A drunk is refused a drink

A drunk is refused a drink in a bar, so he undertakes to prove to the barman that he is sober. He gestures toward a cat near the doorway and says, “You see that cat coming in the door? It has two eyes. If I were drunk, I’d see four!” The bartender looks, then pauses a moment. Finally he responds, “You’re drunker than I thought!”, taking the rest of the alcohol away, “That cat isn’t coming in, it’s going out!”