II.

Classical Theories

The ancient Greek philosophers were the first to elaborate a doctrine of natural law. In the 6th century bc, Heraclitus spoke of a common wisdom that pervades the whole universe, “for all human laws are nourished by one, the divine”. Aristotle distinguished between two kinds of justice: “A rule of justice is natural that has the same validity everywhere, and does not depend on our accepting it or not; a rule is legal [conventional] that in the first instance may be settled in one way or the other indifferently.” The Stoics, especially the philosopher Chrysippus of Soli, constructed a systematic natural law theory. According to Stoicism, the whole cosmos is rationally ordered by an active principle, the logos, variously named God, mind, or fate. Every individual nature is part of the cosmos. To live virtuously means to live in accord with one's nature, to live according to reason. Because passion and emotion are considered irrational movements of the soul, the wise individual seeks to eradicate the passions and consciously embrace the rational life. This doctrine was popularized among the Romans by the 1st-century bc orator Cicero, who gave a famous definition of natural law in his De Republica: “True law is right reason in agreement with Nature; it is of universal application, unchanging and everlasting; it summons to duty by its commands, and averts from wrongdoing by its prohibitions ... There will not be different laws at Rome and at Athens, or different laws now and in the future, but one eternal and unchangeable law will be valid for all nations and for all times.” In the Corpus Juris Civilis a compilation and codification of Roman legal material prepared in 534 under Emperor Justinian I, a jus naturale is acknowledged, but there is no assertion that natural law is superior to positive law and no vindication of human rights (slavery, for example, was legal).