This lecture discusses the impact of the Sophists on public policy and private morality in 4th century B.C.E. Some see Sophistic analysis of conventional law based on premises about nature as a forerunner to political science. This lecture considers Sophist attitudes about power, morality, and religion, and concludes with a case study: the Melian dialogue, a famous passage from Thucydides, the Sophist-influenced 5th-century historian whose book on the Peloponnesian War is hailed as the first work of social science.