Natural law might be defined as the assumption of certain basic, transcendent moral principles which should serve as guides for human behavior. What these are, what laws might exist, is open to discussion. Does natural law encompass only the broadest categories like individual liberty or property ownership?[i] Or does it get more specific and define or at least contribute to ethical standards such as care for the destitute and unborn? The scope of natural law’s coverage is open to discussion.

Before that we first need some clarity as to the starting point of natural law. Is natural law (and right) really as “self evident” as the Declaration of Independence states? How did we get there? How does it affect the future.

A Simple Overview

What Natural Law Is Not

Natural law is not the law of nature.[ii] That is, it is not the law of the jungle enhanced for modern man. That thought, common in certain circles, misses the point entirely. It appeals to a simple materialism and avoids the idea of anything transcendent. It leaves humanity as a mere animal, unable to live except by his proclivities. It is in the end no law at all.

What Natural Law Is

For the certain ancient Greeks the principle was this: Natural law is the common set of ethical principles for all of humanity. One might substitute the terms “custom” or “convention” for “law” as  these terms would convey some of the additional weight of the law.[iii]

Aquinas borrowed this principle but instead of making these laws self-existing he made them contingent on God as their Creator.[iv] Natural law is seen by Aquinas as an expression of the character of God. It follows then that natural law is consistent with the revealed law in the Scriptures. For instance, commands to not murder, to not steal, to not be martially unfaithful, and to maintain harmonious familial relationships are almost universal among human beings as well as being part of revealed law.

Kant took this a step further. His categorical imperative (early) says: “Act only in accordance with that maxim through which you can at the same time will that it become a universal law.”[v]  This natural law, of a sort, assumes that the principle is universally useful and applicable. That is, if everybody did it the result would be the same.

There are several issues with Kant’s principle, and it holds for all of his formulations. One of them is this: All of them begin and end with the individual. This is reflective of his ideas on personal knowledge. For Kant, like Plato, understood that knowledge begins and ends with our perceptions of the world around us. We can’t appeal to God because we can’t really know God. We are in the end autonomous beings who are unable to make the requisite connections between our perceptions and the realty that surrounds us.

There are other views on natural law from other regions of the globe.[vi][vii] It is not a specifically European concept. It bears similarity to both the Hellenistic and the Thomistic constructs.

There are some common traits among these theories. One is the assumption that there is some universal law available to be discovered. For any theist this is a possibility. It can dovetail with the principle within revealed truth. It in fact lends support to the revelation, thus serving as an apologetic for it.

But …

The question I ask is a simple one: How do we know? How can we find natural laws that apply to all of humanity? Certainly, universal consensus is not the same as transcendent existence? Just because the world agrees on a principle, stealing is wrong, for example, does not mean that there is a universal principle out there that applies to all. (The Thomistic system would of course allow for this.)

There are too many worldview exceptions. Is it wrong to steal what is not yours? That differs in Islam and Christianity. It differs from what some native Americans practiced. The principle of private property is not a universal.

Is it wrong to kill the innocent? Human sacrifice has been a part many human cultures. To appeal to this as a universal represents the same error. Consensus is being confused with transcendence.

Is not the Universal Declaration of Human Rights a type of natural law? Certainly, the Christian would take great exception to many of its provisions.

Then …

I’m concerned about non-theistic natural law. It tends to be arbitrary. It is arbitrary. It exists as an inheritor of the theism around it and enjoys the moral comforts available. Kant’s imperative could not have occurred in the jungles of Brazil or central Africa. The principles weren’t available. It required a Christian context off which to grow, at least as we think about it in the context of our Christian culture and worldview.

Kant’s imperative shows its arbitrary character in this: Why should I? Why should anyone behave in such a manner? “For human flourishing,” you say? But why should people live such a life? What if a high level of selfishness would in the end create greater human flourishing than the implied selflessness of the imperative? What if the imperatives of Islam, the struggle to spread the law of Allah, would create greater human flourishing? If humans be mere animals then perhaps Camus is right and we deserve no flourishing at all. Kant’s arbitrariness fails the test of reason.

I’m concerned about some theistic approaches to natural law. They can tend to do damage to a proper hermeneutic and thus damage theology. That shows itself as we see how Romans 1 is often mistreated.

Romans 1:19-21 is regularly employed in Christian arguments for natural law (and natural revelation). It is argued that the lost person might find God through nature. That is, be seeing God’s power and then coming to faith. At least potentially. It is argued that because a knowledge of God is available to nature and has been willfully rejected, then one might willfully not reject that knowledge through nature.

There are two problems with this approach. The first is that it treats observed nature as a source for knowledge that might lead one to the creator. It substitutes what might be perceived from the natural world (general revelation) for what is only accomplished through special revelation.  That’s a basic categorical error.

The second follows the first: It guts Paul’s argument in the first two chapters of Romans. By allowing that a person might find God, and thus redemption, by a proper response to the apparent inferences of the natural world the necessity of the work of Christ is at least minimized if not nullified. Can we lead people to Christ by leading them to nature to seek God? If that were the case then Paul would not be arguing in those first two sections of Romans that all of humanity is lost and in need of redemption through the work of Christ.

The implication of this is called “inclusivism.” It is an attempt to answer the question “What if a person, committed to the Most High God like Melchizedek, repents of sin? Will God forgive and redeem that person apart from a knowledge of Christ? Is the foundation of Christ’s sacrifice enough even for those who lack the knowledge of Christ?”

It’s a tough question. There are hard and soft versions of inclusivism. The hard version would say that we don’t need to do evangelism and missions because people everywhere are free to repent and, once they have knowledge of Christ, are in greater danger of condemnation. The soft version says that’s not really true because so very few ever repent that the advance of the gospel remains necessary for the redemption of many more.

This seems an aside from the question of natural law but rather it goes to one of the treatments which is common in evangelical circles. While I remain skeptical on the subject it is clear none the less that a mistreatment of natural law can do theological damage. Some caution is warranted.