Yesterday's post addressed the topic of what kind of theory intelligent design is and whether it's guilty of the "god of the gaps" fallacy. Those who don't closely follow the problem of the origin of life and related matters are often confused by the welter of conflicting views on the subject so I thought it might be helpful to offer thumbnail sketches of the major options in this very perplexing and very important debate.
Darwinian Evolution (DE): The Darwinian version of evolution is based upon a naturalistic worldview. It holds that all of life arose through natural processes like natural selection, genetic mutation, and genetic drift acting in accord with the laws of nature and that there was no non-natural intervention or activity of any kind involved. This view doesn't necessarily rule out God's existence but it does leave Him with very little to do and thus quite irrelevant.
Special Creation (SC): The view that God created the major taxa (classes and/or phyla) of living things de novo. On young earth special creation God accomplished this in six days approximately ten thousand years ago. On the old earth creationist view His creative activity was spread out over billions of years. SC is ultimately an attempt to reconcile the physical evidence of life with the Genesis account of the Bible.
Theistic Evolution (TE): This is similar to Darwinian evolution except that on TE God initially created the laws of nature (and perhaps initiated the Big Bang) that led to the development of living things. Some versions of TE hold that God guided the evolutionary process while others hold that once God created the world He left the evolutionary process to unfold on its own. Both versions agree that belief in God's existence and creative activity is a matter of faith, that there's no evidence of God to be found in the natural world and that all apparent design can be explained in terms of the action of natural forces and processes.
Intelligent Design (ID): This view maintains, contrary to both DE and TE, that both living things and the finely-tuned physical world display the signs of having been engineered by an intelligent agent. Unlike SC, ID takes no official stance on how long ago this happened, or how it was done, or even who the intelligent agent was. It does not attempt to reconcile the empirical evidence with Genesis but rather to follow the evidence wherever it leads. Nor, as was argued in yesterday's post, does ID commit the "god of the gaps" fallacy but is instead an example of a common form of scientific reasoning called inference to the best explanation. Some ID theorists in their personal lives are special creationists, some are evolutionists (though not naturalistic evolutionists), and, surprisingly, there are even one or two who are atheists.
Although most proponents of ID are theists those who are atheists leave open the possibility that the intelligent agent who designed the universe and living things could be a denizen of some other world in the multiverse and not the God of traditional theism. The notion that our universe is a computer simulation designed by an intelligent being in some other universe is compatible with this view. Even so, in practice almost all atheists are Darwinian evolutionists and most theists fall somewhere among the other three options.
The debate is important because if it could be shown that Darwinian (or naturalistic) evolution is an unsatisfactory explanation of the appearance of information-rich biological systems or the fine-tuning of the cosmos it would seriously undermine naturalism and make it a much less tenable philosophical position, at least until some other naturalistic theory of origins could be found.