Natural law

Natural law (Latin: ius naturale, lex naturalis) is a philosophical and legal theory that posits the existence of inherent laws derived from nature and universal moral principles that are discoverable through reason. In ethics, natural law theory asserts that certain rights and moral values are inherent in human nature and can be universally understood, independent of enacted laws or social norms. In jurisprudence, natural law—sometimes referred to as iusnaturalism or jusnaturalism—holds that there are objective legal standards based on morality that underlie the creation, interpretation, and application of human-made laws. This contrasts with positive law (as in legal positivism), which emphasizes that laws are rules created by human authorities and are not necessarily connected to moral principles. Natural law can refer to "theories of ethics, theories of politics, theories of civil law, and theories of religious morality", depending on the context in which naturally-grounded practical principles are claimed to exist.

In the Western tradition, natural law was anticipated by the pre-Socratics, for example, in their search for principles that governed the cosmos and human beings. The concept of natural law was documented in ancient Greek philosophy, including Aristotle, and was mentioned in ancient Roman philosophy by Cicero. References to it are also found in the Old and New Testaments of the Bible, and were later expounded upon in the Middle Ages by Christian philosophers such as Albert the Great and Thomas Aquinas. The School of Salamanca made notable contributions to natural law theory during the Renaissance.

Although the central ideas of natural law had been part of Christian thought since the Roman Empire, its foundation as a consistent system was laid by Aquinas, who synthesized and condensed his predecessors' ideas into his Lex Naturalis (lit. 'natural law').