91. Martin Luther King, Jr. and Natural Law

Martin Luther King, Jr., in his “Letter from a Birmingham Jail” (April 16, 1963), asserts that segregation, far from being only politically, economically, and sociologically unsound, is also morally wrong insofar as it “distorts the soul and damages the personality.” He justifies this remarkable claim with reference to natural law. Consider this excerpt:

“I would agree with St. Augustine that “an unjust law is no law at all.” Now, what is the difference between the two? How does one determine whether a law is just or unjust? A just law is a man made code that squares with the moral law or the law of God. An unjust law is a code that is out of harmony with the moral law. To put it in the terms of St. Thomas Aquinas: An unjust law is a human law that is not rooted in eternal law and natural law. Any law that uplifts human personality is just. Any law that degrades human personality is unjust. All segregation statutes are unjust because segregation distorts the soul and damages the personality.”

Here we see King appealing to natural law theory to rationally justify his views against segregation. Rather than appeal to self-evident truths, feelings, habits, or some form of authority, King argues that segregation is immoral because it violates a natural moral law. But what is natural law theory? And how can we use it to show that segregation, as King says, distorts the soul? These are the two questions I want to answer. To anticipate, we will see that segregation is immoral insofar as it hinders rather than helps the development of our rational and social nature.

The Basics of the Theory

The origins of natural law theory can be traced back to ancient philosophers such as Heraclitus, Plato, Aristotle, Marcus Aurelius, and Cicero who employed ideas central to it. It was then developed by medieval thinkers such as Tertullian, Justinian, and St. Augustine. But the first comprehensive formulation of the theory appears in the writings of the medieval philosopher St. Thomas Aquinas. Natural law theory is then subsequently developed over the centuries in various directions, many theistic, some more secular in nature. Figures as diverse as Moses Maimonides, Francisco Suarez, Thomas Hobbes, Hugo Grotius, and John Locke made substantial philosophical contributions to its development. And the tradition continues to thrive in contemporary philosophy, political action, law, and religion.

The details of this diverse history are complex. But the basic ideas are straightforward and powerful. According to most versions of natural law theory, we begin by recognizing certain good potentials of human nature (to be rational, social, loving, friendly, creative, free, responsible, kind, etc.). This recognition can come about just using our reason—we don’t need revelation from God or any mysterious capacities or talents. We then judge actions to be right if they facilitate the actualization of these potentials and wrong if they thwart them. Action can then be both guided and judged by articulating natural moral laws that prescribe how we should act rather than just describe how we do act. These laws, being grounded in our shared humanity, hope to be universal (they would apply everywhere at all times), objective (not only a matter of personal or cultural opinion), and intelligible (capable of being rationally understood either immediately or after careful consideration). Once we have natural laws we can use them to justify natural rights. Natural rights will be those things that are essential to us if we are to realize our good natural potentials. Natural rights, just like natural laws, are not contingent on the decisions of a particular society like civil rights are. Rather, they are inalienable and necessary if our natural potentials are to be actualized at all (if you want a more thorough overview of natural law theory, go here).

Before turning to King’s use of the theory, let’s consider a plausible example to make things less abstract. Aristotle (322-384 BC) argued that to fully understand something it is necessary to understand its natural purpose or essential function (telos). In Book I of his Nicomachean Ethics, Aristotle argues that humankind’s natural purpose is reason. It is the one trait unique to us and definitive of our nature. But if reason is our defining characteristic—our essence—then our natural purpose, according to Aristotle, is to actualize this potential reason as much as possible in the form of moral and intellectual virtue. By doing so we can become fully actualized human beings and reach happiness or fulfillment (eudaimonia). Now once this view of human nature is in place we can formulate the following natural moral law:

NML: We should all develop our rational capacities.

