The existence of evil in a world created by an all-good, all-powerful God has puzzled and challenged thinkers for centuries. Why do suffering, moral failure, and natural disasters occur if God is both loving and omnipotent? These questions, often called “the problem of evil,” require careful thought and explanation. Drawing on the insights of St. Thomas Aquinas and St. Augustine, we can explore the nature of evil, its place in creation, and its relationship to God’s goodness and power. By examining Augustine’s foundational idea of evil as a privation of good (Privatio Boni) and Aquinas’ integration of this concept into a broader metaphysical framework, we can reconcile these apparent contradictions. Together, their reasoning helps us see how evil fits within a divine purpose and points to the ultimate hope found in God’s plan.
Evil as Privation: What Evil Is and Is Not
To understand the problem of evil, we must first ask: What is evil? Evil is not a thing in itself. It is not a substance or entity that God created. Instead, as St. Augustine explained, evil is a privation of good (Privatio Boni)—a lack of something that ought to be there. While often seen as the opposite of good, evil is not its equal or counterpart in the sense of having a positive nature. It is opposed to good only as a deficiency or corruption of what should exist.
From the beginning, God created the world and declared it “good” (Genesis 1:10). Humanity, as the pinnacle of creation, was declared “very good” (Genesis 1:31), reflecting the unique capacity for rationality, relationship, and participation in divine life. Evil, therefore, is not something God willed or created but arises as a deficiency or distortion within the goodness of creation.
Augustine captures this idea succinctly in City of God: “Evil has no positive nature; but the loss of good has received the name ‘evil.’” He likens evil to darkness, explaining in his Confessions: “What else is this than the absence of light?” Just as darkness is the absence of light, and blindness the absence of sight, evil is the absence of good. It is not a substance or force but a corruption of what ought to be.
Aquinas builds on this foundation, stating in the Summa Theologiae: “It must be that by the name of evil is signified the absence of good. And this is what is meant by saying that ‘evil is neither a being nor a good.’” For Aquinas, all being is inherently good; therefore, evil implies a corresponding absence of being. This metaphysical framework allows him to further clarify: “Evil considered even as a privation is said to corrupt good, forasmuch as it is itself a corruption or privation of good.” In other words, evil is parasitic on good, existing only where good exists to be corrupted or diminished.
This distinction is crucial. Evil, like a shadow, depends on light for its existence and cannot exist independently. As Augustine notes, “Evil would have no foothold in creation unless man was capable of being corrupted to begin with.” When creation falls short of its intended purpose or order, it becomes disordered and corrupt. This raises a critical question: Why would a good God allow these deficiencies? To answer this, we must examine the different kinds of evil.
Evil Suffered and Evil Done
Aquinas distinguishes between two kinds of evil: malum poenae (evil suffered) and malum culpae (evil done).
Evil Suffered (Natural Evil)
This is the suffering that comes from the natural world: earthquakes, diseases, and accidents. It is what happens when the laws of nature operate without malice but with indifference. A lion kills its prey to survive. A tree falls in a storm and destroys a house. These are not acts of choice but the workings of a world governed by consistent natural laws. Yet we might ask, Why did God create a world where natural disasters and diseases exist at all? Could He not have created a world without suffering?
The answer lies in the necessity of order. A world where fire burns, water flows, and gravity pulls must also be a world where those laws occasionally cause harm. A fire warms the cold, but it also burns the careless. Gravity keeps us grounded, but it also causes falls. A world without these consistent laws would be incoherent and uninhabitable. We might think we desire a world without such risks, but would we truly want it? A child learning to walk must risk falling. A life without storms would also be a life without rain to nourish the earth. The same laws that permit suffering also allow for beauty, growth, and freedom.
This balance extends to the micro-level of life itself. Consider the human body, a marvel of complexity and order. It is governed by cellular processes that sustain life—cell division allows for growth and healing, the immune system defends against disease, and DNA mutations drive adaptation and survival over generations. Yet these same processes can sometimes go awry. A cell may mutate in a way that leads to cancer, causing suffering and death. Why would God allow such mutations?
