From an interview with philosopher Stephen Law in New Scientist on his new book, Believing Bullshit:
Some things may be beyond our understanding, and sometimes it’s reasonable to appeal to mystery. If you have excellent evidence that water boils at 100°C, but on one occasion it appeared it didn’t, it’s reasonable to attribute that to some mysterious, unknown factor. It’s also reasonable, when we have a theory that works but we don’t know how it works, to say that this is currently a mystery. But the more we rely on mystery to get us out of intellectual trouble, or the more we use it as a carpet under which to sweep inconvenient facts, the more vulnerable we are to deceit, by others and by ourselves.