No Dream Without Inaccuracies

The Gemara learns from Rashi's comment on Yosef's dream that there is no dream without some meaningless parts. Yaakov asks, “Will I and your mother come to bow down to you?” although Rachel was already dead. At the age of five, Rav Meshulem Igra challenged this in his cheder. First he asked why a single false detail in Yosef's dream should teach that every dream contains something untrue, since that seems to generalize from a specific case to a universal rule. Then, after a few minutes, he asked why Yosef mentioned the moon at all, when it invited his father's anger and cast doubt on the dream, and he could simply have left it out. His own answer joined the two questions. Yosef knew that every dream contains some inaccuracy. Had he omitted the moon, his father and brothers would have searched for other false details, so he told the dream in full, leaving nothing out. And from the fact that Yosef insisted on mentioning the moon, the Sages learn that there is no dream without inaccuracies.