It's a simple idea we learn from our early childhood: We laugh when we're happy and cry when we're sad.
But sometimes it's not that simple. What happens when you laugh at a video of someone falling off a ladder, or find yourself straining to avoid hysterics when a home video shows a son hitting a line drive into his father's groin?
All of this points to a simple conclusion: Pain makes us laugh.
The ancient Greeks knew it, 17th century philosopher Thomas Hobbes knew it when he wrote...Full Story