Keystone/Getty Images The late economist Arthur Lewis had a reputation as a very kind, principled, quiet and contemplative thinker. And in August of 1952, he was strolling down a road in Bangkok, Thailand — when suddenly he had a flash of insight about a problem that had been baffling him. Lewis observed that when the economy of a poor country starts growing faster, the new businesses in that country make a lot of money, and they do hire a lot of workers, but it takes a long time before the wages that those businesses pay to workers also start going up. That was the puzzle that Arthur Lewis solved.