Is God an Accident?
Hume thinks that we have a natural, but non-rational, tendency to see complexity as a product of intelligent design. Linked is an interesting article from The Atlantic Monthly that talks about the possible cognitive basis for this belief.
Stewart Guthrie, an anthropologist at Fordham University, was the first modern scholar to notice the importance of this tendency as an explanation for religious thought. In his book Faces in the Clouds, Guthrie presents anecdotes and experiments showing that people attribute human characteristics to a striking range of real-world entities, including bicycles, bottles, clouds, fire, leaves, rain, volcanoes, and wind. We are hypersensitive to signs of agency—so much so that we see intention where only artifice or accident exists. As Guthrie puts it, the clothes have no emperor.