. Teleonomy is related to programmatic or computational aspects of purpose.
Relationship with teleology
Colin Pittendrigh, who coined the term in 1958, applied it to biological phenomena that appear to be end-directed, hoping to limit the much older term teleology to actions planned by an agent who can internally model alternative futures with intention, purpose and foresight:
In 1965 Ernst Mayr cited Pittendrigh and criticized him for not making a "clear distinction between the two teleologies of Aristotle"; evolution involves Aristotle's material causes and formal causes rather than efficient causes. Mayr adopted Pittendrigh's term, but supplied his own definition:
Richard Dawkins described the properties of "archeo-purpose" (by natural selection) and "neo-purpose" (by evolved adaptation) in his talk on the "Purpose of Purpose". Dawkins attributes the brain's flexibility as an evolutionary feature in adapting or subverting goals to making neo-purpose goals on an overarching evolutionary archeo-purpose. Language allows groups to share neo-purposes, and cultural evolution - occurring much faster than natural evolution - can lead to conflict or collaborations.
In behavior analysis, Hayne Reese made the adverbial distinction between purposefulness (having an internal determination) and purposiveness (serving or effecting a useful function). Reese implies that non-teleological statements are called teleonomic when they represent an "if A then C" phenomenon's antecedent; where, teleology is a consequent representation. The concept of purpose, as only being the teleology final cause, requires supposedly impossible time reversal; because, the future consequent determines the present antecedent. Purpose, as being both in the beginning and the end, simply rejects teleology, and addresses the time reversal problem. In this, Reese sees no value for teleology and teleonomic concepts in behavior analysis; however, the concept of purpose preserved in process can be useful, if not reified. A theoretical time-dimensional tunneling and teleological functioning of temporal paradox would also fit this description without the necessity of a localized intelligence. Whereas the concept of a teleonomic process, such as evolution, can simply refer to a system capable of producing complex products without the benefit of a guiding foresight.
In 1966 George C. Williams approved of the term in the last chapter of his Adaptation and Natural Selection; a critique of some current evolutionary thought. In 1970, Jacques Monod, in Chance and Necessity, an Essay on the Natural Philosophy of Modern Biology, suggested teleonomy as a key feature that defines life:
In 1974 Ernst Mayr illustrated the difference in the statements:
:: "The Wood Thrush migrates in the fall in order to escape the inclemency of the weather and the food shortages of the northern climates."
:: "The Wood Thrush migrates in the fall and thereby escapes the inclemency of the weather and the food shortages of the northern climates."
Subsequently, philosophers like Ernest Nagel further analysed the concept of goal-directedness in biology and by 1982, philosopher and historian of science David Hull joked about the use of teleology and teleonomy by biologists:
Relationship to evolution
The concept of teleonomy was largely developed by Mayr and Pittendrigh to separate biological evolution from teleology. Pittendrigh's purpose was to enable biologists who had become overly cautious about goal-oriented language to have a way of discussing the goals and orientations of an organism's behaviors without inadvertently invoking teleology. Mayr was even more explicit, saying that while teleonomy certainly operates on the level of organisms, the process of evolution itself is necessarily non-teleonomic.