According to Osho, 'knowledgeable' people—stuffed with second-hand facts and conclusions—are the most ridiculous, because their borrowed certainties replace living intelligence. Laughter explodes this pretension. He laughs to expose the stupidity of head-heavy knowing without awareness, to free us from reverence for dead knowledge, and to invite a return to innocence, direct seeing, and playful, present-moment wisdom.
He laughs because just having lots of facts without real understanding is silly, and laughing helps us drop pretend knowing and see with our own eyes.