An Intentional Tort Theory of Patents

This Article challenges the dogma of U.S. patent law that direct infringement is a strict liability tort. Impermissibly practicing a patented invention does create liability even if the infringer did not intend to infringe or know about the patent. The consensus is that this is a form of strict liability. The flaw in the consensus is that it proves too little, for the same is true of intentional torts: intent to commit the tort is unnecessary, and ignorance of the legal right is no excuse. What is relevant is intent to perform the action that the law deems tortious. So for the tort of patent infringement, the question is whether liability should require that the infringer intended to perform the actions that constitute infringement. The patent statute and the few cases that have broached the question suggest the answer is yes — tortious intent should be necessary. However, patent law currently takes no position on tortious intent. The strict liability view is merely a default. This Article fills that gap by applying ordinary tort principles to patent infringement. The proposed framework offers a powerful policy lever for important issues implicating the notice function of patents, including divided infringement, claim construction, and inherency. This framework also mitigates the effects of patent assertion on risk allocation in the patent system by differentiating among makers, sellers, and users of patented innovation — a distinction that is economically important but has no principled basis in patent doctrine