Natural Law: Definition and Application

Declaration of Independence

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Natural law is a theory that says all humans inherit—perhaps through a divine presence—a universal set of moral rules that govern human conduct.

Key Takeaways: Natural Law

  • Natural law theory holds that all human conduct is governed by an inherited set of universal moral rules. These rules apply to everyone, everywhere, in the same way.
  • As a philosophy, natural law deals with moral questions of “right vs. wrong,” and assumes that all people want to live “good and innocent” lives.
  • Natural law is the opposite of “man-made” or “positive” law enacted by courts or governments.
  • Under natural law, taking another life is forbidden, no matter the circumstances involved, including self-defense.

Natural law exists independently of regular or “positive” laws—laws enacted by courts or governments. Historically, the philosophy of natural law has dealt with the timeless question of “right vs. wrong” in determining the proper human behavior. First referred to in the Bible, the concept of natural law was later addressed by the ancient Greek philosopher Aristotle and Roman philosopher Cicero

What Is Natural Law?

Natural law is a philosophy based on the idea that everyone in a given society shares the same idea of what constitutes “right” and “wrong.” Further, natural law assumes that all people want to live “good and innocent” lives. Thus, natural law can also be thought of as the basis of “morality.” 

Natural law is the opposite of “man-made” or “positive” law. While positive law may be inspired by natural law, natural law may not be inspired by positive law. For example, laws against impaired driving are positive laws inspired by natural laws.

Unlike laws enacted by governments to address specific needs or behaviors, natural law is universal, applying to everyone, everywhere, in the same way. For example, natural law assumes that everyone believes killing another person is wrong and that punishment for killing another person is right. 

Natural Law and Self Defense

In regular law, the concept of self-defense is often used as justification for killing an aggressor. Under natural law, however, self-defense has no place. Taking another life is forbidden under natural law, no matter the circumstances involved. Even in the case of an armed person breaking into another person’s home, natural law still forbids the homeowner from killing that person in self-defense. In this way, natural law differs from government-enacted self-defense laws like so-called “Castle Doctrine” laws. 

Natural Rights vs. Human Rights

Integral to the theory of natural law, natural rights are rights endowed by birth and not dependent on the laws or customs of any particular culture or government. As stated in the United States Declaration of Independence, for example, the natural rights mentioned are “Life, Liberty, and the Pursuit of Happiness.” In this manner, natural rights are considered universal and inalienable, meaning they cannot be repealed by human laws.

Human rights, in contrast, are rights endowed by society, such as the right to live in safe dwellings in safe communities, the right to healthy food and water, and the right to receive healthcare. In many modern countries, citizens believe the government should help provide these basic needs to people who have difficulty obtaining them on their own. In mainly socialist societies, citizens believe the government should provide such needs to all people, regardless of their ability to obtain them.

Natural Law in the US Legal System

The American legal system is based on the theory of natural law holding that the main goal of all people is to live a “good, peaceful, and happy” life, and that circumstances preventing them from doing so are “immoral” and should be eliminated. In this context, natural law, human rights, and morality are inseparably intertwined in the American legal system. 

Natural law theorists contend that laws created by the government should be motivated by morality. In asking the government to enact laws, the people strive to enforce their collective concept of what is right and wrong. For example, the Civil Rights Act of 1964 was enacted to right what the people considered to be a moral wrong—racial discrimination. Similarly, the peoples’ view of enslavement as being a denial of human rights led to ratification of the Fourteenth Amendment in 1868. 

Natural Law in the Foundations of American Justice

Governments do not grant natural rights. Instead, through covenants like the American Declaration of Independence and the U.S. Constitution, governments create a legal framework under which the people are permitted to exercise their natural rights. In return, people are expected to live according to that framework.

In his 1991 Senate confirmation hearing, U.S. Supreme Court Justice Clarence Thomas expressed the widely shared belief that the Supreme Court should refer to natural law in interpreting the Constitution. “We look at natural law beliefs of the Founders as a background to our Constitution,” he stated. 

Among the Founders who inspired Justice Thomas in considering natural law to be an integral part of the American justice system, Thomas Jefferson referred to it when he wrote in the first paragraph of the Declaration of Independence:

“When, in the course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the laws of nature and of nature’s God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.”

Jefferson then reinforced the concept that governments cannot deny rights granted by natural law in the famous phrase: 

“We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable rights, that among these are life, liberty, and the pursuit of happiness.” 

Natural Law in Practice: Hobby Lobby vs. Obamacare

Deeply rooted in the Bible, natural law theory often influences actual legal cases involving religion. An example can be found in the 2014 case of Burwell v. Hobby Lobby Stores, in which the U.S. Supreme Court ruled that for-profit companies are not legally obligated to provide employee health care insurance that covers expenses for services that go against their religious beliefs.

Activists hold signs outside the Supreme Court March 25, 2014 in Washington, D.C.  BRENDAN SMIALOWSKI / Getty Images

The Patient Protection and Affordable Care Act of 2010—better known as “Obamacare”—requires employer-provided group health care plans to cover certain types of preventative care, including FDA-approved contraceptive methods. This requirement conflicted with the religious beliefs of the Green family, owners of Hobby Lobby Stores, Inc., a nationwide chain of arts and crafts stores. The Green family had organized Hobby Lobby around their Christian principles and had repeatedly stated their desire to operate the business according to Biblical doctrine, including the belief that any use of contraception is immoral. 

In 2012, the Greens sued the U.S. Department of Health and Human Services, claiming that the Affordable Care Act’s requirement that employment-based group health care plans cover contraception violated the Free Exercise of Religion Clause of the First Amendment and the 1993 Religious Freedom Restoration Act (RFRA), that “ensures that interests in religious freedom are protected.” Under the Affordable Care Act, Hobby Lobby faced significant fines if its employee health care plan failed to pay for contraceptive services.

In considering the case, the Supreme Court was asked to decide if the RFRA allowed closely held, for-profit companies to refuse to provide its employees with health insurance coverage for contraception based on the religious objections of the company’s owners. 

In a 5-4 decision, the Supreme Court held that by forcing religion-based companies to fund what they consider the immoral act of abortion, the Affordable Care Act placed an unconstitutionally “substantial burden” on those companies. The court further ruled that an existing provision in the Affordable Care Act exempting non-profit religious organizations from providing contraception coverage should also apply to for-profit corporations such as Hobby Lobby.

The landmark Hobby Lobby decision marked the first time the Supreme Court had recognized and upheld a for-profit corporation’s natural law claim of protection based on a religious belief.

Sources and Further Reference

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Longley, Robert. "Natural Law: Definition and Application." ThoughtCo, Dec. 6, 2021, Longley, Robert. (2021, December 6). Natural Law: Definition and Application. Retrieved from Longley, Robert. "Natural Law: Definition and Application." ThoughtCo. (accessed May 28, 2023).