What Is Natural Law: Political Philosophy

Direct Answer

Natural law is a moral and political theory that holds that certain rights, duties, and ethical principles are inherent in human nature and can be discovered through the exercise of reason, independently of the laws enacted by political authorities. The central claim of natural law theory is that there is a standard of right and wrong that is not created by human beings but is discovered by them -- a standard that is grounded in the nature of reality or the nature of human beings.

The practical significance of natural law theory lies in its implications for political authority. If there is a higher law that transcends human legislation, then positive laws -- the laws enacted by governments -- are not the final standard of justice. A law that violates natural law is not truly a law at all; it is, as Augustine put it, "a corruption of law." This means that citizens have a moral obligation to obey just laws but may have a right -- even a duty -- to resist unjust laws that violate the natural law.

Natural law theory is distinct from legal positivism, which holds that law is simply the command of the sovereign and that there is no necessary connection between law and morality. Natural law theorists argue that the concept of law itself contains a moral element: an unjust law is not merely a bad law but is, in some sense, not a law at all.

Historical Context

The origins of natural law theory lie in ancient Greek and Roman philosophy. The Stoics, particularly Cicero, developed the idea of a universal law of nature that applies to all human beings everywhere. In De Re Publica (On the Commonwealth), Cicero wrote: "True law is right reason in agreement with nature; it is of universal application, unchanging and everlasting. It is a sin to try to alter this law, nor is it allowable to attempt to repeal any part of it."

Cicero's conception of natural law profoundly influenced Roman jurisprudence and, through it, the Western legal tradition. The Roman jurists recognized that there were principles of justice that were common to all peoples (ius gentium, the law of nations) and principles that were grounded in the nature of things (ius naturale, natural law).

The most systematic development of natural law theory was provided by Thomas Aquinas in the thirteenth century. In his Summa Theologica, Aquinas distinguished four kinds of law: eternal law (the divine reason that governs the universe), natural law (the participation of rational creatures in the eternal law), divine law (the law revealed in Scripture), and human law (the laws enacted by human authorities). Natural law, Aquinas argued, is the foundation of human law: human laws are just only insofar as they are derived from the natural law.

Aquinas argued that the first principle of natural law is "do good and avoid evil," and that from this fundamental principle, more specific precepts can be derived, including the preservation of life, the procreation and education of offspring, the pursuit of truth, and the living of society. These precepts are "self-evident" in the sense that they can be grasped by any rational person.

The natural law tradition was further developed by early modern thinkers, most notably John Locke, who transformed natural law into a theory of natural rights. Locke argued that all human beings have natural rights to life, liberty, and property, and that the purpose of government is to protect these rights. This natural rights theory provided the philosophical foundation for the American Declaration of Independence and the Universal Declaration of Human Rights.

Philosophical Perspectives

Natural law theory rests on several philosophical commitments. The first is moral realism: the claim that moral values and duties are objective features of reality, not merely human inventions or social conventions. Natural law theorists argue that just as we can discover the laws of physics through observation and reason, we can discover the moral law through rational reflection on human nature.

The second commitment is a teleological conception of nature. Natural law theory holds that everything in nature has a purpose or end (telos), and that the good for a thing consists in fulfilling its proper function. For human beings, the good consists in living according to reason, which means developing our intellectual and moral virtues and living in community with others.

The third commitment is the unity of practical reason and morality. Natural law theorists argue that the fundamental principles of morality are also the principles of practical reasoning: to act morally is to act rationally, and to act irrationally is to act immorally. This means that the natural law is not an external imposition on human desires but the expression of what human beings truly need to flourish.

The fourth commitment is the connection between law and morality. Natural law theorists argue that the validity of human laws depends, at least in part, on their conformity to the natural law. A law that requires what is fundamentally unjust -- a law that requires the persecution of an innocent minority, for example -- is not a valid law, and citizens have no moral obligation to obey it.

Modern Reflection

Natural law theory has experienced a significant revival in twentieth- and twenty-first-century political philosophy. Thinkers such as John Finnis, Germain Grisez, and Robert P. George have developed "new natural law theory," which defends the natural law tradition using the methods of contemporary analytic philosophy. Finnis, in Natural Law and Natural Rights (1980), argues that the basic goods of human flourishing -- life, knowledge, play, aesthetic experience, friendship, practical reasonableness, and religion -- are self-evident and provide the foundation for a theory of natural law and natural rights.

Natural law theory continues to be influential in debates about human rights, constitutional law, and the limits of state authority. The idea that there are fundamental rights that no government may violate, which is central to modern constitutionalism, has deep roots in the natural law tradition. The Universal Declaration of Human Rights (1948) echoes the natural law language of "inherent dignity" and "inalienable rights" that belong to all human beings "by nature."

Critics of natural law theory argue that it is metaphysically dubious, that it relies on controversial assumptions about human nature and purpose, and that it has been used to justify conservative positions on issues such as sexuality, abortion, and euthanasia. Defenders respond that the natural law tradition provides the most secure foundation for human rights and that the alternative -- legal positivism -- leaves rights vulnerable to the will of the sovereign. The debate between natural law and legal positivism remains one of the most fundamental in legal and political philosophy.