The same principle applies: the laws that allow for life and its flourishing also allow for its potential disruption. Mutations are a necessary part of biological systems, enabling evolution, adaptation, and diversity in life forms. Without them, life as we know it could not exist. The price of these possibilities, however, is the risk that some mutations may lead to harm. Just as gravity can hold a planet in orbit but also cause a falling branch to injure someone, the same biological mechanisms that sustain life can sometimes cause suffering.
This interconnectedness reflects the broader reality of a consistent and ordered creation. A world without such risks would not only be incoherent but devoid of the richness, resilience, and creativity that life entails. The challenge is not to reject these laws but to recognize that they are part of the greater good of a creation that is fundamentally ordered and meaningful.
Evil Done (Moral Evil)
This is the evil that arises from human choices. A thief steals, a tyrant oppresses, and a murderer takes life. Here, the problem is not with nature but with the human will. But why would God allow humans to do evil? Could He not have created a world where humans always chose good? The answer lies in the nature of freedom. To be truly free, humans must have the capacity to choose wrongly. A choice that cannot go wrong is not a choice at all.
Imagine a man who programs a robot to say, “I love you.” Would the robot’s words mean anything to him? Of course not. Love, like all virtues, requires freedom. Without the possibility of evil, there can be no genuine virtue, no courage, no love, no growth. This freedom is a dangerous gift. It has been used to commit atrocities and cause immense suffering. But without it, we would not be human. We would be automatons, incapable of moral responsibility or true goodness.
Why Not Begin in Perfection?
One might counter that Heaven is a place where perfection has been attained by men through purgation and grace. If this is possible in the eternal realm, why not create humanity in such a state from the beginning? Would it not be possible for humans to be created with a will oriented towards perfection, achieving harmony without the risk of sin?
The Necessity of the Journey
Aquinas and Augustine both acknowledge that Heaven represents the fulfillment of human nature, where free will persists but is perfected by its alignment with God. However, they also emphasize the significance of the journey toward this perfection. For Augustine, the fall and redemption reveal the depths of God’s love and mercy. Without the possibility of failure, the glory of salvation and grace would not be fully manifest. Aquinas adds that the temporal world is where humans exercise their free will in a way that shapes their eternal destiny. In Heaven, the will is not “automatized” but freely perfected, having been purged of all disorder through the trials and redemptive grace of earthly life.
Thus, the need for a temporal journey lies in the process of becoming. To begin in Heaven, perfectly aligned with God’s will, would bypass the meaningfulness of choosing that alignment. The choice to love, trust, and follow God in the midst of struggle reveals a depth of relationship and virtue that cannot arise from instant perfection. In this sense, God’s design of the earthly life as a precursor to Heaven reflects His desire for humans to share in the process of their sanctification rather than having it imposed upon them from the outset.
Evil Done: A Greater Purpose
This journey, fraught with the possibility of sin and moral evil, is not a flaw in God’s creation but part of its beauty and purpose. As Augustine observes, “God judged it better to bring good out of evil than to suffer no evil to exist.” The freedom to choose—even wrongly—is integral to this greater good, allowing the full spectrum of God’s justice, mercy, and love to be revealed.
Why Doesn’t God Stop Evil?
Even if we accept that freedom is necessary, we might still ask: Why doesn’t God intervene to stop the worst evils? Could He not prevent a child’s death or stop a tyrant before he acts? This question strikes at the heart of our understanding of divine providence and human freedom.
To answer, imagine a teacher in a classroom. If the teacher intervenes every time a student makes a mistake, the students will never learn. They will become dependent on the teacher, incapable of reasoning or growing on their own. Similarly, if God were to prevent every act of evil, human freedom would be meaningless. We would cease to be moral agents and instead become puppets manipulated by divine strings. Our choices would lose their significance, and with them, the opportunity to grow in virtue, love, and wisdom.
This does not mean God is indifferent to evil or suffering. On the contrary, He entered into human suffering through Jesus Christ. In the Cross, we see that God is not distant from our pain but intimately involved in it. Christ’s suffering and death are the ultimate testament to God’s solidarity with humanity. He does not merely watch us suffer; He suffers with us and for us, offering redemption and hope in the face of evil.