Again, according to natural law theory we begin by recognizing certain good potentials of human nature and then judge actions to be right if they facilitate the actualization of this potential. In this case, we have the recognition of a natural good we possess—the potential to reason—and then we have a moral prescription of right action based on that recognition. Far from being just a scientific description of what we in fact are—rational animals—it goes on to provide a moral prescription. This prescription can lead to concrete ways to guide our behavior and evaluate our motivations, the acts that follow from these motivations, and the consequences that follow from our acts. For example, we could argue that everyone should get educated and should have a right to education. After all, one of the bad consequences of not getting educated is that it prevents the realization of our rational nature. Moreover, any motive to prevent education would be bad and any act thwarting education would be wrong. Thus we could articulate a second natural moral law that includes a natural right:

NML: Everyone should get educated and should have a right to education.

We could also argue that people shouldn’t grow up in a totalitarian regime where dissent is crushed and propaganda replaces the truth. After all, such a society would be bad insofar as truth and free debate are integral to the development of reason. And we could argue that forms of abuse (child abuse, substance abuse, and so on) that impair the proper function of the brain are wrong as well. Of course, there are plenty of other good capacities of human nature that we could discuss. For example, our capacities for life, liberty, the pursuit of happiness, friendship, love, creativity, aesthetic appreciation, humor, hope, wonder, sympathy, play, and justice could be our focus and we could formulate moral prescriptions based on them as well.

Naturally, many questions can be raised here: do we even have universally and naturally good traits? Doesn’t the diversity of culture and widespread moral disagreement show we don’t? If we do, what exactly are these naturally good traits? Who gets to decide what they are? Can these traits change? Can we really infer moral prescriptions from descriptions about our nature? These are important questions and they often generate substantial controversy. But let’s set them aside for now and turn to King’s application of the theory.  

Martin Luther King, Jr. and Natural Law

Throughout history there are many examples of people appealing to a deeper, moral order in their efforts to criticize the unjust laws and practices of their time. Civil laws are made by particular people in particular societies. But if a certain society disintegrates then the civil laws of that society may or will disappear. Not so with natural laws: they exist independent of our wishes and decisions and provide a ground for morality that is universal, objective, and intelligible. As such, a natural law can be a powerful platform from which to morally and rationally criticize various unjust social practices. For example, Charles Henry Langston (1817–1892), an American abolitionist and political activist, was one of a group of men who freed runaway slave John Price in 1858. The Underground Railroad hid Price in Oberlin and helped transport him to freedom in Canada. Eventually, Langston was tried and convicted. But he thought he stood on a moral law deeper than the prevailing civil laws. Consider his words at the Cuyahoga Courthouse, May 1859: “I stand here to say that I will do all I can, for any man thus seized and help, though the inevitable penalty of six months imprisonment and one thousand dollars fine for each offense hangs over me! We have a common humanity.” 

Charles Langston (1817-1892)

Here we see a common theme of natural law theory at work, namely, our common humanity. This theme played a crucial role in the decisive Nuremberg Trials as well. Barbara MacKinnon explains:

“The Nuremberg trials were trials of Nazi war criminals held in Nuremberg, Germany, from 1945 to 1949. There were thirteen trials in all. In the first trial, Nazi leaders were found guilty of violating international law by starting an aggressive war…in other trials, defendants were accused of committing atrocities against civilians…The defense contended that the military personnel, judges, and doctors were only following orders from their superiors in the Nazi regime. However, the prosecution argued successfully that that even if the experimentation did not violate the defendant’s own laws, they were still “crimes against humanity.” The idea was that a law more basic than civil laws exists—a moral law—and these doctors and others should have known what this basic moral law required.”

A photo from the Nuremberg Trials.“The main target of the prosecution was Hermann Göring (left), considered to be the most important surviving official in Nazi Germany.” (Wikipedia)

And King explicitly employed natural law theory in his “Letter from a Birmingham Jail” to justify his position against segregation when according to the law his actions were wrong. Recall he ended up in the Birmingham jail because he was non-violently opposing segregation. As a result, he couldn’t appeal to the law to make his moral case. Rather, he used natural law theory to make a moral case in support of his actions. Consider this more substantial excerpt:

First edition (1963) published by American Friends Service Committee

“Since we so diligently urge people to obey the Supreme Court’s decision of 1954 outlawing segregation in the public schools, at first glance it may seem rather paradoxical for us consciously to break laws. One may well ask: “How can you advocate breaking some laws and obeying others?” The answer lies in the fact that there are two types of laws: just and unjust. I would be the first to advocate obeying just laws. One has not only a legal but a moral responsibility to obey just laws. Conversely, one has a moral responsibility to disobey unjust laws. I would agree with St. Augustine that “an unjust law is no law at all.” Now, what is the difference between the two? How does one determine whether a law is just or unjust? A just law is a man made code that squares with the moral law or the law of God. An unjust law is a code that is out of harmony with the moral law. To put it in the terms of St. Thomas Aquinas: An unjust law is a human law that is not rooted in eternal law and natural law. Any law that uplifts human personality is just. Any law that degrades human personality is unjust. All segregation statutes are unjust because segregation distorts the soul and damages the personality. It gives the segregator a false sense of superiority and the segregated a false sense of inferiority. Segregation, to use the terminology of the Jewish philosopher Martin Buber, substitutes an “I it” relationship for an “I thou” relationship and ends up relegating persons to the status of things. Hence segregation is not only politically, economically and sociologically unsound, it is morally wrong and sinful. Paul Tillich has said that sin is separation. Is not segregation an existential expression of man’s tragic separation, his awful estrangement, his terrible sinfulness? Thus it is that I can urge men to obey the 1954 decision of the Supreme Court, for it is morally right; and I can urge them to disobey segregation ordinances, for they are morally wrong…. We should never forget that everything Adolf Hitler did in Germany was “legal” and everything the Hungarian freedom fighters did in Hungary was “illegal.” It was “illegal” to aid and comfort a Jew in Hitler’s Germany. Even so, I am sure that, had I lived in Germany at the time, I would have aided and comforted my Jewish brothers. If today I lived in a Communist country where certain principles dear to the Christian faith are suppressed, I would openly advocate disobeying that country’s antireligious laws.” (read the whole letter here)

Here we see King advocates resisting the injustice of segregation on the basis of a natural moral law. Segregation, in violating this law, “distorts the soul” and is therefore immoral. But what exactly is this law? And how exactly would violating it distort the soul? It isn’t completely clear from his letter. So let’s take a closer look and see if we can piece together a convincing interpretation.

We can begin by exploring King’s reference in his letter to the prominent twentieth century philosopher, religious thinker, political activist and educator Martin Buber (1878-1965). Buber argued, in his work classic work I and Thou (1923), that an “I-It” relation is very different from an “I-Thou” one. Sarah Scott, in her entry on Buber in The Internet Encyclopedia of Philosophy, gives a helpful overview of the distinction:

“The “I-Thou” relation is the pure encounter of one whole unique entity with another in such a way that the other is known without being subsumed under a universal. Not yet subject to classification or limitation, the “Thou” is not reducible to spatial or temporal characteristics. In contrast to this the “I-It” relation is driven by categories of “same” and “different” and focuses on universal definition. An “I-It” relation experiences a detached thing, fixed in space and time, while an “I-Thou” relation participates in the dynamic, living process of an “other”. Buber characterizes “I-Thou” relations as “dialogical” and “I-It” relations as “monological.” In his 1929 essay “Dialogue,” Buber explains that monologue is not just a turning away from the other but also a turning back on oneself (Rückbiegung). To perceive the other as an It is to take them as a classified and hence predictable and manipulable object that exists only as a part of one’s own experiences. In contrast, in an “I-Thou” relation both participants exist as polarities of relation, whose center lies in the between (Zwischen).”

Martin Buber (1878-1965)

Let’s try and unpack this a bit. When I relate to something as an “it”—say a chair—I see the chair

(1) as a thing that I experience as detached from me that
(2) I can label with the universal term “chair” that
(3) can be manipulated and predicted and
(4) typically leaves me as I am.

When we relate to others as “thous”, however, we see others as

(1) free subjects with whom we participate through dialogue that
(2) defy labels insofar as they are unique and
(3) can’t be manipulated since we are not experiencing them in a detached manner leading to
(4) mutual transformation rather than both parties remaining relatively unaffected.

