In a nutshell, “Natural Law Theory” is a philosophical system that suggests humanity and nature are designed to operate most effectively when in line with a discernable set of natural moral rules and principles. In Christian circles, these rules are thought to have been woven into the fabric of reality by God. From this premise, thinkers have devised many philosophical systems related to ethics, politics, morality, social life, and law over the centuries.
Thomas Aquinas and Natural Law
The philosophical concept of Natural Law Theory has existed in one form or another for a long time. Aristotle has been credited with being one of the earliest pioneers of the concept. However, the idea really came into its own when a Medieval Monk named Thomas Aquinas began working on it.
Aquinas was born on January 28, 1225, in Roccasecca, Italy. His parents had high hopes for their boy and sent him off to a monastery at an early age to undergo education. Later, he was sent to the university of Naples. Aquinas developed a love for the Greek philosophers, which influenced his work. The writings of Aristotle, in particular, fascinated the philosopher, who studied and lectured on his writing.
History and Idea
Although Natural law theory was born in the world of Greek philosophy, Aquinas is the one who guided it into its theological maturity. Consequently, his version of the Natural Law Theory is by far the most influential. The influence of his ideas stretches far beyond the world of academia. For example, if you are a part of the Catholic Church or major Protestant denominations, then you’re probably already familiar with some Natural Law Theory principles.
Since his day, many philosophers have applied the general principles of the concept to a wide variety of topics. Yet, despite this diversity of work, Aquinas is widely considered to be the central authority on Natural Law.
According to Standford.edu,
“If any moral theory is a theory of natural Law, it is Aquinas’s. (Every introductory ethics anthology that includes material on natural law theory includes material by or about Aquinas; every encyclopedia article on natural Law thought refers to Aquinas.) It would seem sensible, then, to take Aquinas’s natural law theory as the central case of a natural law position.”
The Natural Law Tradition in Ethics
Because Aquinas’ thoughts on Natural Law theory are by far the most pervasive, his system will be the focus of this article.
Aquinas believed that God created the world to function in a certain way and that he gave his creatures a desire or the instincts necessary to fulfill those good functions. For example, veggies are good for rabbits, so they spend their days foraging around the forest floor. Meat is good for tigers, so they are driven to spend their days hunting. Plants cannot live without sunlight, so they are designed to collect or find as much of it as possible.
Aquinas thought all things in nature have good needs and a drive to fulfill them. He believed God created the world to operate in light of “predictable, goal-driven systems whereby life is sustained, and everything functions smoothly.”
He also believed these basic desires were the starting point for all human morality.
The Basic Goods
As for humans, our fundamental good desires are broken down into a group called the basic goods. The basic goods are by far the central topic of debate amongst Natural Law Theorists. However, be that as it may, Aquinas focused on seven: life, procreation, educating offspring, seeking the divine, social life, knowledge, and rational conduct. Other philosophers have created their own unique lists of basic goods; here are some examples.
Grisez 1983 includes self-integration, practical reasonableness, authenticity, justice and friendship, religion, life and health, knowledge of truth, appreciation of beauty, and playful activities.
Finnis 1980 includes life, knowledge, aesthetic appreciation, play, friendship, practical reasonableness, and religion.
Chappell 1995 includes friendship, aesthetic value, pleasure and the avoidance of pain, physical and mental health and harmony, reason, rationality, and reasonableness, truth and the knowledge of it, the natural world, people, fairness, and achievements.
Finnis 1996 affirms a list much like Grisez 1983, but includes in it “the marital good”.
Murphy 2001 includes life, knowledge, aesthetic experience, excellence in work and play, excellence in agency, inner peace, friendship and community, religion, and happiness.
Gomez-Lobo 2002 includes life, the family, friendship, work and play, experience of beauty, theoretical knowledge, and integrity.
Crowe (2019) includes life, health, pleasure, friendship, play, appreciation, understanding, meaning, and reasonableness.
Stanford Encyclopedia of Philosophy: The Natural Law Tradition in Ethics
From The Basic Goods to The Natural Law
By using the basic goods as a starting place, we can use our ability to reason to uncover the Natural Law.
For example, let’s look at Aquinas’ basic good of life. This good can be seen primarily in our instinctive aversion to death.
If you happened across a tiger on a mid-afternoon stroll, would you ask yourself, “Is this tiger the friendly kind of cat, a member of the bouncy pouncy fun fun fun fun fun variety, or the hungry type.” No! Of course you wouldn’t stop to ask yourself ridiculous questions. Like every sane person on planet earth, your fight-or-flight instincts would ignite, forcing your body to preserve your life one way or the other.
From this starting place, we can use our reason to conclude that life has some kind of value. Otherwise, why would God have given us such a strong desire to stay alive? From these observations, we can say that murder would be against Natural Law since it opposes the basic good of preserving life.
In order to strengthen our hypothesis that murder is against Natural Law, we can look at other basic goods to see if it violates them as well.
Working Together
Aside from breaking the good of life, murdering someone would also harm your ability to live in a polite society. I mean.… who wants to live in a neighborhood with a cold-blooded killer walking around? So, murder would violate both the good of social life and life. Many basic goods play off each other in this way, making violations easy to uncover.
Some have suggested that this is the reason why morality looks so similar around the world. God gave us all basic good desires which can only be satisfied in specific, understandable ways.
So, using these basic goods as a starting place and our God-given abilities to reason, we can discover the Natural moral Laws God wove into the fabric of reality.
Natural Law and The Bible
Interestingly enough, Aquinas’ work on natural law theory was not immediately excepted by the Church. Aristotle’s influence caused many to question its Biblical validity. However, these fears were quelled over time, and Thomas Aquinas was accepted as a great Biblical thinker. He was even canonized as a saint in the year 1323.
Although Aquinas took inspiration from Aristotle, he was writing to the rhythm of the Apostles. His view of morality and the Natural Law has some profound roots in the Biblical tradition, which is why it was excepted despite its pagan attachments. The most obvious way the Biblical impact on his work can be seen is in Paul’s letter to the Romans.
Indeed, when Gentiles, who do not have the Law, do by nature things required by the Law, they are a law for themselves, even though they do not have the Law. They show that the requirements of the Law are written on their hearts, their consciences also bearing witness, and their thoughts sometimes accusing them and at other times even defending them.
Romans 2:14-15
This verse is often cited as the central Biblical case for the Natural Law position. However, it’s not the only passage connected to the view.
Before The Law
Another good example is in the fourth chapter of Genesis. In this part of the story, Cain (the son of Adam) is angry with his brother Able. He allows his malice to fester until it evolves into a desire for blood. God appears to Cain and tells him to be careful because “Sin is crouching at the door.” Despite this warning, Cain does the unthinkable and murders his brother.
Contextually, God has not yet given humanity the ten commandments, or any rules regarding morality, for that matter. So, the sin Cain committed was not governed by any recorded heavenly statute or Law. Consequently, it’s sometimes cited as an example of the Natural Law at play.
Final Thoughts
Since the days of Aquinas, Natural Law Theory has dramatically influenced Christian thought. Its fingerprints can be found in the beliefs of every denomination and sect. However, this is not to say that it doesn’t have its detractors. The Philosopher David Hume pushed back on Aquinas’ perspective by pointing out that just because something “Is” a certain way doesn’t mean that it necessarily “Ought” to be done. Others have argued out that basing your moral system on Basic Goods can easily open up a big can of philosophical worms. For example, is someone sinning if they choose not to have children?
Yet, despite its problems, Natural Law theory has stood proudly as one of the most influential, Biblical, and cohesive moral systems for nearly a thousand years.
Sources & Further Reading
- Stanford Encyclopedia of Philosophy: The Natural Law Tradition in Ethics
- Crash Course Philosophy: Natural Law Theory (Video)
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