The theory of intelligent design (ID) holds that life and living things show signs of having been designed. ID's primary argument is that life is too complex to have simply "happened."
Advocates of ID believe there is empirical evidence that an Intelligent Designer has been at work in the history of life, and that macroevolution of life, and particularly the evolution of humans, has been guided by that Designer. Members of the "intelligent design movement" are typically Christians (primarily Evangelicals, plus one prominent Unificationist), but ID itself does not specify the identity of the Designer.
Much of the controversy over ID stems from the desires of its advocates to get the theory accepted as a scientific hypothesis—a desire which has consistently been thwarted by the scientific establishment.
The basic ID argument is similar to the argument from design presented by William Paley in his book Natural Theology, published in 1800. Charles Darwin reported being deeply influenced by Paley's book—required reading in his time—which he later rejected based on the evidence at hand. Today the global scientific community overwhelmingly accepts and applies the theory of evolution (See also natural selection.) originated by Charles Darwin and updated by many. Intelligent design has been unable to penetrate a single peer-reviewed scientific journal.
Opponents of ID often argue that it is part and parcel of creationism. Proponents put forth several differences. The theory does not argue for (or against) Biblical inerrancy, it allows that the Designer(s) could be Little Green Men, and it does not contest the experimentally established fact of evolution within "kinds" or genera. Not all creationists find those views compatible with theirs, but many do. Most ID proponents accept the scientific evidence fixing the age of the Earth at about 4.6 billion years, compatible with Old Earth Creationism, while others are Young Earth Creationistss. The godfather of the ID movement, University of California, Berkeley law professor Phillip E. Johnson (now emeritus), is quoted as saying that issues such as the age of the earth can be taken up once the common enemy of evolution has been done away with. This is often interpreted by both creationists and their opponents to mean it is merely a tactical device.
Opponents of ID accuse it of existing only as a disguise to try to sneak creationism into school science textbooks while evading the Establishment Clause of the U.S. Constitution. Proponents insist that it is a scientific (or, perhaps more accurately, philosophical) theory, and is not connected to any specific religion.
A key objection to ID is that it does not explain where the Intelligent Designer comes from. Opponents of ID say that instead of explaining the complexity of life, it merely transfers the problem to an unknown domain where it cannot be directly analyzed, since now explanations have to cover a newly introduced alien or supernatural entity while evolution does not need to. Using the ID standard for evidence of design, any designer would appear to be designed, so what designed the Designer?
ID accepts that there has been microevolution, i.e., populations of species have changed and diverged over time. It may or may not accept that there is speciation, the creation of more than one species out of a single species. Some proponents of ID accept the fossil record as an accurate representation of the history of the evolution of species, and accept that analysis of the fossil record gives accurate and useful results; others do not.
It accepts that there is a process of natural selection, although it may insist that the results of this process must be limited. Once the variation has been caused due to deliberate acts of God, or the unnamed intelligent designer, the survival or extinction of a newly arisen species is believed to then be subject to natural selection, although further acts of God are not ruled out.
According to the theory of evolution, genetic variations occur randomly, and environmental stress selects against those variations that are not as advantageous as others. In the Intelligent Design viewpoint, these random variations exist but are not the explanation for the appearance of new "kinds." The definition of a "kind" is vague, usually something like a genus rather than a species. For creationists, it should allow room on Noah's Ark for a pair of each kind. New kinds arise when The Designer steps in and causes significant variation to occur. Actually, ID is not closely tied to "kinds," but to complex changes whenever they occur.
Adherents of Intelligent Design call the idea that God causes new species to come into being a viable scientific hypothesis (see scientific creationism). Nearly all scientists consider it pseudo-scientific, on the grounds that it is an amalgam of false or unsupported claims within the realm of science, and of philosophical or religious claims outside the realm of science. (See methodological naturalism for a discussion of supernatural explanations in science.)
To underscore the pseudo-scientific nature of ID, in the mid-1990s George W. Gilchrist of the University of Washington looked through thousands of scientific journals searching for any articles on intelligent design or creation science—he didn't find any. Other more recent surveys have also failed to find articles on these subjects in the primary scientific literature (not to mention that only a handful of these articles were even submitted). ID proponents claim this is due to a global conspiracy, career requirements, etc. In response, opponents can point out that tenured professors are pretty safe, and anyone presenting convincing evidence of design would be lavishly rewarded and published in the popular press. In contrast, many articles have been published in highly-ranked journals which specifically deny the claims of ID (for example, Lenski et al. 2003 The evolutionary origin of complex features. Nature 423:139-44.)
