The Problem of Evil

The Problem of Evil asks: if God is all-powerful, all-knowing, and all-good, why does suffering exist? It is widely regarded as the strongest argument against a personal God. First posed by the Greek philosopher Epicurus around 300 BCE, then sharpened by David Hume, J.L. Mackie, and William Rowe, it remains the highest-scoring theory on this site at 80/100 soundness because no theodicy (an attempt to justify God’s allowing evil) has fully answered it 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 hard to reject. Denying any of the three “omni” properties abandons the traditional God of Christianity, Islam, and Judaism. Denying that evil exists contradicts direct observation. The only remaining move is to argue that God has good reasons for allowing 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 all-good, all-powerful God and any evil at all. J.L. Mackie made this case in his 1955 paper “Evil and Omnipotence,” arguing the three divine attributes and the existence of evil form an inconsistent set.

Most philosophers today consider the logical version addressed, though not fully refuted. Alvin Plantinga’s Free Will Defense showed it is logically possible for God to have good reasons for allowing evil - namely, that creating beings with real free will means accepting the possibility they will choose evil. Since Plantinga only had to show logical possibility, not plausibility, the logical version is no longer the strongest form of the argument.

But 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 given the actual scale of suffering.

The Evidential Problem of Evil

The stronger version - and the reason for our high soundness score - is the evidential problem of evil. William Rowe argued 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 idea is 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 lesson is learned. No soul is built. No greater good results. The suffering is simply wasted.

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

Natural Evil - The Hardest Cases

Natural evil is the deepest challenge to theism because it cannot be blamed on human free will. Earthquakes, tsunamis, childhood cancers, genetic disorders, pandemics - these come from the physical structure of the universe itself. The Free Will Defense, theism’s strongest response to the general problem, 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 the result of anyone’s moral decision.

Geological Disasters

Earthquakes, volcanic eruptions, tsunamis, and hurricanes come from the physics of Earth itself. The 2004 Indian Ocean tsunami killed about 230,000 people in a single event, including tens of thousands of children. The 2010 Haiti earthquake killed over 200,000 people, hitting the poorest nation in the Western Hemisphere hardest. No human decision caused these events. No lesson could be worth the suffering they inflict.

Some theists respond with a natural-law theodicy: plate tectonics helps make Earth habitable through carbon cycling and a stable atmosphere. This has some force, but an all-powerful God is not bound by engineering trade-offs. He could create a habitable planet without lethal tectonic activity.

Biological and Genetic Suffering

About 400,000 children are diagnosed with cancer worldwide each year. Tay-Sachs disease destroys an infant’s nervous system over two to four years, causing blindness, seizures, and death by age five. Harlequin ichthyosis leaves newborns with thick, cracked skin plates that invite fatal infection. These conditions come from mutations, chromosomal errors, and the basic mechanics of cell biology. They are not punishments, not character-building exercises, and not the result of free will.

Parasitism

The natural world contains organisms whose whole 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 over weeks of agony. Naegleria fowleri, the brain-eating amoeba, enters through the nose and destroys brain tissue with a fatality rate above 97%. The ichneumon wasp lays 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 believe a good God would have designed it. If God designed this system, he engineered suffering with extraordinary precision.

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 has no 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 - blaming Satan for corrupted nature invokes supernatural agents with no evidence to explain things physics and biology already explain. 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 about 540 million years since the Cambrian explosion. Over 99% of all species that have ever lived are now extinct, each extinction often involving long suffering before the species died out. The Permian-Triassic extinction wiped out about 96% of marine species 252 million years ago. The K-Pg extinction that ended the dinosaurs 66 million years ago caused mass ecological collapse.

Darwin felt this problem keenly. 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 all-powerful God chose evolution as his method, he picked the most suffering-saturated process available, ran it for over half a billion years, and aimed it mostly at creatures who could not learn from or even understand their own pain.

The Problem of Scale and Distribution

The argument gains more force from the pattern of suffering. It does not fall on the guilty in proportion to their guilt, or even randomly across the population. It hits the most vulnerable hardest: 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 pattern is exactly what we would expect from an indifferent universe ruled by physical laws, and exactly what we would not expect from one overseen by a just, loving God. The Problem of Hell extends this concern, asking whether eternal punishment for finite sins fits with divine justice.

Major Theistic Responses

The Free Will Defense

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

This response has real force for moral evil - the evil humans inflict on one another. But it has serious limits. It does not explain natural evil at all. Earthquakes and childhood cancers have nothing to do with human choice. Some theists extend the defense to fallen angels corrupting nature, but this invokes beings with no evidence to explain things physics already explains.

Soul-Making Theodicy

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

This has 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 all-powerful God could create beings with mature moral characters without using centuries of agony as a teaching tool.

Skeptical Theism

Skeptical theism - the view that we can’t expect to understand God’s reasons - argues that our minds are too limited to judge whether any evil is truly pointless. God may allow suffering for reasons beyond human grasp, just as a child cannot understand why a parent allows painful medical treatment.

This is perhaps the most resilient response because it cannot be disproved - no evidence can refute the claim that God has unknowable reasons. But that is also its biggest weakness. If God’s reasons are permanently hidden, suffering can never count as evidence against God, and the theist’s position becomes immune to any observation at all. Many philosophers see this as too high a price, since it removes our ability to reason about God’s nature from the world we see.

Greater Good Theodicies

Some theists argue that every instance of evil is needed for some greater good. A world without suffering would lack 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 must apply to every instance of suffering, no matter how extreme. Was the Holocaust needed for some greater good? Were centuries of child mortality before modern medicine justified by eventual medical advances that an all-powerful God could have given through revelation? The more extreme the suffering, the harder it is to claim God had no better option.

The Problem of Evil and Evolution

The discovery of evolution by natural selection deepened the Problem of Evil. As shown above, evolution runs on competition, predation, disease, and mass extinction over hundreds of millions of years. Some theistic evolutionists argue this process produces goods that could not exist otherwise - biodiversity, ecological complexity, and beings capable of real creativity. But omnipotence means the power to achieve any logically possible outcome. If complex life is logically possible without predation, parasitism, and mass extinction, then an all-powerful God could have achieved it painlessly. The Argument from Poor Design backs this up: evolution’s products show the marks of an undirected, trial-and-error 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 tries to resolve it. It pairs naturally with the Problem of Divine Hiddenness - if God 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 backs it up with specific design failures in biology.

Pro-God arguments like the Fine-Tuning Argument face a tension here: if the universe was fine-tuned for life, it was also fine-tuned for a world full of suffering. A fine-tuner powerful enough to set the cosmic constants could have also tuned them to produce less pain.

Our Scoring

Soundness: 80/100. This is the highest soundness score on the site. The evidential version, led by William Rowe, remains compelling and largely unresolved. The premises are empirically grounded: evil exists, its scale is staggering, and much of it appears pointless. Skeptical theism offers a logical escape 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 accounted for the full scope and distribution of suffering. The score is not 100 because the argument targets a specific definition of God (all-powerful, all-knowing, all-good) rather than all conceptions, and skeptical theism remains a logically available (if costly) response.

Personal God: 10/100. This is a devastatingly low score. The Personal God - all-powerful, all-knowing, all-good, and actively involved 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 perfect goodness. A morally neutral or indifferent creator could have built a universe with suffering and no moral contradiction. The score is still low because the sheer pointlessness 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 concern 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 duties toward creatures. The score is higher than the Creator because an impersonal force is not “designing” suffering but only underlying a reality that happens to contain it. The score stays below 50 because even an impersonal higher power is hard to reconcile with a universe where suffering is so widespread and seemingly purposeless.