Mullah Nasruddin and Rabbi Moishe were traveling through the desert. It was so hot that the air was shimmering. In the distance they saw something black on the ground. Rabbi Moishe said, "It's a vulture." Mullah Nasruddin said, "No, it's a goat." They drew closer, still arguing over what it was. Rabbi Moishe threw a rock at it. It flapped its wings and lifted into the air. "See!" said Rabbi Moishe. "I told you it was a vulture."

"That doesn't prove anything," Mullah Nasruddin. "It could be a goat with wings."