Advocates of intelligent design argue that the biological evidence presents serious problems for macroevolution. For example, they claim that all the major types of animals appeared at the same time in the fossil record with no evidence of common ancestry (a claim that is not supported by subject experts)—a pattern they say is inconsistent with Darwin's theory of evolution. Modern evolutionary biologists' concept of evolution goes beyond the gradualism proposed by Darwin in the nineteenth century. Better evidence gathered since the time of Darwin has shown that evolution occurs at a steady Darwinian rate until a large environmental change occurs (such as an ice age, asteroid impact, or very large volcanic eruption). Evolution then occurs at a greatly accelerated rate. Those who adhere to the concept of intelligent design seem to ignore the modern concept of evolution, say many scientists.
They also argued that complex organs that cannot function without all their parts provide evidence for a cause having intelligence. Usually, this intelligence is attributed to God. This is one aspect of the idea that some biological developments are too complex to have come about without having been designed. This idea is particularly pressed by Michael Behe under the rubric irreducible complexity in his Darwin's Black Box (1996; see reference above). See also: argument from design and especially argument by lack of imagination. This is also called a "God in the gaps" argument. All of Behe's examples have been explained without the need for design (an example).
Proponents of Intelligent Design point to complex biological structures such as the eye, birds' wings, the existence of mitochondria, bacterial flagella, etc., arguing that such structures could not possibly have developed due purely to random mutations, even with the aid of natural selection. Symbiotic relationships, such as plants which can only be pollinated by a specific species of insect, which in turn can only reproduce by using the plant, could not have arisen, they argue—a typical chicken and egg problem. It is argued that these kinds of biological features are by their very nature too interdependent to come into existence independently through a natural process and then become so intricately intertwined. Opponents say these examples have been adequately explained.
The criticism of Intelligent Design is based on looking at certain examples, often the same ones as ID proponents use.
Most of Intelligent Design's examples of things that cannot be explained by evolution have since been explained by new advances in genetics and biotechnology. For example, the development of mitochondria was once puzzling, but Lynn Margulis's theory of their evolution from endosymbiotic bacteria,
once rejected even by biologists, has amassed enough evidence that it is now widely accepted.
Critics of ID say that evolutionary development of such structures as eyes and wings has been simulated in computers. Studies of fig wasps have revealed how symbiotic species can evolve.
A particularly famous example of an argument for ID is 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 an intelligent designer because they are too complex to work half-evolved.
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.
Many early creationists cited the human eye as their prime example of this principle; "What use is half an eye?", they asked. Evolutionists would provide a detailed 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 proof by both creationists and intelligent design proponents that a higher power must be responsible for creating such a complex organ. Scientists, however, have devised working hypotheses on how certain body parts and organs 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 half an 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 (this has happened at least twice in evolution with the advent of the cephalopod eye and is currently under way with many other animal groups). Each of these steps 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 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. There is no need for divine intervention of intelligent design, say scientists.
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.
Further, say scientists, a body part or organ that has a modern function did not necessarily have the same function in the past. Evolution works on chance and opportunity, with gill bones of mouth-less fishes evolving into jaws, fish air bladders becoming vertebrate lungs, and fin support structures becoming fingers and toes. Scientists have also argued that arguments like the watch argument actually damage the case for the ID theory. Specifically, some of them claim that life is often "poorly designed" on the macroscopic, cellular, and genetic levels. Other just say that we just don't have enough knowledge about the processes in living systems to draw this type of conclusion.
Some people use the term "intelligent design" in a broader sense than that given in Intelligent Design Theory. It can refer simply to the belief that God designed the universe, without any specific claim as to how or when he did so. Many people consider this belief entirely compatible with standard Darwinian evolution, with no divine intervention—life could be produced by a purely natural process, evolution, designed by God. God might merely have written the laws of physics, or chosen the fundamental constants, and left the universe to run like clockwork afterwards. This would be a form of deism. The belief that the laws of the universe were constructed to allow for the existence of intelligent life is known as the Anthropic Cosmological Principle. A more theologically robust view is theistic evolution (see e.g. Kenneth R. Miller's "Finding Darwin's God" cited above), which is too nuanced to explain here. Not all people who believe God was involved in the design of the Universe also adhere to the specifics of the Intelligent Design belief, as proposed by Creationists.
Intelligent Design has lately been a controversial subject, particularly in American schools. After years of judicial rejection of Creationist teaching—on the grounds that Creationism is a religious theory, not a scientific theory—many Creationists have begun to promote Intelligent Design as a non-religious, scientifically acceptable alternative to the theory of Evolution. However, this attempt has met with strong opposition from some
theologians. In order to be non-religious, one must argue that the
intelligent being who designed the universe is not necessarily the same
as the religious God. This view has been criticized as allowing for the
existence of a demiurge and for being perilously close to Gnosticism, which is considered heretical by most Christian groups.
Intelligent Design and the Theory of Evolution
Evolutionary vs. ID views
Criticism of Intelligent Design
The watch argument
The Eye Argument
Additional arguments
Broader view of "intelligent design"
Public discourse
See also
Further Reading
External links
