According to several sources, Daniel Boorstin, the late historian and former Librarian of Congress, wrote:
I have observed that the world has suffered far less from ignorance than from pretensions to knowledge. It is not skeptics or explorers but fanatics and ideologues who menace decency and progress. No agnostic ever burned anyone at the stake or tortured a pagan, a heretic, or an unbeliever.
Does anyone know in what book or essay, or speech, he wrote or said that, and when?