A Baffling Discovery

Performer places five cards in a row on the table, turns his back and asks a spectator to look at one of the cards, remember it, and replace it in its original position. Magician then gathers up the five cards, and showing his trousers' pocket to be empty, places the cards in it. He states that he will remove all the cards but the selected one from his pocket. He does so, and finally removes the fifth card and shows it to be the selected one.