Furthermore, God’s restraint does not imply passivity. Through His providence, He continually works to bring good out of even the gravest evils. As Joseph famously said to his brothers, who sold him into slavery: “You meant evil against me, but God meant it for good” (Genesis 50:20). This principle applies universally: while God permits evil as a consequence of human freedom, He also ensures that it does not have the final word. The resurrection of Christ is the ultimate proof that God can transform even the greatest evil into the greatest good.
God’s Creation and Moral Accountability
To understand this, imagine trying to blame a mathematician for not making 2+2=5. The problem isn’t that the mathematician lacks the power to do so; it’s that the very concept is incoherent. Similarly, Aquinas would say, trying to morally evaluate God’s creative choices is fundamentally confused. God isn’t a moral agent like us, bound by obligations and duties. He is, rather, the source of all being and goodness itself.
Aquinas would reject the notion of God being bound by external moral standards, as it would imply the existence of a higher principle to which He is subject. This contradicts the nature of God as ipsum esse subsistens—the very act of being itself. God is not a being among beings, one entity within creation, but the source and ground of all existence. As Aquinas explains, “Being itself is the most formal of all things and is the actuality of all acts” (Summa Theologiae, I, 4, 1).
Thus, any notion of God being measured against an external standard misunderstands His nature. Rather, God’s goodness is not derived from conformity to something outside Himself but flows from His very essence as the source of all that is good. His creative act, then, is not judged by external criteria but is intrinsically aligned with His nature as the fullness of being and goodness.
This reasoning echoes Augustine’s earlier assertion that evil has no positive nature—it is not something God created, but a corruption or deficiency in what He did create. For Aquinas, as for Augustine, this privative view of evil is critical. In the Summa Theologiae, Aquinas affirms, “It must be that by the name of evil is signified the absence of good. And this is what is meant by saying that ‘evil is neither a being nor a good.’” Evil, whether suffered or done, can only exist because good first exists. It is parasitic on goodness and cannot exist independently.
Aquinas takes this idea further by integrating it into his broader metaphysics. For Aquinas, the good is identical with being itself. Everything that exists is good insofar as it exists. A “bad” thing, like a faulty clock or a corrupt politician, still has some goodness because it exists as a clock or a human being. However, its deficiency—its failure to function as it ought—represents a falling short of its intended purpose. This reflects Augustine’s teaching that evil is a privation of the good that should be there. For instance, a tree rotting from disease still owes its existence, beauty, and usefulness as wood to God’s creative act, even though the disease has corrupted its perfection. The defect, however, is not caused by God but arises from the limitations inherent in creation.
Both thinkers agree that God, as the source of all being and goodness, cannot be the direct cause of evil. As Aquinas writes, “God is not the cause of evil that consists in the loss of good, but He is the cause of the good that is diminished by the defect” (Summa Theologiae, I, 49, 1). In other words, God causes the good in creation, even when that good is marred by the effects of sin or suffering.
This theological framework provides a consistent way to understand how evil fits into God’s creation. God is not the author of evil, but He allows it as a possibility within the good, ordered, and free world He has created. In respecting human freedom, God’s creative act also allows for the possibility of moral failure. Yet this same freedom reflects His nature as the source of good, enabling humanity to participate in His plan through acts of love, justice, and virtue. This understanding invites us to trust that even the defects we encounter in creation are part of a broader providential plan, where God continually works to bring good out of the imperfections of the world.
Evil and the Eternal Perspective
The problem of evil is deeply tied to our limited perspective. We see only the immediate pain, the tragic loss, and the apparent senselessness of suffering. But God sees the whole picture, the eternal purpose behind every moment. Imagine a tapestry viewed from the back. The threads appear tangled, chaotic, and devoid of meaning. Yet, when viewed from the front, those same threads form a beautiful and intricate design. Our lives, too, are part of a tapestry that only God sees in its fullness. What seems like senseless suffering now may, in eternity, reveal itself as part of a greater good.
