The Numerus Clausus Principle, Property Customs, and the Emergence of New Property Forms

The numerus clausus debate has focused on the principle's explanatory power in the American common law, but the available theory is not as readily applicable to the civil law context. The numerus clausus principle present in the civil codes is often stricter than it is in practice courts in several jurisdictions have allowed property customs to create new property forms. In this Essay, we advance a more general theory of optimal standardization to explain this principle in both the common law and the civil law. We also point out that the numerus clausus principle and property customs (whether they create new property forms or not) both involve an "informational trade-or between extensiveness of the audience and intensiveness of the conveyed message. We propose four propositions regarding whether customs would become de jure. Our study on the dynamics between the numerus clausus principle and property customs in East Asia in general, and the case study on the "small property rights" in Taiwan in particular, provide real-world evidence for these propositions.