A Russian astronaut and a Russian brain surgeon were once discussing religion. The brain surgeon was a Christian but the astronaut was not. The astronaut said, "I've been out in space many times but I've never seen God or angels." And the brain surgeon said, "And I've operated on many clever brains but I've never seen a single thought."

source: Jostein Gaardner, Sophie's World 230 tags: Apologetics, Atheism, Universe