Patents can stifle, as well as protect, stifle innovation
"The absence of patent protection would make it difficult if not impossible for many inventors to profit from their ingenuity. But when a second inventor vastly improves on an original idea, as Curtiss did, isn’t he equally entitled to reap the rewards of his own ingenuity? Even apart from questions of fairness, society benefits from both the original invention and its subsequent improvement. Both types of progress deserve legal protection."