Intelligent design (ID) is the proposition that "certain features of the universe and of living things are best explained by an intelligent cause, not an undirected process such as natural selection." It is a form of creationism and a contemporary adaptation of the traditional teleological argument for the existence of God, presented by its advocates as "an evidence-based scientific theory about life's origins" rather than "a religious-based idea". It avoids specifying that the hypothesized intelligent designer is God. Its leading proponents are associated with the Discovery Institute, a politically conservative think tank, and believe the designer to be the Christian God.
ID seeks to redefine science in a fundamental way that would invoke supernatural explanations, a viewpoint known as theistic science. It puts forward a number of arguments, the most prominent of which are irreducible complexity and specified complexity, in support of the existence of a designer. The scientific community rejects the extension of science to include supernatural explanations in favor of continued acceptance of methodological naturalism, and has rejected both irreducible complexity and specified complexity for a wide range of conceptual and factual flaws.
Intelligent design was developed by a group of American creationists who revised their argument in the creation–evolution controversy to circumvent court rulings such as the United States Supreme Court Edwards v. Aguillard ruling, which barred the teaching of "Creation Science" in public schools as breaching the separation of church and state. The first significant published use of intelligent design was in Of Pandas and People, a 1989 textbook intended for high-school biology classes. From the mid-1990s, intelligent design proponents were supported by the Discovery Institute, which, together with its Center for Science and Culture, planned and funded the "intelligent design movement". They advocated inclusion of intelligent design in public school curricula, leading to the 2005 Kitzmiller v. Dover Area School District trial, where U.S. District Judge John E. Jones III ruled that intelligent design is not science, that it "cannot uncouple itself from its creationist, and thus religious, antecedents", and that the school district's promotion of it therefore violated the Establishment Clause of the First Amendment to the U.S. Constitution.