Quoting from Crashcourse: “If you are a member of any of the major Protestant denominations, or were raised in any of those traditions, then you are probably already familiar with how (Thomas) Aquinas saw the moral universe and your place in it.”. Thomas Aquinas is the 13th century Italian Christian monk who pioneered the Natural Law Theory (NLT). NLT serves as a more reasonably sound theistic alternative to the Divine Command Theory (DCT); and that’s what we are going to dive into today.

Metaethical Species Moral Absolutism

Basic Assumptions (same as DCT)

1) God exists

2) God is perfect, he is the creator of everything; and he should be revered

Introduction to NLT

Thomas Aquinas was a Christian monk, which explains why he held the above-mentioned assumptions; just like all other devout Christians. However, he did not get his moral values purely from the Bible, because he saw a huge flaw in doing so: Not everyone of us read the Bible. Since God is perfect, he must have given us another way for us to follow his rules other than using the Bible; otherwise God wouldn’t be flawless. Get it? If he is perfect, his plans are perfect; so it’s not possible for him to overlook such a loophole. 

Setting off from this doubt, Aquinas went on to theorize that “God made us pre-loaded with the tools we need to know what’s good. This idea became known as the natural law theory.” (Crashcourse, 2016)

Desire and Instincts

So what exactly are the tools that God pre-loaded us with? Aquinas theorized that these tools that are made into our intelligent design are our basic instincts and desire. What our basic instincts and desires leads us to pursue is a category of desires called “basic goods”, and there are seven of them.

Basic Goods

  1. Self-preservation 
  2. Reproduction
  3. Education of Offsprings
  4. Seek God
  5. Live in Society
  6. Avoid Offense
  7. Shun Ignorance


According to Aquinas, God imbued in us a survival instinct. What’s interesting is that this statement is a reconciliation between science and religion. Survival instinct? Sounds a lot like an element of Darwin’s Theory of Evolution. Most anti-theists would cite this theory to disprove religion. However, what Aquinas is proposing is that religion still makes sense, because God made evolution part of his intelligent design; hence it is a reconciliation. The other basic goods would also make a lot of sense to us; which is why it can be a very appealing ethical theory to practice.


Science has also proven again and again that we seek reproduction. According to Aquinas, that’s why god made sexual intercourse feel good. It’s like an incentive, y’know?

Education of Offsprings

We teach our children stuff so that they do well. We humans will call it parents’ love. But in the case of animals, they also teach their offsprings how to survive. By doing so, they seek to preserve their species; which is in alignment with Darwin’s theory. God gave us this instinct to do so, or so Aquinas said.

Seek God

Have you ever wondered why, despite the foolproof method of science and the microscopic possibility that God exists based on these methods; most of us still believe in God? Aquinas said that it is because we are in-built to seek God. Heck, even the atheist existentialist Jean Paul Sartre agree that there is a god-like hole in all of us. The only difference, though, is that he felt that this hole can never be filled. Aquinas, on the other hand, thought otherwise.

Live in Society

Agreeing with Aristotle, Aquinas also said that we are social animals   . We seek to live alongside each other, because we don’t want to be lonely, because we seek love and acceptance. Makes a lot of sense, don’t you think?

Avoid offense

Aquinas also pointed out that we are rational beings. It is a cold and cruel world out there when we were still at the hunter-gathere stage, hence we seek cooperation to enhance our wellbeing and security. This is the very basic motivation behind the formation of civilizations that we have today. In doing so, we invented “social skills” to facilitate our effort to cooperate. As counter-intuitive as it might sound, on the individual level, we are conflict-adverse.

Shun ignorance 

I’m sure you’ve heard before that we humans are creatures of curiosity, or something like that. It is true, we crave exploration and the discovery of the unknown – which is why Christopher Columbus was so keen on finding America despite the enormous risk of the voyage back then and the multiple failures of those before him. This is also why space exploration became a possibility. This insatiable curiosity is the very spirit of science, and Aquinas theorized that this was in-built in all of us by God himself.

Basic Goods, the Main Attraction Point of NLT

A common trend of the basic goods is that they all makes sense; hence the NLT makes sense as well. NLT makes sense because it fits so well to the world that we know unlike the DCT. DCT based on the Bible and other religious scriptures for moral values, but more often than not; these scriptures are outdated. As I’ve explained in the DCT post, the practicing of DCT would lead us to either regard our whole modern culture as a violation of God’s plan; or it would discredit the very existence of God itself. For NLT, Aquinas proposed a very universal and timeless theory. He based morality on our human nature itself, but because he assumed that human nature is the design of God, NLT indirectly draws its morality from God.

Derivation of Moral Principles

So, how does this all work? How do the basic goods translate to moral code of conducts that we should follow? Simple. We just need to make sure that these basic goods are available to us and others. Take self-preservation for instance: If self-preservation is a basic good that I should have, then I shall never commit suicide. Since basic good also applies to everyone, we should also seek to not hinder everyone else from self-preservation. That means that killing is also prohibited. Similar line of logic can be applied to other basic goods. For reproduction, no abortion, condoms or other contraceptive means. For education of offsprings, letting your child go to school and not dumping them are both morally sound actions. For seeking God, evangelism is encouraged. For living in society, social marginalization and isolationism are morally wrong. For avoiding offense, abuse of any kinds are wrong; and thus promotion of kindness is encouraged. For shunning ignorance, we are encouraged to seek for more knowledge. In the perspective of Aquinas, the best way to do this is to study the Bible. All of these basic goods have both positive and negative injunctions that leads to encouragement and prohibition respectively. For instances, promote life and do not jeopardize life; do procreate and do not use contraceptive means; do send your kids to school and do not dump them; do evangelize and do not promote atheism; do live in community and do not isolate yourself or others; do be polite and do not be rude or insensitive; do seek for more knowledge and do not be a sloth of wisdom. I hope all these explanations helped you to understand how this works. In essence, just follow the golden rule: do unto others what you want others to do unto you.

Challenging the instinct premise of NLT

Like all other ethical theories, the NLT has its own share of criticisms. For one, many would point out that: If God built us with the instinct to do what is morally right, then why are there still so many who violates the NLT? These critics are referring to the existence of murderers, contraceptive users, abortionists, etc. Aquinas had 2 answers for this: ignorance and emotion. Ignorance because we don’t know better, due to our circumstances which lead us to believe that what we are doing is wrong although it violates the NLT. This is why the NLT prohibits atheism and promotes evangelism: he felt that following the NLT can spread the words of god and cure us from ignorance. By extension, we also achieve the final basic good; shunning ignorance. However, ignorance cannot account for all the outliers; emotion is the second answer: we are also emotional creatures on top of rational ones. Hence, sometimes, emotions overpower our reasons; causing us to do things that we know we shouldn’t. This is why we often read the news about a husband or a wife killing his or her partner in a fit of rage. It happens. God is perfect, but he did not make us perfect; or else we would be Gods.

Hume’s rebuttal using the is-ought problem

David Hume was an 18th century Scottish philosopher. He claimed that “it is fallacious to assume that just because something is a certain way, that means that it ought to be that way. But that’s basically what natural law theory does all day long. We look at nature and see that creatures have strong survival instincts, so from there we conclude that survival instincts are good.” (Crashcourse, 2016). This is-ought problem is not only downplay the NLT as a product of fallacy in itself, but also raises 2 very huge problems as I see it: contradiction of self vs others & convenient style of reasoning.

Contradiction of self vs others

So we know that we must preserve life, and there are 2 sides to this: preserve your own life and others’ lives. What if you are forced to make a choice, a dilemma between taking your own life and others? What if you are about to starve to death in the middle of the ocean on a boat with your partner and the only way for you to survive is to either kill him and eat his flesh (because he is definitely going to try to eat you and not be willing to share his flesh) or let him eat you?  You will still die of hunger even if you surrender your flesh. NLT doesn’t have a clear-cut answer to this; and so it is a flaw. Nonetheless, it is but a small flaw as these dilemmatic situations are rare.

Convenient Style of Reasoning

If you think about how Aquinas came up with this theory, you will realize that there is a deeper problem than the is-ought problem. Aquinas made observation of what is the reality, and then came up with a theory to flexibly and conveniently fit the reality that we all know – which is why it makes a lot of sense. The problem, though, is that it is a theory that can never be disproven. Although it is the scientific method to use observations to form hypothesis, the next step is usually with experimentations that seek to disprove the theory: which is why Einstein spent his entire life observing the universe or solar eclipses; seeking to disprove his Theory of General Relativity. However, this theory is different; it runs on the assumption that makes the source of confirmation arbitrary: God exists and he wills whatever  Aquinas said. Aquinas can come up with anything at all, using any convenient form of reasonings to fit the reality. Whatever he theorizes, he can simply claim that it is what God wants. Admittedly, this is an ethical theory and should not be scrutinized in the scientific way. However, for any scientific practitioner out there; this theory is going to be hard to swallow: because everything about this theory just seems too convenient to be true.


The NLT is a theistic ethical theory that suggests that we are all perfectly designed by a perfect God to be pre-loaded with moral values . These values come in the form of our desires and instincts called basic goods. Using logic, these basic goods can help us derive moral principles to guide our actions. Although the instinct premise of the NLT was challenged, Aquinas provided reasonable explanations to the outliers pointed out as part f the challenge. Nonetheless, the theory is not going to appeal to those who: agree with David Hume on the Is-ought problem, are not theists, and are scientific practitioners. Nevertheless, for the others; it remains a viable and useful ethical theory to uphold. In the next post, I will move on to Kantianism and Categorical Imperatives; an agnostic alternative to the NLT & DCT.

Signing off,



Crash Course YouTube Video: Natural Law Theory: Crash Course Philosophy #34 


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