The Problem of Evil

The Problem of Evil is widely regarded as the most powerful argument against the existence of a personal God. First formulated by the Greek philosopher Epicurus around 300 BCE, then sharpened by David Hume, J.L. Mackie, and William Rowe, it poses a direct challenge: if God is omnipotent, omniscient, and perfectly good, the existence of suffering should be impossible. We give it an 80/100 soundness score - the highest of any theory on this site - because the evidential version remains compelling and largely unresolved after 2,300 years of debate.

The Core Argument

The argument can be stated in a few simple steps:

1. If God exists, God is omnipotent (all-powerful), omniscient (all-knowing), and omnibenevolent (all-good).
2. An omnipotent God has the power to prevent all evil.
3. An omniscient God knows about every instance of evil.
4. An omnibenevolent God desires to prevent all evil.
5. Evil and suffering exist in enormous quantities.
6. Therefore, God as defined above does not exist.

Each premise is individually difficult for theists to reject. Denying omnipotence, omniscience, or omnibenevolence abandons the traditional concept of God held by Christianity, Islam, and Judaism. Denying that evil exists contradicts direct observation. The only remaining strategy is to argue that God has morally sufficient reasons for permitting evil - a move that shifts the burden to the theist and has driven centuries of theological work known as theodicy.

The Logical Problem of Evil

The strongest form of the argument claims that God and evil are logically incompatible - that no possible world contains both an omnipotent, omnibenevolent God and any instance of evil. J.L. Mackie articulated this version in his 1955 paper “Evil and Omnipotence,” arguing that the three divine attributes and the existence of evil form an inconsistent set.

Most contemporary philosophers consider the logical version addressed, though not definitively refuted. Alvin Plantinga’s Free Will Defense demonstrated that it is logically possible for God to have morally sufficient reasons for permitting evil - specifically, that creating beings with genuine free will necessarily entails the possibility of moral evil. Since Plantinga only needed to show logical possibility, not plausibility, most philosophers accept that the strictly logical version is no longer the strongest formulation.

However, the logical problem is only “solved” in a narrow technical sense. Plantinga showed a way God and evil could coexist, not that this explanation is likely or adequate given the actual scale of suffering in the world.

The Evidential Problem of Evil

The more potent version - and the one responsible for our high soundness score - is the evidential problem of evil. William Rowe advanced this formulation, arguing that even if some evil is logically compatible with God, the sheer amount, distribution, and apparent pointlessness of suffering make God’s existence highly improbable.

Rowe’s key insight is the concept of gratuitous evil - suffering that serves no greater good, builds no character, and leads to no redemption. His famous example: a fawn trapped in a forest fire, suffering for days before dying, unseen by any human. No moral lesson is learned. No soul is built. No greater good results. The suffering is simply wasted.

This version of the argument does not require proving that evil is logically incompatible with God. It only requires showing that the evidence of suffering is far more probable on atheism than on theism - a much lower bar that is much harder for theists to clear.

Natural Evil - The Hardest Cases

Natural evil poses the deepest challenge to theistic belief because it cannot be explained by human free will. Earthquakes, tsunamis, childhood cancers, genetic disorders, pandemics - these arise from the physical structure of the universe itself. The Free Will Defense - widely considered theism’s strongest response to the general problem of evil - simply does not apply here. Tectonic plates do not have free will. The malaria parasite does not choose to kill children. Childhood leukemia is not a consequence of anyone’s moral decision.

Geological Disasters

Earthquakes, volcanic eruptions, tsunamis, and hurricanes arise from the physics of the Earth itself. The 2004 Indian Ocean tsunami killed approximately 230,000 people in a single event, including tens of thousands of children. The 2010 Haiti earthquake killed over 200,000 people, disproportionately affecting the poorest nation in the Western Hemisphere. No human decision caused these events. No moral lesson is proportionate to the suffering they inflict.

Some theists respond with a natural law theodicy - plate tectonics contributes to Earth’s habitability through carbon cycling and maintaining atmospheric composition. This has some force, but an omnipotent God is not bound by engineering trade-offs. He could create a habitable planet without lethal tectonic activity.

