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A teleological argument (or an argument from design) is an argument for the existence of God based on evidence of design in nature. Although there are variations, the basic argument goes something like this:
- Premise 1: X was intelligently designed,
- Premise 2: X was not designed by humans.
- Premise 3: The only conceivable beings capable of intelligent design are humans (who exist) and God (who may or may not exist).
- From (3): The only conceivable beings capable of designing X in particular are humans (who exist) and God (who may or may not exist).
- Recall (2): that X was not designed by humans.
- If God doesn't exist, then X was also not designed by God.
- Thus if God doesn't exist, then none of the conceivable beings capable of designing X designed X, in which case X was not designed at all.
- Since God not existing therefore results in a contradiction of (1), God must exist.
X usually stands either for the whole universe, the evolution process, human kind, a given animal species or for a particular organ (e.g., the eye) or capability (e.g., language in humans). It can also stand for the fundamental constants of the universe, based on the anthropic principle that these constants seem specially tuned to allow intelligent life to evolve.
Although the second premise is widely accepted, the third premise, and especially the first premise, are disputed.
In the 19th century this argument as presented by William Paley formed an important part of the doctrine of the Church of England. Teleological arguments for the existence of God are put forward today by many people, particularly in Iran and the United States, who consider that this gives scientific support for their faith. The same argument is at the core of the theory of Intelligent Design. Their opponents claim that such arguments are not scientific as they fail to meet the criteria of scientific philosophy, particularly falsifiability and naturalism.
The first premise assumes that one can infer the existence of intelligent design, merely from examining the designed object. This belief forms the basis of, for example, the Search for Extra_Terrestrial Intelligence, which attempts to determine whether electromagnetic radiation is the result of a natural process, or the intelligent design of an alien race. This is related to the sometimes ignored fact that any sufficiently large random sequence has patterns, so the existence of patterns does not mean that the whole universe is non-random.
Simplistic forms of the teleological argument assume that because life is complex, therefore it must have been designed. Some characterise this approach as an argument from ignorance.
Stronger forms rely on the concepts such as irreducible complexity, which was proposed by Michael Behe.
Most professional biologists support the theory of biological evolution by means of natural selection. They reject the first premise, arguing that evolution is not only an alternative explanation for the complexity of life but a better explanation. Thus they tend to view the teleological argument as a poor argument for the existence of a god.
Some argue that, even if the argument correctly implies the existence of a non-human artificer (i.e., if the first and second premise are accepted), that artificer might not be God, as God is commonly understood. For example, it could have been an alien civilization from another world.
Although the third premise appears to be the most embattled portion of the argument, refutations have also been tried along other grounds. One approach is a proof by reductio ad absurdum.
- Premise 1: The teleological argument is sound (assumption for reductio)
- Therefore: An intelligent designer exists.
- Premise 2: The teleological argument applies to the intelligent designer, for the designer must be at least as complex and purposeful as the designed object
- Therefore: An intelligent designer of the intelligent designer exists.
- Similarly: An infinite chain of intelligent designers exists.
- Premise 3: An infinite chain of intelligent designers does not exist, for this is absurd.
- Conclusion: one of the three premises is false.
See also: first cause
Cicero made one of the earliest teleological arguments, by means of a timepiece:
- When you see a sundial or a water-clock, you see that it tells the time by design and not by chance. How then can you imagine that the universe as a whole is devoid of purpose and intelligence, when it embraces everything, including these artifacts themselves and their artificers? (Gjertsen 1989, p. 199, quoted by Dennett 1995, p. 29)
David Hume presented arguments both for and against the teleological argument in his Dialogues Concerning Natural Religion. The character Philo, summarizing the teleological argument, uses an example of a watch. Philo is not satisfied with the teleological argument, however, and attempts a number of interesting refutations, including one that arguably foreshadows Darwin's theory. In the end, however, Hume has Philo agree that the teleological argument is valid. (Dennett 1995, p. 29) Daniel Dennett (ibid.) claims that, although Hume was ultimately dissatisfied with the teleological argument, his cultural context prevented him from taking any of the alternatives seriously. (As it happens, during the Voyage of the Beagle Darwin was given the nickname of Philos when he took over the duties of ship's naturalist after the ship's surgeon left the ship.)
