The Origins of the Concept of Natural Law in Ancient Greece

This chapter explores the origins of natural law theory, challenging the view that it began with the Stoics. It argues instead that its roots lie with the Sophists of fifth-century bce Athens. The chapter examines Stoic natural law as articulated by Cicero, emphasising its rational, universal and immutable character. It then analyses Plato and Aristotle, noting their partial endorsements of natural law principles, such as justice rooted in nature and cosmic order. However, it shows that both were critical of the egalitarian implications of natural law as expressed by some Sophists. The chapter identifies these earlier thinkers, particularly opponents of slavery like Alcidamas, Antiphon and Hippias, as the true originators of natural law. They argued from human equality and natural justice against social hierarchies like slavery. The chapter concludes that the earliest natural law theorists were radical and egalitarian, whose ideas were marginalized by later thinkers but remain foundational to the tradition.