Sean B. Carroll writes about science deniers in "The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution"

Now, nearly 150 years later, we can see. We no longer look at Nature's diversity "as a savage looks at a ship." From the new DNA record, the evidence of the workings of the evolutionary process abounds. But many people--a great many--either do not see what scientists see, or do not believe what scientists have concluded.

I have borrowed the title of this chapter from the wonderful book Seeing and Believing by Richard Panek, about the invention of the telescope and how it changed our perception of the sky and our place in the universe. Like Darwin, Galileo's observations and ideas were rejected by authorities who had no use for new evidence or ideas. But, eventually, the observable evidence overwhelmed ideological resistance. For all of those who do see the overwhelming evidence of natural selection and life's descent from ancestors, and the immense span of time over which the story of life unfolded, it is, to put it mildly, baffling how so many still do not. It is absolutely astonishing and often infuriating that some take it so far as to deny the immense foundation of evidence and to slander all the human achievement that foundation represents.

With the facts on evolution's side, how can this doubt and denial persist, or even be growing, here at the outset of the twenty-first century?