Abstract

The concept of sin is commonly regarded as a defining feature of Christian anthropology, structuring both the diagnosis of the human condition and the necessity of salvation. Yet this apparent centrality conceals a deeper philosophical problem. The doctrine of original sin, often treated as foundational within Christian thought, is not articulated in the teachings attributed to Jesus. This raises the question of whether sin, especially in its developed form, is an essential component of Christianity or the result of a specific historical and interpretive development within the tradition. This essay proceeds from the observation that the phenomenon to which sin responds, namely inner division, the experience of failing to act in accordance with one’s own understanding, does not determine its own meaning. It can be interpreted in multiple ways, none of which are given in advance by the experience itself. The concept of sin must therefore be understood not simply as a description, but as an interpretation that organizes and stabilizes this ambiguity. The analysis begins with the teachings attributed to Jesus in the Gospel of Matthew and the Gospel of Luke, where sin appears as a relational and reversible reality rather than an inherited or ontological condition. The emphasis falls on repentance, forgiveness, and restoration, suggesting that human failure, while real, does not define the essence of the human being. This relative openness indicates that the later doctrine of original sin is not directly grounded in the earliest layer of the tradition. A decisive transformation occurs in the writings of Paul the Apostle, where inner division is reinterpreted as evidence of a structural condition. Sin becomes not merely an act but a power that operates within the individual, introducing a form of necessity into human existence. This shift represents not only a theological development but a reconfiguration of how human experience is understood. In Augustine of Hippo, this trajectory is stabilized into the doctrine of original sin, according to which human nature is marked by an inherited impairment of the will. At this point, the interpretive openness of earlier stages is significantly reduced. Inner division is no longer a phenomenon open to multiple readings, but the expression of a universal and ontological condition. This development also carries implications for the structure of mediation and authority, insofar as the human capacity for self-transformation is fundamentally limited. The trajectory reaches an existential culmination in Søren Kierkegaard, where sin is internalized as despair, a condition embedded in the structure of self-relation. Here, the interpretation of sin becomes fully inward and inescapable, transforming a historical doctrine into a lived existential reality. In contrast, the Gospel of Thomas presents an alternative anthropology in which the fundamental problem is ignorance rather than sin. This suggests that the dominance of sin as the primary interpretive category is not inevitable, but historically contingent. The essay argues that Christianity does not simply reveal sin as an essential truth about human existence. Rather, it progressively transforms the experience of inner division into the concept of sin, culminating in the doctrine of original sin as a historically developed framework that both clarifies and constrains the understanding of the human condition. The existential intensification of this framework raises the further question of whether the demand for inward self-transparency may itself contribute to the persistence of despair, thereby exposing the limits of sin as a comprehensive interpretive category