Teleology

Teleology (telos: end, purpose) is the philosophical study of design, purpose, directive principle, or finality in nature or human creations.

Contrasted with philosophical naturalism
Teleology traditionally is contrasted with philosophical naturalism, which views nature as lacking design or purpose. For example, naturalism would say that a person has sight simply because they have eyes. In other words, function follows form (eyesight follows from having eyes). Teleology is the reverse of this position: a person has eyes because they have the need of eyesight. In this case, form follows function (eyes follow from having the need for eyesight).

Two classic examples of these opposing views are found in Aristotle and Lucretius, the former as a supporter of teleology and the latter as a supporter of what is now called philosophical naturalism:

Extrinsic and intrinsic finality
Teleology depends on the concept of a final cause or purpose inherent in all beings. There are two types of such causes, intrinsic finality and extrinsic finality.
 * Extrinsic finality consists of a being realizing a purpose outside said being, for the utility and welfare of other beings. For instance, minerals are "designed" to be used by plants which are in turn "designed" to be used by animals.
 * Intrinsic finality consists of a being realizing a purpose by means of a natural tendency directed toward the perfection of its own nature. In essence, it is what is "good for" a being.  For example, physical masses obey universal gravitational tendencies that did not evolve, but are simply a cosmic "given."  Similarly, life is intended to behave in certain ways so as to preserve itself from death, disease, and pain.

Over-emphasizing extrinsic finality is often criticized as leading to the anthropic attribution of every event to God's will, and mere superstition. For instance, "If I hadn't been at the store today, I wouldn't have found that $100 on the ground. God must have intended for me to go to the store so I would find that money." Such abuses were criticized by Francis Bacon ("De Dignitate et Augmentis Scientiarum," III, iv), Descartes ("Principia Philosophiæ", I, 28; III, 2, 3; "Meditationes", III, IV), and Spinoza (Ethica, I, prop. 36 app.).

Intrinsic finality, while more subtle, provides the basis for the teleological argument for the existence of God, and its modern counterpart, intelligent design. Proponents of teleology argue that it resolves a fundamental defect in philosophical naturalism. They argue that naturalism focuses exclusively on the immediate causes and mechanisms of events, and does not attend to the reason for their synthesis. Thus, it is argued, if we take a clock apart, we discover in it nothing but springs, wheels, pivots, levers etc. But having explained the mechanism which causes the revolutions of the hands on the dial, is it reasonable to say that the clock was not made to keep time?

Classical Greek teleology
Plato summarized the argument for teleology as follows in Phaedo, arguing that it is error to fail to distinguish between the ultimate Cause, and the mere means by which the ultimate Cause acts:
 * "Imagine not being able to distinguish the real cause from that without which the cause would not be able to act as a cause. It is what the majority appear to do, like people groping in the dark; they call it a cause, thus giving it a name that does not belong to it. That is why one man surrounds the earth with a vortex to make the heavens keep it in place, another makes the air support it like a wide lid. As for their capacity of being in the best place they could possibly be put, this they do not look for, nor do they believe it to have any divine force, but they believe that they will some time discover a stronger and more immortal Atlas to hold everything together more, and they do not believe that the truly good and "binding" binds and holds them together." (Plato, Phaedo 99bc)

Thus, it is argued, those who attempt to explain nature in terms of nature alone are forced to deny the ultimate binding Good (or other such invisible forces, such as gravity and electromagnetism) in the universe, and hope that they will someday discover a stronger supporting argument ("Atlas" or, for example, God) to hold their universe together.

Similarly, Aristotle argued that it is error to attempt to reduce all things to mere necessity, because such thinking neglects the purpose, order, and final cause that causes the apparent necessity. He wrote:
 * "Democritus, however, neglecting the final cause, reduces to necessity all the operations of nature. Now they are necessary, it is true, but yet they are for a final cause and for the sake of what is best in each case. Thus nothing prevents the teeth from being formed and being shed in this way; but it is not on account of these causes but on account of the end; these are causes in the sense of being the moving and efficient instruments and the material. …to say that necessity is the cause is much as if we should think that the water has been drawn off from a dropsical patient on account of the lancet alone, not on account of health, for the sake of which the lancet made the incision." Aristotle, Generation of Animals V.8, 789a8-b15

Modern/postmodern philosophy
The area in which, within modern philosophy, teleology has had a powerful influence right through to the present has been in Hegel and the various neo-Hegelian schools, including that of Marx. In this interpretation of the history of our species on this globe — an interpretation at variance both with Darwin and with what is now called analytic philosophy — the point of departure is not so much formal logic and scientific fact but 'identity'. (In Hegel's terminology: 'objective spirit'.) Individual human consciousness, in the process of reaching for autonomy and freedom, has no choice but to deal with an obvious reality: the collective identities (the multiplicity of world views, ethnic, cultural and national identities) which divide the human race both now and in the past, and which set off (and always have set off) different groups of people against each other in violent conflict. Hegel conceived of the 'totality' of mutually antagonistic world-views and life-forms in history as being 'goal-driven', i.e. oriented towards an end-point in history in which the 'objective contradiction' of 'subject' and 'object' would eventually 'sublate' into a form of life which has left violent conflict behind it. This goal-oriented, 'teleological' notion of the 'historical process as a whole' is present in a variety of 20th Century authors, from Lukács to Horkheimer and Adorno.

According to Jean-François Lyotard (1979) teleology and "grand narratives" are eschewed in a postmodern attitude. Teleology may be viewed as reductive, exclusionary and harmful to those whose stories are erased.

Science
In recent decades, a form of teleological reasoning has reappeared in certain quarters of physics and cosmology, under the heading of anthropic principle, a term Brandon Carter coined in 1973. The problem the anthropic principle tries to address is: Why did the universe begin in a very simple state (Big Bang) but has since grown ever more complex, to the extent that, at least in our corner of it, it is hospitable to life as complex as homo sapiens?

For a very detailed discussion of this resurgence of teleology in natural science, see Barrow and Tipler (1986). While long stretches of this monograph are technically challenging, it also includes: Barrow and Tipler include many references. Teleological considerations also inform some of the writings of Arthur Eddington, Freeman Dyson, and John Wheeler.
 * A circa 200pp masterly review of much of the intellectual history of teleology and design arguments. Here the authors draw attention to the distinction, drawn by L. E. Hicks in 1883 and since ignored, between teleology and eutaxiology;
 * A whole chapter on the teleological implications of earth science and chemistry, with special reference to the eclectic but little known work of Lawrence Joseph Henderson;
 * A fair discussion of the implications of evolutionary biology for teleology, granting pride of place to the writings of Theodosius Dobzhansky and Ernst Mayr;
 * Teleological speculations on the ultimate fate of the universe.

Contemporary accounts of teleology within biology are heavily influenced by Larry Wright's "etiological" account of teleology. Wright's sought to supply a definition of "function" that could be applied to natural phenomena as well as human artifacts - that is, human constructions such as a hammer. Most contemporary accounts of teleology follow in the steps of Wright's etiological account (Millikan for instance). There is, however, disagreement over its use. Some, such as Godfrey-Smith and Ernst Mayr, object to any sort of etiological theory of teleology that attempts to explain both natural phenomena as well as human artifacts. Their accounts therefore are therefore naturalistic accounts of teleology.

Technology
Teleology has a long history in the study of purpose in human creations such as technology. The study of "teleological mechanisms" in machinery (i.e. machines with corrective feedback) dates back at least to the late 1700s when James Watt's steam engine was equipped with a governor.

More recently, Julian Bigelow, Arturo Rosenblueth, and Norbert Wiener conceived of teleology in machinery as being a feedback mechanism. Wiener, a mathematician, coined the term 'cybernetics' to denote the study of "teleological mechanisms," which was popularized through his book Cybernetics, or control and communication in the animal and machine (1948). Cybernetics is the study of the communication and control of regulatory feedback, both in living beings and machines, and in combinations of the two. Since that time the term "teleologic" in particular has been frequently used in the scientific literature to capture the sense of purposeful goal-directed behavior in biological and technological control systems.