The most famous proponent of the teleological argument is William Paley (1743-1805), who also framed the argument with reference to a watch in his Natural Theology.
The watch argument
In 1802 theologian William Paley wrote that if a pocket watch is found on a field, it is most reasonable to assume that someone dropped it and that it was made by a watchmaker and not by natural forces. Paley went on to argue that complex structures of living things must be the work of God. One theology student who found these arguments compelling was Charles Darwin who later developed his theory of the Origin of Species by Means of Natural Selection which put forward an alternative explanation for complexity in nature.
Many have attempted to refute Paley's argument, mainly by showing that highly complex systems can be produced by a series of very small randomly-generated steps. Richard Dawkins' book The Blind Watchmaker is one of the best known works following this idea.
The debate over this is closely related to irreducible complexity, the idea that certain structures in biology can function only if all their substructures are present. It is argued that each substructure confers no benefit on its own, and therefore would not have been selected by an evolutionary mechanism. The probability of all the substructures being created in a single mutation is too low to be considered possible.
The eye argument
Many creationists cite the eye as a prime example of this principle; "What use is a partly-developed eye?", they asked. Evolutionists would provide an explanation for this and would state that creationists were simply falling into the logical fallacy called lack of imagination. A modern explanation for the evolution of the eye is given here.
The apparent "miracle" of the human eye, along with other body parts and organs, has often been used as evidence by both creationists and intelligent design proponents that a higher power or designer must be responsible for creating such a complex organ. Scientists, however, have devised working hypotheses on how certain body parts and organs could have evolved.
For example, many biological cells not associated with the senses respond to the presence of light. Most notable of this group are photosynthetic cells of algae and plants. Other very primitive organisms have very rudimentary photoreceptive cells that can only tell the difference between light and dark. These organisms use this primitive sense to orient themselves correctly toward light. In other words, much less than a complete eye is actually quite useful. Yet other organisms have clusters of these photoreceptive cells that can distinguish crude shapes. Increasing the complexity, number, and arrangement of these cells will then yield rudimentary eyes that can recognize certain objects by shape and so on until an eye capable of seeing in color and three dimensions is produced (according to evolutionists, this has happened at least twice with the advent of the cephalopod eye and is currently under way with many other animal groups). Each of these states in the development of a fully functioning eye has modern analogues in the animal kingdom, and each step need only develop through nothing more than mutations and natural selection: those animals with a better ability to sense their environment with photoreceptive cells will survive to produce more young than those that don't have this ability, and so on. Evolutionists thus claim there is no need for divine intervention of intelligent design.
Richard Dawkins in particular has vigorously challenged ID arguments similar to Paley's. Furthermore, he points out that a hypothetical evolutionary path such as that given above for the eye need not even be correct; in order to refute the argument from design it need only be plausible, thus demonstrating that there are other ways in which such an organ could have come about. The title of Dawkins' book The Blind Watchmaker is a reference to Paley's example of the pocket watch. Dawkins's book, River out of Eden (1995) gives an example of a computer simulation where multiple independent organisms all showed a steady progression from a light-sensitive spot to a complex eye with a lens focus.
Creationists counter that each step in this alleged process is itself actually a huge leap. For example, the explanation has gone from no light sensitivity at all, to cells that can sense the presence of light, send a signal regarding that to the brain, and processes in the brain to translate that into instructions to muscles that operate to orient the organisms towards the light.
- Dictionary of the history of Ideas: (http://etext.lib.virginia.edu/cgi-local/DHI/dhi.cgi?id=dv1-80) Design argument
- William Paley. Natural Theology; or, Evidences of the Existence and Attributes of the Deity (http://www.hti.umich.edu/cgi/p/pd-modeng/pd-modeng-idx?type=header&id=PaleyNatur), London: 12th edition, 1809. Online in full.
- Design arguments for the existence of God (http://www.iep.utm.edu/d/design.htm) from the Internet encyclopedia of philosophy.
References and further reading
See also: Design