If we follow Buber’s position, we can see that the racist who advocates segregation

(1) sees the Black person as a detached thing in his spatial and temporal experience that can
(2) easily be labeled (as different, inferior, inhuman, etc.) and
(3) manipulated (slavery, segregation, etc.) and predicted (to do bad, to be unintelligent, etc.) thus
(4) leaving the racist and Black person exactly as they were: the racist remains the “same” “superior” person; the Black person remains the “different” “inferior” one.

King thinks the I-It relations the racist establishes are immoral. And he wants to say they are immoral since they violate a natural moral law. But one connection is still missing: we need to show that I-Thou relations are an extension of our human nature in some sense. Once we do, we can use natural law theory to show that segregation, in substituting I-It relations for I-Thou relations, is thwarting this nature and is therefore immoral. But why should we think I-Thou relations are an extension of our nature? I think one promising approach to this question is to show how I-Thou relations are akin to personhood relationships that, in turn, are natural developments of our rational and social nature. Consider this passage from philosopher Roger Scruton’s book An Intelligent Person’s Guide to Philosophy (Penguin, 1999):

“Human beings are social animals; but not in the way in which dogs, horses, and sheep are social animals. They have intentions, plans, and schemes; they identify themselves as individuals, with a unique relation to the surrounding world. They are, or believe themselves to be, free, and their choices issue from rational decision-making in accordance with both long-term and short-term interests.” (p. 66)

Here we see Scruton, following Aristotle and Aquinas, affirming that humans are social and rational animals. If this affirmation is true, then we have the following natural moral law:

NML: We should all develop our rational and social capacities.

Scruton then goes on to link the social and rational dimension of human nature to personhood. In doing so, he helps us see how, on the one hand, King’s I-Thou vision of humans in dialogue is essential to personhood—something inevitable if one is to function as a person at all—and, on the other hand, that the development of personhood would be the natural development of our rational and social natures. He writes:

“The concept of the person should be seen in the light of this. It denotes potential members of a free community—a community in which the individual members can lead a life of their own. Persons live by negotiation, and create through personal dialogue the space which their projects require. Such dialogue can proceed only on certain assumptions, and these assumptions show us what persons really are [my emphasis]:

1) Both parties to the dialogue must be rational—that is, able to give and accept reasons for action, and to recognizes the distinction between good and bad reasons, between valid and invalid arguments, between justifications and mere excuses.

2) Both parties must be free—that is, able to make choices, to act intentionally in pursuit of their goals, and to take responsibility for the outcome.

3) Each party must desire the other’s consent and be prepared to make concessions in order to obtain it.

4) Each party must be accepted as sovereign over matters which concern his very existence as a freely choosing agent. His life, safety and freedom must therefore be treated as inviolable, and to threaten them is to change from dialogue to war.

5) Each party must understand and accept obligations—for example, the obligation to honour an agreement.” (p. 67)

This brief sketch helps us argue that the development of our personhood expresses a proper development of our human nature. For it is certainly plausible to claim that one’s membership in a free community of persons like the one sketched above is necessary to social and rational flourishing. Any social arrangement that contradicts 1-5 is bound to place unacceptable limits on our development (we would expect such limitations in, for example, forms of tyranny, totalitarianism, and fascism). Now clearly I-Thou relations, with their emphasis on subjects, dialogue, freedom, and participation, are consistent with personhood relations. Therefore we can conclude that both forms of relations represent actualized forms of human nature. If this is the case then we are not essentially things that can be objectively experienced, labeled, and manipulated as we might experience, label, and manipulate a chair. Rather, we are essentially social and rational animals that need to grow with others as persons through dialogue. We can then propose the following natural moral law:

NML: We should develop our rational and social potentials by participating in I-Thou/personhood relations.

I think King would agree that segregation violates this natural moral law and is therefore an immoral practice. King’s point that segregation entails false beliefs on the part of the oppressor and oppressed alike (“false sense of superiority” and “false sense of inferiority” respectively) implies that segregation thwarts the development of our essential rational nature since rational dialogue pursues truth rather than falsehood. Moreover, he asked: “Is not segregation an existential expression of man’s tragic separation, his awful estrangement, his terrible sinfulness?” This rhetorical question emphasizes how estranged human beings are from their social potentials. Humans need to grow with each other through participatory dialogue if they are to be fully actualized humans. But segregation turns potential or actual members of a free community into potential or actual monsters who exist more and more outside such a community in an I-It realm marked by oppression, isolation, injustice, falsehood, superficial labels, delusional predictions, violence, and so on.

