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 grounds this remarkable claim in a philosophical theory known as natural law theory. He writes:


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 perhaps 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.

There are four basic ideas behind natural law theory that remain constant despite the diverse aspects of this rich tradition:

(1) The theory maintains there are moral laws to be found in nature just like there are scientific laws to be found in nature. Recall that scientific laws are only descriptive: they are generalizations that claim to describe how the physical world does in fact work on a very fundamental and general level. For example, Isaac Newton’s Third Law of Motion (when one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body) is just a description of how motion occurs on a general level. There is no prescription regarding what we should or should not do. But a natural moral law is prescriptive or normative insofar as it will tell us how we should act. If we can know natural moral laws then we can have moral guidance in our efforts to judge how to realize natural goodness. Indeed, these laws would hold for all insofar as they, like scientific laws, would be universal, objective, and intelligible or capable of being understood.

(2) We can know a natural law using our reason—we don’t need revelation from God or any mysterious capacities or talents.

(3) We can know what natural laws exist by rationally analyzing human nature, what our very essence is, and formulating moral prescriptions based on this nature.

(4) 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 natural potential. 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. This is impressive since many who advocate human rights have no arguments for why we should have rights. To be sure, people argue about how many rights we should have, which ones we should have, whether they can be taken away, and so on. But what could we say to someone who challenged the very notion of rights in the first place? There is no argument given in support of the rights in the UN 1948 Declaration of Human Rights.  And our Declaration of Independence states that it is self-evident, in other words, no reason is needed, that everyone has the right to life, liberty and the pursuit of happiness. But if we are interested in justifying rights—and I think we should be given the evidence of rights violations and the widespread disagreement about them—then natural law allows us to provide a justification for them.

Summary: Ethical theories attempt to do at least two things: (1) define terms like good, bad, right, and wrong on a general and fundamental level and (2) give a guiding principle that helps us make and defend moral judgments. According to natural law theory, the unfolding of something in accordance with its essential nature is good; right action will be action that facilitates this natural unfolding; and action can be both guided and judged by articulating objective, intelligible, and universal natural moral laws found in human nature. These moral laws can then serve as a fundamental foundation for natural rights that help insure the flourishing of our essential nature.

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. One of the best examples of this use of natural law can be seen in the following passages from Martin Luther King, Jr.’s “Letter from a Birmingham Jail” (April 16, 1963):


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).”

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 contradictions 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 grow with others as persons through dialogue. For the natural law theorist, this means

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 of isolation, falsehood, superficial labels, and delusional predictions.

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: the racist thinks he is actually flourishing when, unbeknownst to him, his soul is being distorted.


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.


  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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