Augustine’s hamartiology cannot be understood without examining the interaction between his perception of God and Neoplatonic cosmology, in which God is understood as the one supreme, transcendent being. Despite Augustine’s active appropriation of Neoplatonic cosmology as the framework for his hamartiology, the interaction marks a philosophical as well as theological break with Manichaeism as well as Neoplatonism itself in the process of Augustine’s search for the monotheistic God. Augustine was convinced that the one supreme being of Neoplatonism was very close to the God of Christianity; accordingly, his understanding of God became the premise for his doctrine of evil and sin. In this way, in his early thought the doctrine of evil and sin functions as a subcategory of his doctrine of God as it gives direction to all of his theological concerns. In his later hamartiology, however, he introduced biblical exegesis into his hamartiological system and formulated the doctrine of original sin that has since governed Western hamartiology as well as anthropology.

Of the many theological doctrines of Augustine, the doctrine of original sin has been one of the most debated and ongoing controversies in Western theology, mainly due to the theological fusion between his hierarchical cosmology and his exegesis of biblical accounts, in which he placed his own Pauline interpretation at the center of the discussion. Augustine basically attempts to justify his doctrine of original sin within his philosophical system in connection with Scripture; however, it is undeniable that his logic and descriptions are strongly bounded by his theological presuppositions, such as his concept of God, his cosmology, and the doctrine of predestination, all of which lead him to an unbalanced view of hamartiology. More importantly, even though Augustine’s doctrine of original sin lays a solid foundation for the universality of sin and the sinful solidarity of the human race, it does not fully encompass the doctrine of Christ nor the doctrine of the new created human being in it, focusing more on the qualitative difference between the supreme God and fallen humanity. Accordingly, there is a considerable lack of correspondence between Augustinian doctrine of original sin and the sinful experience of people as well as the testimonies of Scripture, especially in the relationships between the universality of sin and human responsibility, sin as “non-being” and the presence of radical evil in the world, and the sinful experiences of males and females.

This chapter begins with an examination of Augustine’s philosophical discussion of theodicy in which his notion of God along with his Christianized Neoplatonic cosmology becomes the foundation of his hamartiology. Second, it describes Augustine’s early focus on fallen humanity’s inward turn of the self as the central Augustinian account of hamartiology. In the process, the chapter investigates the function of his Christianized Neoplatonic system in his search for human sinfulness. Then, it examines Augustine’s later hamartiological shift, which combines his biblical exegesis with his Christianized Neoplatonic cosmology. It discusses the theological meaning and significance of the doctrine of original sin as well as the controversies that are the basis of later chapters dealing with the doctrines of Luther and Bonhoeffer. Finally, it concludes by mentioning the theological implications that are discussed in later chapters.

The problem of evil was one of the key issues with which Augustine struggled before his conversion to Christianity.³ Augustine’s questions related to the problem of evil and the essence of God remained with him on his spiritual journey through the most influential religious and philosophical systems of his time, which were primarily Manichaeism, Neoplatonism, and finally Christianity. When he was a teenager, Augustine had been deeply engaged in the Manichaean religion.⁴ Manichees were deeply concerned with the relation between God and the existence of Evil. According to Manichaeism, there are two opposite primordial beings—one good God and one Evil, light and darkness—and these two opposite forces are continuously wrestling in the universe. Manichees understood the world as a battlefield between two opposite powers. The advantage of this dualistic understanding of God and Evil is the fact that its explanation of the compatibility between the existence of God and the reality of evil in the world caused by the existence of Evil appears more reasonable and simpler than the monotheistic understanding of God.

Thus, it is not surprising that the Manichaean understanding of the universe attracted Augustine, who had been searching for an answer to this dilemma since his youth.⁵ This issue had been not only one of the main obstacles for Augustine before his conversion to Christianity but was also a continuous philosophical as well as theological concern in the process of his theological development, especially in his hamartiology. After spending more than nine years as a “hearer” of Manichaeism, however, Augustine found himself unsatisfied with the metaphysics of Manichaeism, which held a materialistic and corporeal conception of God as non-omnipotent. Augustine’s dissatisfaction with Manichaeism’s concept of evil was primarily due to its understanding of the characteristics of God.⁶ He found that a materialistic and corporeal God is contradictory to the presence of evil in the world because if God is filled with the creation physically and materialistically, then there is no place without God, and therefore there is no place for evil.⁷ Augustine’s concept of God at this point combined the idea of a materialistic and infinite God with that of a monotheistic God. Augustine could not accept the dualistic Manichaean understanding of God and Evil because it made God non-omnipotent and non-omnibenevolent.

