An American scientist once visited the offices of the great Nobel prize
winning physicist, Niels Bohr, in Copenhagen. He was amazed to find that
over Bohr's desk was a horseshoe, securely nailed to the wall.
The American said with a nervous laugh, "Surely you don't believe the horseshoe will bring you good luck,
do you, Professor Bohr? After all, as a scientist --"
Bohr chuckled. "I believe no such thing, my good friend. Not at all. I am
scarcely likely to believe in such foolish nonsense. However, I am told
that a horseshoe will bring you good luck whether you believe in it or not."