The premise that innovation prospers when ideas can serendipitously connect and recombine with other ideas may seem logical enough, but the strange fact is that a great deal of the past two centuries of legal and folk wisdom about innovation has pursued the exact opposite argument, building walls between ideas. Ironically, those walls have been erected with the explicit aim of encouraging innovation. They go by many names: intellectual property, trade secrets, proprietary technology, top-secret R&D labs. But they share a founding assumption: that in the long run, innovation will increase if you put restrictions on the spread of new ideas, because those restrictions will allow the creators to collect large financial rewards from their inventions. And those rewards will then attract other innovators to follow in their path.