A world-famous tightrope walker strung a wire across Niagara Falls and invited the public to come and see him walk across. On the day he was to do it, thousands of people showed up to watch. As he walked to the wire they cheered loudly. He stopped and asked them, “Do you believe I can do it?” They cheered, “Yes”. Then he walked across. He then asked them, “Do you believe I can do it again with a 100 lb. bag on my shoulders?” Again, they cheered and he walked across once more. A third time he asked the crowd, “Do you believe I can do it again carrying a man on my shoulders?” A loud roar went up. “Yes”, they shouted. "All right then, who will volunteer to be that man?" Not a sound could be heard.