Intelligent design is the proposition that certain features of the universe and living things are best explained by an intelligent cause rather than by undirected natural processes such as mutation and natural selection. Proponents argue that this conclusion can be reached through observation of the natural world using the ordinary methods of science, without recourse to scripture or religious doctrine. Critics describe intelligent design as a form of creationism reframed to avoid legal and educational restrictions on teaching religious doctrine in public schools; this dispute over the proper characterization of intelligent design is treated in intelligent-design-classification-debate.

Intelligent design arguments center on two principal concepts: “irreducible complexity,” the claim that some biological systems cannot have evolved through gradual natural selection because their components have no function unless all are present simultaneously, and “specified complexity,” a probabilistic argument that certain patterns are too improbable to arise by chance and too specified to result from natural law alone. Proponents point to molecular structures such as the bacterial flagellum and the blood-clotting cascade as candidate examples, and some also invoke the fine-tuning of physical constants in cosmology as evidence of design.

The mainstream scientific community has rejected these arguments, holding that the cited biological examples can be explained by known evolutionary mechanisms and that intelligent design does not generate testable predictions or function as a research program within biology. Intelligent design proponents dispute this characterization and maintain that detection of design is amenable to scientific methodology. The 2005 federal court decision in *Kitzmiller v. Dover Area School District* found that intelligent design is not science and is religious in nature, a contested ruling; see intelligent-design-kitzmiller-controversy.

There is broad agreement among biologists, geologists, and other relevant scientists, arrived at independently across institutions and countries, that evolution by natural selection adequately accounts for the diversification of life without requiring an intelligent designer. See Evolution - Biological Science Consensus.

• Intelligent design proponent viewpoint - holds that the complexity of certain biological and cosmological features is best explained by an intelligent cause, detectable through scientific reasoning. See intelligent-design-proponent-viewpoint.
• Mainstream scientific viewpoint - holds that intelligent design lacks empirical support, makes no testable predictions, and is not a scientific theory but a religiously motivated argument. See intelligent-design-mainstream-scientific-viewpoint.
• Theistic evolution viewpoint - holds that evolution by natural selection is the accurate scientific account of life's history and is compatible with belief in a creator who works through natural processes rather than discrete interventions. See intelligent-design-theistic-evolution-viewpoint.
• Young-earth creationist viewpoint - accepts some intelligent design arguments against evolutionary mechanisms but holds that they do not go far enough, advocating instead for a literal biblical account of a young earth and special creation; closely associated with organizations such as Answers in Genesis. See young-earth-creationism-viewpoint.
• Religious dissent viewpoint - encompasses religious believers and theologians who reject intelligent design on theological rather than scientific grounds, arguing it represents poor theology or an unnecessary “god of the gaps.” See intelligent-design-religious-dissent-viewpoint.

• The *Kitzmiller v. Dover* trial and its aftermath remain a focal point of dispute over whether intelligent design may be taught in American public schools. See intelligent-design-kitzmiller-controversy.
• The 2008 documentary *Expelled: No Intelligence Allowed* and the broader “academic freedom” movement generated controversy over claims that intelligent design proponents face professional discrimination. See intelligent-design-expelled-controversy.

• History: intelligent-design-history
• Debate: intelligent-design-classification-debate
• Viewpoint Debate: intelligent-design-proponent-mainstream-scientific-viewpoint-debate
• Consensus: Evolution - Biological Science Consensus
• Controversy: intelligent-design-kitzmiller-controversy
• Related Main Topics: Science and Religion, Young Earth Creationism, Heliocentrism - Religious Dissent Viewpoint

1. William A. Dembski, *The Design Inference: Eliminating Chance through Small Probabilities* (Cambridge: Cambridge University Press, 1998).
2. Michael J. Behe, *Darwin's Black Box: The Biochemical Challenge to Evolution* (New York: Free Press, 1996).
3. Kenneth R. Miller, *Finding Darwin's God: A Scientist's Search for Common Ground between God and Evolution* (New York: Cliff Street Books, 1999).
4. *Kitzmiller v. Dover Area School District*, 400 F. Supp. 2d 707 (M.D. Pa. 2005).
5. Barbara Forrest and Paul R. Gross, *Creationism's Trojan Horse: The Wedge of Intelligent Design* (Oxford: Oxford University Press, 2004).