The theory of intelligent design holds that certain features of the universe and living things are best explained by an intelligent cause, and are not the result of an undirected, chance-based process such as Darwinian evolution.
Intelligent design begins with observations about the types of information produced by intelligent agents. Even the atheist zoologist Richard Dawkins says that intuitively, "[b]iology is the study of complicated things that give the appearance of having been designed for a purpose." Darwinists believe natural selection did the "designing" but intelligent design theorist Stephen C. Meyer notes, "in all cases where we know the causal origin of 'high information content,' experience has shown that intelligent design played a causal role."
Intelligent design implies that life is here as a result of the purposeful action of an intelligent designer, standing in contrast to Darwinian evolution, which postulates that life exists due to the chance, purposeless, blind forces of nature.
Intelligent Design through the Scientific Method:
The ways that intelligent agents act can be observed in the natural world and described. When intelligent agents act, it is observed that they produce high levels of "complex-specified information" (CSI). CSI is basically a scenario which is unlikely to happen (making it complex), and conforms to a pattern (making it specified). Language and machines are good examples of things with much CSI. From our understanding of the world, high levels of CSI are always the product of intelligent design.
If an object in the natural world was designed, then we should be able to examine that object and find the same high levels of CSI in the natural world as we find in human-designed objects.
We can examine biological structures to test if high CSI exists. When we look at natural objects in biology, we find many machine-like structures which are specified, because they have a particular arrangement of parts which is necessary for them to function, and complex because they have an unlikely arrangement of many interacting parts. These biological machines are "irreducibly complex," for any change in the nature or arrangement of these parts would destroy their function. Irreducibly complex structures cannot be built up through an alternative theory, such as Darwinian evolution, because Darwinian evolution requires that a biological structure be functional along every small-step of its evolution. "Reverse engineering" of these structures shows that they cease to function if changed even slightly.
Because they exhibit high levels of CSI, a quality known to be produced only by intelligent design, and because there is no other known mechanism to explain the origin of these "irreducibly complex" biological structures, we conclude that they were intelligently designed.
Intelligent Design as a Theory of Information:
Putting Intelligent Design to the Test: