The Problem of Evil

In brief

The problem is easy to state and hard to answer. Suppose God is omnipotent (able to do anything), omniscient (aware of everything), and wholly good (wanting the good and hating the bad). Now look at the world: children die of bone cancer, earthquakes bury the innocent, people are tortured. A being with the power to stop this, the knowledge that it is happening, and the goodness to care would seem to stop it. It has not been stopped. So either no such being exists, or the three attributes do not fit together as advertised. The earliest surviving version is credited to Epicurus (341 to 270 BCE): is God willing to prevent evil but not able? Then he is not omnipotent. Able but not willing? Then he is not good. Both able and willing? Then where does evil come from? The defenses mounted against this challenge are called theodicies, from the Greek for justifying God.

The full treatment

Two problems, not one

Philosophers separate two distinct arguments that often get run together. The logical problem claims that the propositions "an omnipotent, omniscient, wholly good God exists" and "evil exists" are flatly contradictory, so no rational person can hold both. J. L. Mackie pressed this in his 1955 paper "Evil and Omnipotence," arguing that a good, all-powerful being would eliminate evil as far as it could, and there are no limits on what an omnipotent being can do, so the existence of any evil disproves such a God outright.

The evidential problem (also called the probabilistic or inductive problem) is more modest and, most philosophers now think, more dangerous. It grants that the two claims are not strictly contradictory, but argues that the amount, distribution, and apparent pointlessness of suffering make God's existence improbable. William Rowe's 1979 formulation is the standard: a fawn burned in a forest fire, dying slowly over days with no human to learn from it and no discernible greater good served, is evil that appears gratuitous. If even one instance of suffering is genuinely pointless, a perfect God who prevents needless suffering would not have allowed it.

The free will defense

The most influential reply to the logical problem is Alvin Plantinga's Free Will Defense, set out in God, Freedom, and Evil (1974). Plantinga's aim is narrow but decisive: he does not try to explain why God permits evil (that would be a theodicy), only to show that the coexistence of God and evil is logically possible. His move: a world containing free creatures who sometimes choose good is more valuable than a world of puppets, but genuine freedom means God cannot guarantee that free creatures always choose rightly. It is possible that every creaturely essence God could have created would go wrong in some world (Plantinga calls this "transworld depravity"). If so, God could not create a world with free good agents and no moral evil. Most philosophers, including Mackie's successors, concede that this defeats the logical problem: the mere existence of evil is not a contradiction.

Soul-making and skeptical theism

The evidential problem is harder, and theists answer it in two broad ways. The first offers a positive theodicy. John Hick, in Evil and the God of Love (1966), revived a line traced to the early theologian Irenaeus (c. 130 to 202 CE): the world is not meant to be a hedonic paradise but a "vale of soul-making," an environment of real risk and hardship in which persons grow into moral and spiritual maturity. Courage, compassion, and forgiveness are impossible without danger, need, and wrong to forgive. A world without suffering would be a world without the goods that suffering makes possible.

The second answer refuses to explain and instead attacks the inference. Skeptical theism, developed by Stephen Wykstra (his 1984 "CORNEA" argument) and William Alston, concedes we cannot see the point of much suffering, but denies that this shows there is no point. Given the gap between a divine and a human mind, our failure to detect a justifying reason is weak evidence that none exists, much as a novice's failure to see why a grandmaster made a move is no evidence the move was bad. Rowe's leap from "no good we can see" to "no good there is" is precisely what the skeptical theist blocks.

A distinction that matters: moral versus natural evil

Free will defenses address moral evil, the harm done by free agents: cruelty, betrayal, murder. They say much less about natural evil, the suffering caused by disease, famine, and disaster, where no free choice is in view. This is why the problem does not dissolve with the free will move. Theists extend the defense (perhaps natural evil is the work of non-human free agents, or the price of a stable law-governed universe in which we can act at all), but here the answers grow more speculative, and the evidential problem bites hardest.

