Is Intelligent Design Viable?

Update from Brian: For those interested in the audio, it can be found here.

On Nov. 5, Campus Crusade Sponsored a debate entitled "Intelligent Design: Is it Viable?" between philosopher William Lane Craig and biologist Francisco J. Ayala at the Indiana University Auditorium. While I cannot recap the entire debate here, I would like to state a few important points.

Dr. Craig gave the best spoken presentation of Intelligent Design (ID) that I have ever seen. He kept the debate at a very respectable and dignified level. His points and questions made me think more about this issue than I have in some time. He argued simply that ID is viable, not necessarily true. His definition and presentation of ID were also surprisingly narrow and modest for three reasons.

First, he accepted some level of common ancestry for diverse organisms. While he did not accept that all organisms were descended from a common ancestor, he easily accepted that all organisms in a given order or family could share common ancestry. I found this surprising because he made no attempt to challenge the descent of humans from earlier ape-like ancestors.

Second, many alleged flaws and cruelties in nature were cited as arguments against design, such as parasites, male baboons killing the babies of a rival, or the high spontaneous abortion (miscarriage) rate (at least 15%) in humans. Dr. Craig responded that a designer can still be inferred from very sub-optimal designs, such as the East German Trabant, a notoriously low-quality car. Even devices that are cruel and immoral can still be the obvious products of design; he used the example of a medieval torture rack. Overall, he argued that ID makes no claim that the designer is all-good or all-powerful. He quoted another ID advocate who said, "Zeus will do!"

Third, Dr. Craig conceded that ID might not be science; he argued that this was not relevant because an idea need not be scientific to be true. I think the question is more relevant than Dr. Craig does for practical reasons. For instance, if ID is not science, advocates should not sue school districts for not including it in science classes.

In defining ID theory, Dr. Craig used two criteria that William Dembski has posited to justify an inference of design. First, the event or object in question must be wildly improbable. Second, it must conform to a pre-specified pattern. Dr. Craig claimed that these criteria are used to detect design in fields like cryptography, forensic science, arson investigations, and the Search for Extra-Terrestrial Intelligence (SETI). He claimed that to declare ID non-viable, one must either attack the criteria or show that biological systems do not satisfy them.

I take issue with the second criterion. Police can use it to determine if arson caused a fire because they know how humans start fires. SETI implicitly assumes that the aliens will be enough like us (or want enough to be found by us) that we will be able to differentiate their signals from natural sources. This is a limitation of SETI that I had not recognized before this debate.

In Dr. Craig's formulation of ID, the designer can be anything from Jesus to Zeus to the designer of torture devices. With such a vague definition of a designer, I do not understand how one could pre-specify any pattern with enough precision to ever use Dembski's second criterion. When confronted with a seeming violation of the second criterion, even a determined ID advocate who specifies the Christian God could simply refer to our limited knowledge of God's intentions, reasons, and motivations (e.g. Isaiah 55:8) to avoid the criterion and thus render it useless.

While I was impressed by Dr. Ayala's overall performance, he did leave one important question, which Dr. Craig asked multiple times, unanswered. What is the evidence that natural selection, which works on small scales, is powerful enough to explain all of life? He cited the specific example of a whale and a bacterium being descended from the same ancestor. I would appreciate if any of the readers of this post could point me to such evidence.