The Concept of Justice in Platonic Thought and Its Development in the Philosophy of Saint Augustine

Abstract

This study traces the intellectual evolution of the concept of justice from its foundations in Platonic political philosophy to its reformulation in the Christian theology of Saint Augustine. In Plato’s thought, justice is a rational virtue grounded in cosmic order, attainable through philosophical knowledge and essential for harmony within both the soul and the ideal state. Augustine, however, redefines justice within a theological framework centered on divine grace and salvation. For him, true justice is a gift from God and is realized not in any earthly political order but in the spiritual community of the Heavenly City. This transformation constitutes the core research problem. The study investigates how justice shifted from a human-centered, political and ethical ideal into a divinely ordained, eschatological promise. Examining this transition sheds light on broader changes in conceptions of human nature, political authority, and the possibility of moral perfection between the classical and early Christian periods. The significance of this research lies in its analysis of a pivotal moment in Western intellectual history. By clarifying this conceptual shift, the study reveals the philosophical origins of the enduring distinction between temporal and spiritual authority and provides historical context for modern debates concerning religion’s role in public life and the limitations of secular political projects aiming at perfect justice. Methodologically, the research adopts a critical analytical and comparative approach based on close textual analysis of Plato’s Republic and Augustine’s City of God. Through systematic comparison, it reconstructs the logical and historical development of the concept of justice, highlighting Augustine’s critical yet creative engagement with the Platonic tradition.