We can summarize as follows:

  • Segregation “distorts the soul” by preventing the soul from actualizing its natural social and rational potentials—two interrelated aspects that must flourish if we are to be fulfilled and grow as persons individually and collectively.

Now we know racists think they have solidarity with their “superior” community and they think they have the truth. But if the tenets of natural law theory are true, then what they or their society thinks doesn’t determine the good: what matters is what human nature is and whether or not their actions are helping it flourish in themselves and others. And, as we have seen, their actions are not helping human nature flourish. Thus King’s claim that segregation is a form of tragic separation is exactly right: racists think they are actually flourishing when, unbeknownst to them, their efforts to distort the souls of others end up distorting their own souls as well.


Martin Luther King Jr.’s life was exemplary in the ways in which he stood up, through action and argument, for the natural moral law. And his “Letter from a Birmingham Jail”, by giving us intellectual, emotional, and historical resources to do the same, is a priceless natural law theory document. It gives us the resources to piece together powerful arguments against segregation, racism, and all practices that thwart the natural abilities of persons to grow together socially and rationally through dialogue. These arguments, as we have seen, flow from articulating at least two natural moral laws grounded in at least two facts about human nature, namely, its social and rational dimensions. As such, they exist independent of opinions and provide an objective, universal, and intelligible ground for the ethical evaluation of immoral actions and civil laws. Of course, to those who recognize the immorality of certain actions and laws may think have no need of all this theory. Indeed, the call to offer justifications might even seem offensive. But it is important to remember that there are also clever oppressors, often with fancy degrees and institutional affiliations, who will use sophisticated language, ideas, theories, laws, and even philosophy itself to prevent real, long-lasting reform in education, the prison system, the family, the media, the police, politics, and so on. Protests rightly invoke words like ‘rights’, ‘equality’, ‘liberty’, ‘freedom’, and so on; they also employ powerful slogans, art, songs, and chants. But such modes of expressions may not be enough in certain situations which also require articulate speech and convincing arguments. The examples mentioned above – King’s peaceful protests, the prosecution of Nazi war crimes, and Langston’s argument in court – all show how indispensable courageous action is to change. And we can’t overlook the importance of feeling for those who have experienced the evils of racism and other forms of oppression. Love, kindness, consideration, and various forms of solidarity and support must be included. But, as we have seen, there was a time when natural law theory played a role and without it we wouldn’t have established certain reforms such as the Geneva Conventions (see here) and the Civil Rights Act (see here). I think that, as communities, states, and even countries continue the process of legal reform in the wake of recent protests, this theory can play a positive and transformative role as well.

For my post on natural law in the wake of George Floyd’s murder, go here.

2 replies on “91. Martin Luther King, Jr. and Natural Law”

  1. I think MLK’s enemies must have thought he was an “it” and not a “thou” because of his skin color. But since MLK is capable of self-expression, he must have a mind and that is what qualifies a homo sapiens. So, if he can know and speak, he is capable of entering into a dialogue. If he is capable of entering into a dialoge, the other speaker will consider him a human who can speak his mind and reason. So, MLK then, by the very fact that others can see his “dialogue-ness” he is a human in their eyes, and therefore he is a “thou”. MLK wants all persons of color to be “thou’s” not “it’s. There is a way to prove this in arguments, but I have not learned enough in class yet.

  2. Dwight Goodyear on

    Thanks for your helpful comment Sarah. You note that there is a way to prove your point. But you already presented an excellent argument that can be made a bit more formal as follows:

    If someone engages in self-expression through dialogue then they are not an object, an “it”, but a free subject, a “thou”.

    MLK obviously engaged eloquently in self-expression through dialogue.

    Therefore, MLK is a subject: a thou, not an it.

    This has a powerful implication: racists who engage in dialogue with those whom they regard as inferior things are, in the very act of having dialogue with them, demonstrating the falsehood of their racist agenda. No wonder then that so many racists seek to silence those they oppress.

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