I recently came to know of an anecdote about Niels Bohr that the philosopher Slavoj Zizek claims to have read in a biography of Bohr. He doesn't specify the author or the biography.
The anecdote goes as follows: Bohr used to keep a horseshoe on the door of his house. In European (and Indian) superstitions, the horseshoe is believed to be an object that guards the house against the evil spirits. A friend, upon seeing the horseshoe on the door of Bohr's house, asked Bohr as to whether he subscribed to the relevant superstitions. Bohr replied that he didn't believe in them but he was told that the horseshoe works whether or not one believes in their power.
I tried to find an authentic historical account of the story but I could only find sparsely sourced articles which only claimed the story to be an anecdote. Is there an authentic historical account of the story being either true or false? Thanks!