ABSTRACT
"Natural law" is an expression with several meanings in several areas of normative inquiry. This chapter uses the phrase to refer to the tradition of moral, political and legal thinking which has developed, particularly within Catholicism, since the time of Thomas Aquinas and which regards his ethical and political writings as the classical source. It states the natural law conception of ownership, and indicates the normative foundation of its key claims and some areas where clarification is needed. The chapter sketches several implications of the conception for thinking about ownership of the world's natural resources. Natural law discussions of property since Aquinas have sought to elaborate a set of moral standards by which decisions of owners and established ownership arrangements could be morally evaluated and the development of better arrangements rationally guided. The natural law conception of ownership is complex. It is a function of the combination of several more primitive normative considerations.