This is not to dismiss suffering or to suggest that we should celebrate it. The weight of pain is real, and trusting in an unseen purpose can feel nearly impossible in the midst of it. Yet faith calls us to believe that evil does not have the final word. In Revelation, we are promised that God will “wipe every tear from their eyes” and that “death shall be no more” (Revelation 21:4). This is the Christian hope: that all things will be made new, and every pain will find its redemption.
Through this lens, we begin to see that God’s providence extends even to suffering. What appears meaningless now is woven into the eternal story of creation and redemption. While we may not understand how in this life, the promise of eternity assures us that every thread, even those that seem dark and frayed, has its place in the ultimate good.
The Practical Response to Evil
What, then, is our response to evil? First, we must confront it with courage and compassion. When we see suffering, we are called not to despair but to act—to comfort the grieving, feed the hungry, and fight injustice. In doing so, we imitate Christ, who healed the sick, comforted the brokenhearted, and ultimately gave Himself for the redemption of humanity. Each act of mercy, no matter how small, is a participation in His redemptive work and a sign of hope in a broken world.
Second, we must trust in God’s goodness, even when we do not understand. This trust is not blind faith but a recognition that God’s wisdom surpasses our own. As the Apostle Paul writes, “For now we see through a glass, darkly; but then face to face” (1 Corinthians 13:12). Trusting God does not mean passivity; it means engaging with life’s challenges while believing that God’s providence is at work in ways we cannot yet see.
Finally, we must understand that suffering is not meaningless; it reveals and refines the human soul. As Augustine so eloquently puts it:
For, in the same fire, gold gleams and straw smokes; under the same flail the stalk is crushed and the grain threshed; the lees are not mistaken for oil because they have issued from the same press. So, too, the tide of trouble will test, purify, and improve the good, but beat, crush, and wash away the wicked. So it is that, under the weight of the same affliction, the wicked deny and blaspheme God, and the good pray to Him and praise Him. The difference is not in what people suffer but in the way they suffer. The same shaking that makes fetid water stink makes perfume issue a more pleasant odour.
Here, Augustine captures the essence of what suffering does: it reveals the character of those who endure it. The same circumstances may lead one person to despair and another to faith. The good are tested and strengthened, while the wicked are further separated from God. Suffering, then, is not just an obstacle but a crucible, refining the virtues of those who respond with love, patience, and trust.
This is not to romanticize suffering or to suggest that it is desirable in itself. Rather, it is to acknowledge that suffering is part of the human condition and that, in God’s providence, it can be transformed into a means of growth, purification, and grace. Our task is not to flee from suffering but to face it with faith, knowing that God works through it to bring about His purposes. In doing so, we unite our struggles with Christ’s suffering, trusting that all things work together for good in the eternal tapestry of His plan.
The Choice Before Us
The problem of evil is a mystery, but it is not without meaning. God’s creation, though marred by suffering and sin, is still “good.” It is a world designed for freedom, growth, and redemption. Evil exists as a privation of the good, not as something God created but as something He allows for the sake of a greater purpose. This purpose is rooted in His desire for us to freely choose goodness and to grow in virtue through our struggles.
Our task is not to despair but to choose how we will respond. Will we allow suffering to harden our hearts or open them to love, trust, and hope? Will we align ourselves with God’s purpose, trusting in His goodness even when we cannot fully understand it? The Cross of Christ assures us that even the greatest evil can be transformed into the greatest good. In the Cross, God entered into our suffering, taking on its weight and redeeming it through His love. It is the ultimate sign that evil is real, but it is not final.
As we face the trials of life, we are called to participate in God’s redemptive work—to comfort the grieving, fight injustice, and bring light into the darkness. This is not merely an act of duty but a reflection of God’s own goodness working through us. In doing so, we join Him in His plan to bring all things to fulfillment.
In this, we find not only an answer to the problem of evil but also the hope that sustains us. For we are assured that one day, “every tear will be wiped away,” and all things will be made new (Revelation 21:4). Until that day, we live in the promise of the Cross, knowing that the story of creation ends not in defeat but in victory.