Lineage

The dilemma is ancient. Its earliest surviving statement comes to us through the Christian writer Lactantius (c. 314 CE), who quotes it to attack Epicurus, though scholars debate whether Epicurus framed it exactly so. The problem sharpens only for religions with a single perfect God, so it presses on Judaism, Christianity, and Islam far more than on polytheism or on traditions like some schools of Buddhism where no omnipotent creator is posited. The Book of Job is an early wrestling with unjust suffering that pointedly refuses a tidy answer. The word "theodicy" was coined by Gottfried Leibniz in 1710, who argued this is the "best of all possible worlds," a claim Voltaire savaged in Candide (1759) after the Lisbon earthquake of 1755 killed tens of thousands, many at prayer. The definitive modern statement is David Hume's, put in the mouth of Philo in the Dialogues Concerning Natural Religion (published 1779): the misery of the world is exactly what we would not expect from infinite power joined to infinite goodness. It connects to the broader dispute in arguments-for-god, and it presupposes that goodness is a real standard God answers to, the very issue raised by the-euthyphro-dilemma.

The strongest case for it

The evidential version is strong because it needs so little. It does not require proving a contradiction; it only requires that some suffering appears to serve no outweighing good, and that a perfect being would not permit pointless suffering. Both premises are hard to deny. The scale and character of the evidence are staggering: not just human cruelty, which free will might cover, but hundreds of millions of years of animal suffering before any human existed, and forms of horror so extreme (Marilyn McCord Adams called them "horrendous evils") that they seem to destroy the very possibility of a life's being good for the one who endures it. The force is also moral, not merely logical. Dostoevsky's character Ivan Karamazov, in The Brothers Karamazov (1880), does not deny God; he says that even if suffering buys some future harmony, the torture of a single child is a ticket he respectfully returns. That refusal captures why the problem endures: it can feel not like a puzzle to solve but like a wrong that no explanation should be allowed to launder.

The strongest case against it

Defenders of theism reply on several fronts, and the best replies are serious. First, the logical problem is now widely regarded as answered: Plantinga's Free Will Defense showed that God and evil are not contradictory, a point even many atheists grant. Second, skeptical theism undercuts the evidential argument at its weakest joint. Rowe must infer from "we can find no justifying good" to "there is none," and Wykstra's response is that this inference is only as good as our reason to think we would detect such a good if it existed, which, given a mind infinitely beyond ours, we have little reason to assume. Third, theodicies supply positive candidates: Hick's soul-making, the greater goods of a law-governed world, and the free will that makes love and virtue possible. Fourth, some argue the atheist faces a mirror problem: to call the world's suffering genuinely evil, rather than merely unpleasant, arguably presupposes an objective standard of good and evil that is easier to ground in theism than without it. Marilyn McCord Adams goes further, arguing that a good God need not justify each evil by a greater good at all, but can defeat horrendous evils by giving the sufferer intimacy with God so great that they would not, in the end, wish their life otherwise. None of this closes the case, but it shows the inference from suffering to atheism is contestable at every step.

Where it stands now

The problem of evil is the most discussed argument in the philosophy of religion and, in polls of the reasons people give for unbelief, consistently the leading one. The consensus among philosophers is roughly this: the logical problem is a draw or a defeat for the atheist, since bare consistency has been shown; but the evidential problem remains live and unresolved, with skeptical theism and the various theodicies pushing back hard against Rowe-style arguments. The debate has grown more technical (over the epistemology of the "noseeum" inference, over what possible worlds an omnipotent being could actualize) and also more attentive to animal suffering and to the horrendous cases that resist any greater-good bookkeeping. It remains the sharpest test any defense of God must pass.

Test yourself

Picture the single worst instance of suffering you know to be real. Now ask two separate questions. Could there be a good great enough that even a perfect being would permit it? And if there could, would you be able, from where you stand, to recognize that good if it existed? Notice that your answer to the first is a claim about what is possible, and your answer to the second is a claim about the limits of your own sight. The whole modern debate lives in the gap between them.