Patent law’s broad exclusionary rule is one of its defining features. It is unique within intellectual property as it prohibits acts of independent creation. Even if a second inventor had no connection or aid from an initial inventor, patent law allows the first inventor to stop the second. Even though a number of pressing problems can be traced to this rule, it remains untouchable; it is thought to be essential for incentivizing invention. But is it really our only choice? And why is it so different from our otherwise widespread reliance on free entry and competition in markets? The current rule and its anti-competitive stance are defended as being economically necessary as well as being administratively manageable. This article questions ...