Ownership has long been a basic principle of western society. Yet during the last century, property rights have been increasingly curbed by courts and legislatures, as they grapple with collective vs. individual control of physical and human assets. Property ultimately involves personal control and security, as often opposed to other individual interests or the overall interest or advantage of society. How are possessions legitimately acquired, used, and sold? Are property rights based on human agreement, on the "natural order" of things, or on a divine law?