It is common among historians of the Western intellectual tradition to note that the origins of that tradition reside in the ancient Hellenistic world. The ancient thinkers tended to develop whole systems that united explanations for their observations of physical phenomena with explanations of what could not be directly observed – that is, metaphysics. This chapter shows the relevance of Hellenistic ethical thought for what we might call the Western tradition. It provides a background to the more focused discussion on important issues of method in economics. Historians of religion have noted that Christianity had its start as a relatively minor sect of Judaism. Epicureanism received a similarly mixed reception by the Renaissance thinkers. The chapter also draws attention to the impact of ancient philosophy upon the theories of three classical economists who are often also considered to have made important contributions to moral philosophy. These are Adam Smith, John Stuart Mill, and Karl Marx.