Two theoretical physicists are lost at the top of a mountain. Theoretical physicist No 1 pulls out a map and peruses it for a while. Then he turns to theoretical physicist No 2 and says: "Hey, I've figured it out. I know where we are."
"Where are we then?"
"Do you see that mountain over there?"
"Yes."
"Well… THAT'S where we are."
I heard this joke at a physics conference in Les Arcs (I was at the top of a mountain skiing at the time, so it was quite apt). It was explained to me that it was first told by a Nobel prize-winning experimental physicist by way of indicating how out-of-touch with the real world theoretical physicists can sometimes be.
Jeff Forshaw, professor of physics and astronomy, University of Manchester