Martin Luther King Jr. is the greatest American philosopher and gave his life seeking justice for all Americans. While imprisoned in 1963, King highlighted the importance of justice and advocates for a unified society in his “Letter from a Birmingham Jail.” This letter addressed Alabama clergymen’s grievances with the civil rights movement being unwise and untimely. King’s response highlights the importance of civil rights to achieve justice.

But what is King’s justice? As a theologian, King had familiarity with Aristotle and Plato, whose work shaped King’s ideas about a just society. In Plato’s masterpiece “Republic,” Socrates defines individual justice as working at what one is best suited, to do one’s business and not be a busybody.

But who holds the state accountable if it itself is unjust? In Book V of “Nicomachean Ethics,” Aristotle directly addressed this issue. Aristotle broke political justice into two parts: human laws that vary by location, and natural law that is applicable to all. Therefore, should human and natural law conflict, the ethical course of action is to follow natural law.

In “Letter from a Birmingham Jail,” King established his ethical framework for civil disobedience. He concluded that America is unjust because it is divided among two separate cities: one white and one black. Therefore, black Americans do not have an ethical obligation to follow state laws that unjustly favor one race.

This concept builds upon Plato and American sociologist W. E. B. Du Bois concept of separate identities within a unified society. In “Republic,” Socrates remarks that within every city, there are two other cities: one rich and one poor, and a just society is unified. In his 1903 book “Souls of Black Folk,” Du Bois applies this concept to black Americans, calling it double consciousness. Du Bois remarked that black Americans look at themselves from two lenses: how they see themselves and how society sees them. Therefore, King synthesized both Du Bois and Plato’s ideas and worked toward a unified country.

King’s greatness rests in his ability to apply principles from natural law to the Constitution — a place of liberty, justice for all and internal character determining value. His conviction toward shining the bright light of truth and justice into the darkness of American society cost him his life.

King gave his dream for a unified America. Let’s make it happen.