Biological and Genetic Suffering

Roughly 400,000 children are diagnosed with cancer worldwide each year. Tay-Sachs disease destroys an infant’s nervous system over two to four years, leading to blindness, seizures, and death - typically by age five. Harlequin ichthyosis causes newborns to be born with thick, cracked skin plates that leave them vulnerable to fatal infection. These conditions arise from mutations, chromosomal errors, and the basic mechanics of cellular biology. They are not punishments, not character-building exercises, and not consequences of free will.

Parasitism

The natural world contains organisms whose entire evolutionary purpose is to exploit and destroy other living things. The guinea worm grows up to a meter inside the human body before slowly boring through the skin, a process lasting weeks of excruciating pain. Naegleria fowleri, the brain-eating amoeba, enters through the nose and destroys brain tissue with a fatality rate exceeding 97%. The ichneumon wasp lays its eggs inside living caterpillars, whose larvae eat the host alive from the inside - a case that troubled Charles Darwin so deeply he wrote that he could not persuade himself a beneficent God would have designedly created it. If God designed this system, he engineered suffering with extraordinary precision and creativity.

Why Free Will Cannot Explain Any of This

The Free Will Defense fails for natural evil on multiple fronts. No agent is responsible - an earthquake is not a moral agent exercising free will, and a virus does not choose to infect a child. Pre-human suffering spans hundreds of millions of years - dinosaurs suffered from bone cancer, and marine creatures were devoured by predators in the Cambrian period over 500 million years ago, long before any free-willed being existed. The fallen angels extension fails - proposing that Satan corrupted nature introduces supernatural agents with no empirical support to explain phenomena that physics and biology already explain completely. The victims cannot benefit - a six-month-old dying from meningitis cannot learn a moral lesson, and a fawn burning alive in a forest fire - William Rowe’s famous example - gains nothing from its agony.

The Scale of Animal Suffering

Complex animal life has existed for approximately 540 million years since the Cambrian explosion. Over 99% of all species that have ever lived are now extinct, each extinction often involving prolonged suffering before the species disappeared. The Permian-Triassic extinction wiped out roughly 96% of marine species approximately 252 million years ago. The K-Pg extinction that ended the dinosaurs 66 million years ago caused widespread ecological collapse and mass death.

Darwin recognized this problem acutely. In an 1856 letter to Joseph Hooker, he wrote: “What a book a devil’s chaplain might write on the clumsy, wasteful, blundering, low, and horribly cruel works of nature.” If an omnipotent God chose evolution as his creative method, he selected the most suffering-saturated process available, sustained it for over half a billion years, and directed it primarily at creatures incapable of moral growth or even understanding why they suffer.

The Problem of Scale and Distribution

The argument gains further force from the distribution of suffering. Suffering does not fall proportionally on the guilty or even randomly across the population. It concentrates on the most vulnerable: children, animals, the poor, and the geographically unlucky. Natural disasters devastate developing nations far more than wealthy ones. Genetic diseases strike without regard to virtue.

This distribution pattern is exactly what we would expect from an indifferent universe governed by physical laws, and exactly what we would not expect from a universe overseen by a just, loving deity. The Problem of Hell extends this concern, asking whether eternal punishment for finite sins is compatible with divine justice.

Major Theistic Responses

The Free Will Defense

Alvin Plantinga’s Free Will Defense argues that God cannot create beings with genuine free will while simultaneously guaranteeing they will never choose evil. A world with free agents who sometimes choose wrongly may be more valuable than a world of moral automatons who always behave perfectly.

This response has real force for moral evil - the evil humans inflict on one another. But it faces serious limitations. It does not explain natural evil at all. Earthquakes and childhood cancers have nothing to do with human free choice. Some theists extend the defense to include fallen angels corrupting nature, but this introduces entities with no empirical support to explain phenomena that physics already explains.

Soul-Making Theodicy

John Hick’s soul-making theodicy proposes that suffering is necessary for moral and spiritual growth. Courage requires danger; compassion requires others’ pain; perseverance requires obstacles. A suffering-free world would produce shallow, untested beings.

The response has intuitive appeal but breaks down at the extremes. A toddler dying from a parasitic infection does not grow spiritually. The millions of species that suffered and went extinct before humans appeared were not building character. And an omnipotent God could presumably create beings with mature moral characters without requiring centuries of anguish as a teaching tool.

Skeptical Theism

Skeptical theism argues that our cognitive limitations prevent us from judging whether any evil is truly gratuitous. God may have reasons for permitting suffering that are simply beyond human comprehension, just as a child cannot understand why a parent allows painful medical treatment.

