What would an updated natural law ethic look like?

Natural law can still serve the common good and human flourishing—if it catches up with contemporary science and the church’s social teaching.
Peace & Justice

When St. Paul wrote, in his letter to the Romans, about a “law written on the hearts” of the Gentiles, he wasn’t just using a fanciful metaphor or trying to ingratiate himself with non-Jews. He was referencing an idea that already existed among pre-Christian philosophers such as Aristotle and Cicero: a moral law distinct from either religious or civil law and discernible by human reason.

But we can thank St. Thomas Aquinas for the widespread application of natural law in philosophy, theology, and jurisprudence today. Aquinas was the one who developed a systematic approach to the idea. This guided the medieval church in articulating God’s providential plan for every person to flourish in their lives on Earth and their future happiness in heaven.

Eight centuries later, we understand natural law to refer to an approach to ethics which evaluates right and wrong, good and evil based on accurate observation of humans and our place in nature.  But it’s become harder to determine how the natural law tradition can serve people living in the rapidly changing and alarmingly fragile global civilization of today. Not only has our conception of human flourishing developed considerably; it’s also increasingly difficult to find a consensus on what flourishing even entails.

In the Middle Ages, to flourish meant certain very basic things: having access to food, water, and shelter. It meant protection by rulers from outside invasion and internal strife, as well as just laws for the preservation of order. And at the foundation of society was the freedom men and women had to marry and procreate and to raise children who would survive and in their turn flourish and sustain the community.


When we discuss human flourishing today, we mean more than this. We now include the rights of every person to have access to public education (at least through the end of high school), offering the opportunity to learn a trade or master an intellectual profession by which to earn a living and support a family and community. Especially true in the history of the United States, we acknowledge the right to own property and the freedom to practice one’s religion (or none); the freedom to travel and to move about freely at least within the country of one’s origin in order to attain education and employment. Only recently have we championed the rights of all to basic health care and public support for facilities designed to accommodate people who suffer from lifelong disabilities.

In short, human flourishing today assumes a greater sense of both individual autonomy and of community responsibility, neither of which classical natural law theory in its most popular incarnations fully appreciates. Natural law has come to be associated with outmoded ideas about the person, especially in areas of gender and sexuality. Given our contemporary understanding of human flourishing—in individuals, in relationships, in communities—it’s no wonder that some might want to jettison natural law theory as irrelevant or even harmful. At the same time, natural law theory has been updated repeatedly in the past and often applied in the cause of justice. British philosopher John Locke used natural law to argue for an early version of gender equality, for instance. So why couldn’t natural law be put in the service of a more accurate understanding of humans and community?

One issue with the older ideas of natural law was that human freedom was never a key component. As scholars have noted, Aquinas was content to adopt Aristotle’s defense of slavery as a natural feature of human society. His regard for the abilities and the rights of women was similarly inadequate. Older versions of natural law often failed to consider the inequities that arose for the poorest who were shut out of access to the prosperity of the growing merchant class.

Today, we understand flourishing as more than just having access to basic material needs. We also recognize freedom, liberation, and autonomy as essential to the well-being of the person. And technology has also influenced our understandings of what it means to live a good life, or to uphold the common good, to guarantee the rights and safety of all laborers. Advances in medicine dramatically reduced infant mortality and maternal death. Improvements in machinery, agriculture, food production, international commerce, and the exploration and colonization of the wider world allowed whole nations of people to flourish in ways they never had before.


Medical progress has offered humanity more precise control over procreation and more choice in sexual expression for men and women. This is an important point in an era when humanity has expanded to the point of a worldwide population exceeding 8 billion people, threatening the life balance of the entire planet. An understanding of natural law that is more in tune with the scientific understanding of human sexuality and reproduction—particularly as it has been broadened over the past century—would allow for a more thoughtful approach to family planning at the level of society as well as at the basic level of the family unit. This would include a broader appreciation for the equality of women and their rights as caregivers and workers in the home, as well as the rights of children at all stages of development.

But there remain great shortfalls. The idea of promoting literacy and public education never entered the minds of medieval rulers or the monasteries where education was reserved for the men entering the religious life. Now education is crucial for anyone who wants to thrive in a global economy increasingly dominated by technology. Yet access to education remains out of reach for many. This is most painfully evident in regions of the United States where the relocation of manufacturing jobs over the past four decades has left an entire generation of middle-class Americans with no alternative career path and little support for supplemental education. This is even more evident in the poorer nations of the global south, where, often without support from the government, religious orders of nuns and priests often devote their lives to serving the poorest in remote communities far from urban centers.

The challenge facing ordinary people now is not the fear of lawlessness (although in the poorer countries of the world, this is a still a real threat). It’s the fear of business leaders who exploit the laws of their own countries and others to enrich themselves at the expense of the poorest. In Hungary, for example, the political program of President Viktor Orban seems designed to follow the blueprint of Putin’s Russia, where public utilities were privatized and turned over to the enrichment of political cronies. In the case of Russia, this left the people more impoverished than ever, as prospects for political and religious freedom were crushed and an entire generation subject to military conscription to feed Putin’s imperialist ambitions. This kind of crony monopolizing has created what critics regard as a pernicious form of techno-feudalism, where even in western democracies consumers are forced to pay what the only provider in the market demands.

A new approach to natural law must include stronger support for economic and social justice if it is to be compelling. Pope Francis has clearly suggested this in his encyclical Laudato Si’ (On Care for our Common Home), insisting that a global perspective is essential to how we define our place in creation.


To date, however, defenders of natural law are mainly to be found among traditionalist Catholic scholars and theologians, few of whom acknowledge science’s role in our understanding of human nature and the global environment. Nor do many accept that natural law can make sense apart from a religious perspective. It’s perhaps ironic that, in spite of this limitation, Catholic social teaching is much more in tune with the global needs and concerns of everyday Catholics than natural law tradition.

What would a newer understanding of natural law entail? What are some principles it might build on? First: Reason—the birthright of every human being. This is so fundamental it goes back to Aristotle, who said that all men naturally desire to know. And this reinforces the principle that education should be considered a natural right (along with health care).

It should also stress political engagement based on human rather than narrowly religious concerns—on freedom and social and economic justice. This includes reassessing how natural law has been used to block access to birth control or oppose LGBTQ+ rights. Finally, a broader application of natural law would emphasize humanity’s membership in a global community, and our responsibility to our global home. This would include a more conscious awareness of how technology has polluted and degraded the environment.

More broadly, and catching up with the church’s own social teaching which has developed over the last century, a revised natural law should reinforce the grounds for opposing all racism and champion the rights of immigrants the world over—in particular those driven from their homelands, especially those threatened by political persecution or the harsh conditions wrought by climate change.


If more Catholic scholars reconsidered natural law with these principles in mind, what a difference it could make. If, on the other hand, the Catholic natural law tradition remains a tool for enforcing a narrow view of human nature and a static view of creation, it will do little to serve human flourishing.

Image: Wikimedia Commons/Aristotle tutors Alexander the Great


About the author

John W. Farrell

John W. Farrell is the author most recently of The Clock and the Camshaft: And Other Medieval Inventions We Still Can’t Live Without. He has written for Commonweal, Aeon, New Scientist, The Wall Street Journal, Salon, Forbes, and The Tablet.

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