Although markets are based on legal foundations and judiciary problems often concern economic issues, the twentieth century saw a progressive methodological divide between legal and economic studies. In particular, economic theory stands on quite simplistic legal concepts that contribute to hide some important issues at stake. This divide has not been reduced much by the development of the field of law and economics, which simply applies the economics method to legal issues. A necessarily more fruitful field of interaction between these perspectives is promised by social economics, which, since its beginning, has adopted a more integrated and interdisciplinary approach, including the study of property rights and institutions. In particular, among the many issues debated in social economics, the theme of justice in economic exchanges over the course of history has stimulated much fruitful research that still deserves to be further developed. In this field of research, the study of the legal variables comes into direct interaction with economic reasoning. Consequently, categories used in the economic analysis should be harmonized with the legal framework. On the other hand, the choice of the legal theory on which we develop social economy studies is crucial in determining what can and what cannot be seen in terms of pathologies in human interaction. Modernity brought the idea of individual property rights as a complex phenomenon. However, economics adopted a simplistic view of property as a fundamental institution, understating the complex interaction of different rights and obligations that frame the legal environment of economic processes with an insufficiently elaborated tool. Here, a more elaborate view of legal elements will be proposed