Bakhtin: "The Renaissance attitude toward laughter can be roughly and preliminarily characterized thus: laughter has a deep philosophical meaning; it is one of the most essential forms of truth about the world as a whole, about history, about the human being; it [...] sees the world differently, but no less (and perhaps more) essentially than does seriousness [...] Certain utterly essential aspects of the world are accessible only to laughter."
from Rabelais and His World, I believe