The monk was silent for a moment. "It’s not easy to explain," he said at last. "Actually, in the writings that survive, there’s no direct information about the construction of a dynamo. Rather, you might say that the information is implicit in a whole collection of fragmentary writings. Partially implicit. And it has to be got out by deduction. But to get it, you also need some theories to work from-theoretical information our predecessors didn’t have."