Diachronic Natural Law

This chapter advances the theory of diachronic natural law, arguing that natural law evolves over time in response to human social practices and changing conceptions of human nature. Contrary to John Finnis’s view of natural law as timeless and immutable, Jonathan Crowe contends that Aquinas’s Treatise on Law supports a more dynamic and flexible interpretation. Through a detailed reading of Aquinas’s fourfold division of law—eternal, natural, human and divine—Crowe shows that all but eternal law are temporally situated and subject to change. The chapter highlights how Aquinas acknowledges shifts in natural law through the adaptation of secondary precepts, the role of custom, and the progressive revelation of divine law. Human law supplements natural law by specifying its indeterminate elements, often shaped by evolving customs and practices. Crowe concludes that natural law is historically contingent, reflecting both the limitations and the growth of human reason and society over time.