An MIT professor gives a student $5 and says: send any amount to a stranger in this room. Whatever you send triples. The stranger decides how much comes back. Rational answer: send nothing. You lose every dollar you trust. Most students send almost everything. Most strangers return more than half. The math says keep it. The room says otherwise. Then the professor runs a different game. Same cash. Same room. One student splits. The other can only accept. No rejection. No consequences. The offers collapse. Not to zero. But enough to see the line between generosity and strategy. One year a student got Swiss chocolate instead of cash. She was lactose intolerant. Gave away 100%. The professor noted it. The class laughed. Nobody noticed the point. She had zero cost of generosity. The moment giving costs nothing, everyone is generous. The moment real money hits the table, the room divides into the same two groups every semester. People who send first. People who wait. Labor, capital, arbitrage, insurance. Four ways to make money. All four require the same opening move. You send value before you see a return. A paycheck after the work. A deposit before the interest. A bet before the edge. A premium before the claim. The lecture is free. MIT filmed it years ago. The game runs every semester. The split barely changes. Sending first is free. Knowing if it comes back is the part that costs something.