Recently, at a party in New York, I mentioned that I had been talking to various groups in the United States and Europe about investment opportunities in the commodities market. Before I could get out one more word, a woman interrupted me. “Commodities!” she exclaimed, with the kind of incredulity in her voice that Manhattanites reserve for people moving to Los Angeles. “But my brother invested in pork bellies and lost his shirt. And he’s an economist!”