This is perhaps the most resilient response because it is unfalsifiable - no amount of evidence can refute the claim that God has unknowable reasons. But this same feature is its greatest weakness. If God’s reasons are permanently inaccessible, then the existence of suffering can never count as evidence against God, and the theist’s position becomes immune to any possible observation. Many philosophers consider this an epistemic cost too high to pay, as it undermines the ability to reason about God’s nature from the world we observe.

Greater Good Theodicies

Some theists argue that every instance of evil is necessary for some greater good. A world without suffering would lack the possibility of heroism, self-sacrifice, medical progress, and moral growth. The good of the world, taken as a whole, outweighs the evil.

The problem is that this justification must apply to every instance of suffering, no matter how extreme. Was the Holocaust necessary for some greater good? Were centuries of child mortality before modern medicine justified by eventual medical advances that could have been achieved through revelation? The more extreme the suffering, the harder it becomes to maintain that an omnipotent being had no better option.

The Problem of Evil and Evolution

The discovery of evolution by natural selection deepened the Problem of Evil considerably. As detailed in the natural evil section above, evolution operates through competition, predation, disease, and mass extinction over hundreds of millions of years. Some theistic evolutionists argue that this process produces goods that could not exist otherwise - biodiversity, ecological complexity, and beings capable of genuine emergence and creativity. But omnipotence, by definition, means the ability to achieve any logically possible outcome. If complex life is logically possible without predation, parasitism, and mass extinction, then an omnipotent God could have achieved it painlessly. The Argument from Poor Design reinforces this point: the products of evolution bear the hallmarks of an undirected, iterative process, not purposeful engineering.

Relationship to Other Arguments

The Problem of Evil connects to several other arguments on this site. It is the inverse of the Free Will Defense, which directly attempts to resolve it. It pairs naturally with the Problem of Divine Hiddenness - if God exists and allows such suffering, the least he could do is make his existence and reasons clear. The Problem of Hell extends the moral challenge to the afterlife. And the Argument from Poor Design provides empirical reinforcement by documenting specific design failures in biological organisms.

Pro-God arguments like the Fine-Tuning Argument face a tension here: if the universe’s constants were fine-tuned for life, they were also fine-tuned for a world saturated with suffering. A fine-tuner powerful enough to set cosmological constants could presumably have also tuned them to produce less pain.

Our Scoring

Soundness: 80/100. This is the highest soundness score of any theory on the site. The evidential version, championed by William Rowe, remains compelling and largely unresolved. The premises are empirically grounded - evil exists, its scale is staggering, and much of it appears gratuitous. Skeptical theism provides a logical escape route but at the cost of making God’s nature unknowable. The Free Will Defense handles moral evil but leaves natural evil unexplained. No theodicy has successfully accounted for the full scope and distribution of suffering in the world. The score is not 100 because the argument targets a specific definition of God (omnipotent, omniscient, omnibenevolent) rather than all possible conceptions, and skeptical theism remains a logically available (if costly) response.

Personal God: 10/100. This is a devastatingly low score. The Personal God - omnipotent, omniscient, omnibenevolent, and actively intervening in human affairs - is the conception most directly contradicted by the existence of suffering. Such a God could prevent evil, knows about all evil, wants to prevent evil, and supposedly intervenes in the world. The gap between this definition and the observed reality of suffering is enormous. The few points above zero reflect the bare logical possibility that some unknown justification exists.

Creator/Designer: 35/100. A creator who designed the universe is less affected because this definition does not require omnibenevolence. A morally neutral or indifferent creator could have built a universe that produces suffering without moral contradiction. However, the score remains low because the sheer gratuitousness of much suffering - parasites that eat children’s eyes from the inside, for instance - sits uncomfortably even with a morally neutral designer. A competent designer with any moral consideration would likely have done better.

Higher Power: 40/100. An impersonal supernatural force or consciousness behind reality is the least affected by the Problem of Evil. Such an entity would not be expected to intervene, to care about individual suffering, or to have moral obligations toward creatures. The score is somewhat higher than the Creator because an impersonal force is not “designing” suffering but merely underpinning a reality that happens to contain it. The score is still below 50 because even an impersonal higher power seems difficult to reconcile with a universe where suffering is so pervasive and seemingly purposeless.