Irreducible complexity (IC) is the argument that certain biological systems with multiple interacting parts would not function if one of the parts were removed, so supposedly could not have evolved by successive small modifications from earlier less complex systems through natural selection, which would need all intermediate precursor systems to have been fully functional. This negative argument is then complemented by the claim that the only alternative explanation is a "purposeful arrangement of parts" inferring design by an intelligent agent. Irreducible complexity has become central to the creationist concept of intelligent design (ID), but the concept of irreducible complexity has been rejected by the scientific community, which regards intelligent design as pseudoscience. Irreducible complexity and specified complexity, are the two main arguments used by intelligent-design proponents to support their version of the theological argument from design.
Michael Behe believes that many aspects of life show evidence of design, using the mousetrap in an analogy disputed by others.
Intelligent design (ID) is a pseudoscientific argument for the existence of God, presented by its proponents as "an evidence-based scientific theory about life's origins". Proponents claim 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." ID is a form of creationism that lacks empirical support and offers no testable or tenable hypotheses, and is therefore not science. The leading proponents of ID are associated with the Discovery Institute, a Christian, politically conservative think tank based in the United States.
William A. Dembski proposed the concept of specified complexity.
The Discovery Institute's Center for the Renewal of Science and Culture used banners based on The Creation of Adam from the Sistine Chapel. Later it used a less religious image, then was renamed the Center for Science and Culture.
