Natural law

Natural law (Latin: ius naturale, lex naturalis) is a philosophical and legal theory that posits the existence of a set of inherent laws derived from nature and universal moral principles, which are discoverable through reason. In ethics, natural law theory asserts that certain rights and moral values are inherent in human nature and can be understood universally, independent of enacted laws or societal norms. In jurisprudence, natural law—sometimes referred to as iusnaturalism or jusnaturalism—holds that there are objective legal standards based on morality that underlie and inform 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 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 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'). Aquinas argues that because human beings have reason, and because reason is a spark of the divine, all human lives are sacred and of infinite value compared to any other created object, meaning everyone is fundamentally equal and bestowed with an intrinsic basic set of rights that no one can remove.

Modern natural law theory took shape in the Age of Enlightenment, combining inspiration from Roman law, Christian scholastic philosophy, and contemporary concepts such as social contract theory. It was used in challenging the theory of the divine right of kings, and became an alternative justification for the establishment of a social contract, positive law, and government—and thus legal rights—in the form of classical republicanism. John Locke was a key Enlightenment-era proponent of natural law, stressing its role in the justification of property rights and the right to revolution. In the early decades of the 21st century, the concept of natural law is closely related to the concept of natural rights and has libertarian and conservative proponents. Indeed, many philosophers, jurists and scholars use natural law synonymously with natural rights (Latin: ius naturale) or natural justice; others distinguish between natural law and natural right.

Plato did not have an explicit theory of natural law, but his concept of nature, according to John Wild, contains some of the elements of many natural law theories. According to Plato, we live in an orderly universe. The basis of this orderly universe or nature are the forms, most fundamentally the Form of the Good, which Plato calls "the brightest region of Being". The Form of the Good is the cause of all things, and a person who sees it is led to act wisely. In the Symposium, the Good is closely identified with the Beautiful, and Plato describes how Socrates's experience of the Beautiful enabled him to resist the temptations of wealth and sex. In the Republic, the ideal community is "a city which would be established in accordance with nature".

Greek philosophy emphasized the distinction between "nature" and "law", "custom", or "convention".^{[citation needed]} What the law commanded is expected to vary from place to place, but what is "by nature" should be the same everywhere. A "law of nature" therefore has the flavor more of a paradox than something that obviously existed. Against the conventionalism that the distinction between nature and custom could engender, Socrates and his philosophic heirs, Plato and Aristotle, posited the existence of natural justice or natural right. Aristotle is often said to be the father of natural law.

Aristotle's association with natural law may be due to Thomas Aquinas's interpretation of his work. But whether Aquinas correctly read Aristotle is in dispute.^{[citation needed]} According to some, Aquinas conflates natural law and natural right, the latter of which Aristotle posits in Book V of the Nicomachean Ethics (Book IV of the Eudemian Ethics). According to this interpretation, Aquinas's influence was such as to affect a number of early translations of these passages in an unfortunate manner, though more recent translations render them more literally. Aristotle notes that natural justice is a species of political justice, specifically the scheme of distributive and corrective justice that would be established under the best political community; if this took the form of law, it could be called a natural law, though Aristotle does not discuss this and suggests in the Politics that the best regime may not rule by law at all.

The best evidence of Aristotle's having thought there is a natural law is in the Rhetoric, where Aristotle notes that, aside from the "particular" laws that each people has set up for itself, there is a "common" law that is according to nature.^{[edition needed]} Specifically, he quotes Sophocles and Empedocles: