Why did anyone ever believe Darwinism?

While we're here, Phillip Johnson, the California law prof who put intelligent design on the intellectual map, asks in Think, the Royal Institute of Philosophy's publication, why did anyone ever believe in mud to mind, molecules to man, and other theories of unintelligent design:

Nowadays I rarely see any attempt to prove that the Darwinian mechanism actually has the power to create major new biological innovations. Instead, the museums and magazines prefer just to tell the story of common descent, assuming that random variation with natural selection (differential reproduction) must have been adequate to perform whatever designing had to be done. At the same time, mainstream science, although guided by Darwinian assumptions, keeps providing more and more evidence of the enormous information content of living structures. Even the core assumption that genetic similarities are necessarily inherited from common ancestors is contradicted almost daily by invocations of something called “lateral gene transfer” to explain genetic similarities between organisms which are not believed to share a recent common ancestor. Today authoritarian rules ban the hypothesis of intelligent design from scientific discussion and fiercely suppress it by lawsuits. A genuinely confident scientific culture that was making continual progress in confirming its theories and solving problems would not need or want to rely on intimidation to silence dissent. It may require many long years of struggle before the hypothesis of real design in biology will be able to receive a fair hearing, but the day of that fair hearing will arrive, and eventually people may wonder how a materialist theory as shaky as Darwinism was able to captivate so many minds for so long.

Well, one may as well ask, why did Freudianism capture the public for so long? One reason is that when third-raters proffer unfalsifiable explanations - without themselves having the least sense that they might not be proferring wisdom - they can sound very, very convincing. They act as thought they have discovered the source of truth, and the unwary believe them.

The Freudian honestly believed that your behaviour as a mid-life adult can be entirely traced to early childhood traumas, and challenged you to prove otherwise. In the same way, the Darwinist honestly believes that creativity can be had for free without intelligence, and can't imagine otherwise, despite the evidence. Not only that but - zealous as he is for the cause - he knows it is his duty to persecute any who doubt.

Johnson's comments on the hype surrounding the Galapagos finches are interesting in this context.