A “higher law” that, according to some political philosophers, applies to all human beings everywhere, is discoverable by reason alone, and is a standard by which to evaluate the laws made by human beings.

Natural law is best understood in contrast to positive law and to divine law. Positive law is that made by human beings; it may differ widely from one society to the next. Divine law is that set down in religious teachings; it often strongly influences the laws made by human beings and is said to be knowable only through revelation.

The concept of natural law that has most influenced American law was developed by political philosopher John Locke, pictured here.

(Library of Congress)

According to philosophers, natural law, unlike divine law, is knowable through the use of reason alone, via the human ability to reflect on the nature of the world and on other people. Because nature is universal, natural law is universal. It therefore stands as a body of “higher law” in relation to the laws made by human beings. According to the doctrine of natural law, positive law is just or morally right to the extent that it reflects the natural law.

Although the idea of natural law was first elaborated by the ancient Greeks and Romans and given its fullest premodern expression in the philosophy of the medieval philosopher Saint Thomas Aquinas, the concept of natural law that most affected U.S. jurisprudence derives primarily from the political philosophy of John LockeLocke, John. Together with other Enlightenment philosophers such as Thomas Hobbes,Hobbes, Thomas Samuel von Pufendorf, and Hugo Grotius, Locke transformed the classical and medieval understandings of natural law. This transformation was made possible on the basis of a fundamentally new conception of nature and its relationship to the human world of politics.

Ancient and medieval political philosophy shared the view that human beings are by nature political animals. Modern political philosophy, beginning with Niccolò Machiavelli and Hobbes, broke with this view, arguing that human beings are not naturally political. According to Hobbes, for example, life in the state of nature is “solitary, poor, nasty, brutish, and short.” In the state of nature, no sovereign exists; each person must compete against all others. Competition, scarcity, the desire for glory, and fear for one’s life make existence in the natural state terrifying. Although people are free in the state of nature to do what they desire, they cannot possibly enjoy this unlimited freedom. They have rights natural rights in the state of nature, but they cannot enjoy them. Therefore, they consent to form a “social compact”; they give up their unlimited freedom to be ruled in civil society so that they might enjoy a prosperous peace and comfortable self-preservation. People’s natural desire to preserve themselves is thus fulfilled in the most rational manner possible by following what Locke termed the “first and fundamental natural law.” This law commands the preservation of the society and everyone in it. Even the sovereign power that makes human laws is governed by this natural law.

The concept of natural law finds expression in the opening sentence of the Declaration of IndependenceDeclaration of Independence (1776), which justifies the American Revolution in terms of an appeal to “the laws of nature and of nature’s God.” Following the philosophy of Locke, the laws of nature are transformed into natural rights: All human beings are endowed with the inalienable rights to life, liberty, property, and the pursuit of happiness, and all are equal insofar as they possess these inalienable rights. The purpose of government is to protect people’s rights, and all legitimate government is based on the consent of the governed.

The idea of a body of “higher law,” whether it takes the form of natural laws or natural rights, has been powerfully influential in U.S. jurisprudence, particularly in the context of interpreting the vague due process and equal protection clauses of the Fourteenth Amendment.Constitutional interpretation In a number of famous cases, particularly Calder v. Bull[case]Calder v. Bull[Calder v. Bull] (1798) and Adamson v. California[case]Adamson v. California[Adamson v. California] (1947), the Supreme Court debated whether there is any “higher law” or are any “principles of natural justice” that should determine how the Constitution is to be interpreted. The issue was also hotly debated in the 1991 Senate hearings to confirm Court nominee Clarence Thomas. The issue of the existence of a “higher law” raises the question of how much latitude the Court has to read substantive moral values into the Constitution. Critics of the idea of a “higher law” interpretation of the Constitution fear that such a doctrine would allow justices to read their own moral values into the Constitution and would make the judiciary too powerful in its ability to override the will of the people as expressed by their national and state governments.

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• Arkes, Hadley. Beyond the Constitution. Princeton, N.J.: Princeton University Press, 1990.
• Berns, Walter. “Judicial Review and the Rights and Laws of Nature.” In The Supreme Court Review 1982, edited by Phillip Kurland, Gerhard Casper, and Dennis Hutchinson. Chicago: University of Chicago Press, 1983.
• Corwin, Edward S. The “Higher Law” Background of American Constitutional Law. Ithaca, N.Y.: Cornell University Press, 1955.
• Fried, Charles. Saying What the Law Is: The Constitution in the Supreme Court. Cambridge, Mass.: Harvard University Press, 2004.
• Gerber, Scott. To Secure These Rights: The Declaration of Independence and Constitutional Interpretation. New York: New York University Press, 1995.
• Grey, Thomas. “Do We Have an Unwritten Constitution?” Stanford Law Review 27 (1975): 703.
• Locke, John. Essays on the Law of Nature. Oxford: Clarendon Press, 1954.
• Ritchie, Donald A., and JusticeLearning.org. Our Constitution. New York: Oxford University Press, 2006.
• Willoughby, Westel Woodbury. The Supreme Court of the United States: Its History and Influence in Our Constitutional System. Union, N.J.: Lawbook Exchange, 2001.

Adamson v. California

British background to U.S. judiciary

Calder v. Bull

Declaration of Independence

Fourteenth Amendment

Judicial activism

Rule of law

Thomas, Clarence