Then, Augustine turned to ideas of Neoplatonism. In Confessions, he vividly describes his search for an answer to the question of the problem of evil and God. He points out that his reading of “certain books of Platonists” made him understand God spiritually for the first time.⁸ He began to understand the Christian notion of God and God’s creation through a Neoplatonic lens, especially through Plotinus’ Enneads.⁹ He found several important clues to solving the dilemma from his reading of Plotinus. Most importantly, Augustine discovered a hierarchical and ontological cosmology in which one Supreme Being, who is God, is placed at the top. As Lewis Ayres comments, Augustine became convinced that the hierarchical order in creation is “a vehicle of God’s self-manifestation.”¹⁰ Augustine believed that if one traces up to the top of the hierarchical order of being by the power of reason, then one can discover God, who is eternal and unchangeable.¹¹ Augustine clearly defines God as quo nullus est superior, “to whom none is superior,” in the system of the hierarchy of being in which evil can be understood as “privation of good” and as “non-being” rather than an ontological being or substance.¹² Augustine perceived that here he had finally found the explanation for the problem of evil against the idea of Manichaeism.

Certainly, Augustine combines his Christianized, Neoplatonic, hierarchical cosmology with the Christian concept of God. Against Manichaean dualism, Augustine attempts to refine his doctrine of evil. In the process, Augustine’s active appropriation of Plotinus is evident.¹³ He reforms Plotinus’ cosmology into the Christian way, applying his hermeneutical method that converts pagan intellectual assets to Christian use.¹⁴ As Gerald Bonner properly points out, although Augustine borrows Neoplatonic ideas for his cosmological system, he attempts to reformulate them in a Christian way.¹⁵ Accordingly, Augustine is very careful not to reduce the sovereignty or attributes of God in his description, especially in his appropriation of Neoplatonism. Augustine’s revision of Plotinus’ cosmology functions in two ways. First, he draws on the order of creation as a means to refute the dualism of Manichaeism. Second, he tries to eliminate the Neoplatonic dualism between matter and soul in which evil is included in the materialistic universe as a necessary result of its emanation from the Supreme Being. This is because the notion of pre-existing matter of Neoplatonism per se inevitably contains the evil nature. Plotinus explains that although the cosmos comes from the Supreme Being by emanation, it is made out of matter that already existed before creation, and it contains evil because it has not yet been brought to order.¹⁶ In other words, the cosmos has two different origins: God and matter. Plotinus understands the cosmos as a mixture of good and evil, soul and matter.¹⁷ The logic of Plotinus does not perfectly eliminate the possibility of dualism because he does not deny possibility of corruption of matter, which Augustine directly relates with evil. Bonner clearly notes this point, writing that “Plotinus, while firmly relegating Evil to the realm of Non-Being, never arrives at the Augustinian position of Evil as simply a privation of Good.”¹⁸

In Neoplatonism, creation has two origins: the one Supreme Being and matter. Thus, this can be considered a kind of dualism in which not only the source of human corruptibility but also the non-omnipotence of God is implied. For this reason, Augustine reformulates Plotinus’ system in a Christian way. The conclusion is evident. If God is omnipotent and omnibenevolent and the good God created the universe, God’s creation is also “good”; therefore, there should be no place for evil in God’s created world.¹⁹ He rejects not only Plotinus’ concept of emanation but also the concept of the pre-existence of matter that prevailed in ancient Greek philosophy.²⁰ His final choice has to do with denying the existence of evil within his Christianized Neoplatonic cosmology by placing evil at the bottom of the order of creation as non-being or simply privation of good, which undergirds the attributes of God, especially omnipotence and omnibenevolence, in the trilemma.²¹ For Augustine, this Christianized Neoplatonic cosmology is the starting point for perceiving the relation between God and evil as well as between God and humanity.²²

In short, Augustine borrows the ontological frame of Plotinus to uphold God’s benevolence and omnipotence and to properly situate evil. Accordingly, evil can be treated as non-being but not as substance. Augustine explicitly finds the Neoplatonic cosmology the most proper lens for approaching the problem of evil as well as the notion of God. However, the difficulty of Neoplatonism in regard to the problem of evil is that Neoplatonism does not perfectly eliminate the risk of dualism between matter and God because of its attribution of evil in matter. To discard the problem of matter, Augustine turns to the doctrine of creatio ex nihilo (creation out of nothing) that he received from the Christian tradition.

Furthermore, Augustine notices that when one turns to humanity, the problem of evil becomes more complicated because humanity is composed of two components: soul and body. Apparently, these two contradictory aspects have been in humanity since the creation. For his refutation of the dualism of the Neoplatonists, Augustine once again follows his philosophical principle applied in his previous refutation of Manichaeism in which his concept of God functions as the ultimate proposition for his theological consideration. He argues in The Nature of the Good: