Problems And Mysteries

Our ignorance can be divided into problems and mysteries.  When we face a problem, we may not know its solution, but we have insight, increasing knowledge, and an inkling of what we are looking for.  When we face a mystery, however, we can only stare in wonder and bewilderment, not knowing what an explanation would even look like. 

-- Steven Pinker (1954 -), Canadian-born American experimental psychologist, cognitive scientist, and popular science writer, How the Mind Works, explaining Noam Chomsky's position