A kid walked up with a leather basketball that he had found in the gym. "I’ve asked everyone if this is theirs," 
he said, "and no one claims it. There’s no name on it. Can I keep it?" It was the first sign of dishonesty I’d ever noticed in this young man, so I was surprised. "No," I said, "of course not." He begged for a while, as kids sometimes do. Finally, I asked, "Why would you even think about keeping it?"
He considered his answer carefully, probably because he knew what he was asking was wrong. "Well," he said, "I think I can keep it because we don’t know whose it is."
"That is true," I said, "we don’t know whose it is. But, we do know whose it isn’t."
And really, isn’t it all as simple as that?
