A Study in Skepticism
A student heard Rabbi Yochanan's sermon about the gates which G-d would install at the entrance to Jerusalem in the hereafter. A gateway of 10 by 20 cubits would be cut out of precious jewels measuring 30 by 30 cubits. The skeptical student mockingly remarked that if we are unable to locate jewels even the size of a small bird's egg how can we believe that such tremendous jewels will ever exist? On a subsequent sea journey this unbelieving student saw heavenly angels sawing away at jewels of 30 by 30 to make an opening of 10 by 20. When he asked them what this work was intended for, they replied that they were preparing the future gates of Jerusalem. Upon his return to Rabbi Yochanan this now believing student reported that he had actually seen what his master had described. Rabbi Yochanan's response was that if he believed what he had heard only because he saw it with his own eyes he was guilty of mocking the words of the Sages and the outraged Sage's disapproving gaze turned the skeptic into a pile of bones.
Tosefos in Masechta Chulin 57b raises the question as to why the severe judgment visited upon this skeptic did not apply to Rabbi Shimon ben Chalafta who conducted a scientific experiment to test King Solomon's description of the ants as having no ruler. His resolution is that while Rabbi Yochanan's student actually questioned the truth of his master's teaching there was no question in the mind of Rabbi Shimon ben Chalafta of the truth of King Solomon's words. He simply wanted to determine whether the wisest of men knew this as a result of his own scientific exploration or of divine revelation.