Natural law is a philosophical and legal doctrine that postulates that certain rights or values are inherent by virtue of human nature and universally cognizable through human reason. Historically, natural law refers to the use of reason to analyze both social and personal human nature to deduce binding rules of moral behavior. The concept of natural law originated in ancient Greek philosophy, particularly with Aristotle, and was further developed in the Roman era by thinkers such as Cicero. The crux of Aristotle's concept was the discernment of natural justice—an order inherent in the natural world that human reasoning could grasp.
In the Middle Ages, the theory of natural law blossomed afresh within the framework of Christian theology. St. Thomas Aquinas, in his seminal work "Summa Theologica," argued that natural law is part of the divine law, given to mankind by God but discernible independently of divine revelation through human reason. Aquinas posited that the natural law is immutable and eternal, and serves as a moral foundation for human-made laws. He categorized this under the broader scholastic axiom that "grace does not destroy nature, but perfects it," implying that divine laws elevate rather than negate the rational and natural order.
During the Enlightenment, the concept of natural law evolved to become closely associated with the development of modern human rights theory. Enlightenment thinkers such as John Locke believed that natural law rights include life, liberty, and property, which governments must protect to ensure social stability. Locke’s formulations were pivotal in influencing the liberal philosophies of the modern Western world, particularly visible in the political structures of democracies. His ideas were foundational to the American Declaration of Independence in 1776, which famously asserts that it is "self-evident" that all men are endowed with certain inalienable rights, and that to secure these rights, governments are instituted.
In contemporary discourse, natural law theory continues to influence legal debates and philosophical discussions around ethics, human rights, and the nature of law itself. It provides a vital counterpoint to legal positivism, which holds that law is determined solely by statutes and societal norms rather than by inherent human rights or moral codes. Critics of natural law argue that its principles can be too vague and subjective, varying greatly between cultures and over time. Nevertheless, the enduring appeal of natural law lies in its advocacy for an objective moral truth grounded in universal human reason and experience. As societies continue to grapple with complex issues like bioethics, cyberjustice, and transhumanism, the principles of natural law offer a framework for asserting universal human dignity and justice.