The Problem of Evil

The argument, stated fairly

The problem of evil is unique among the arguments on this site in that it runs in the opposite direction: rather than an argument for God, it is a philosophical case against the existence of an all-powerful, all-knowing, and perfectly good deity. It was articulated by the ancient Greek philosopher Epicurus, refined by David Hume and John Stuart Mill, and remains the argument that most atheists find most persuasive.

The core tension is simple. If God exists and is omnipotent, he can prevent any suffering. If he is omniscient, he knows about every instance of suffering. If he is omnibenevolent, he wants to prevent suffering. Yet suffering — on an almost incomprehensible scale — plainly exists. Children die of cancer. Earthquakes bury thousands. Animals have been living and dying in agony for hundreds of millions of years. If a being with the power, knowledge, and will to prevent all of this chose not to, what can we reasonably call that being?

The logical problem of evil

Philosophers distinguish between two versions of the argument. The logicalproblem of evil, associated with the philosopher J.L. Mackie, argues that the existence of evil is logically incompatible with the existence of an omnipotent, omniscient, omnibenevolent God. The claim is that the two propositions — “God of this description exists” and “evil exists” — cannot both be true. If one is true, the other must be false.

Most contemporary philosophers, including many atheists, concede that the logical problem is not quite airtight. It’s logically possible that God has morally sufficient reasons for permitting evil that are beyond our comprehension. We cannot rule that out. This is why the debate has largely shifted to the evidential version.

The evidential problem of evil

The evidentialproblem of evil, developed most rigorously by the philosopher William Rowe, does not claim that evil makes God’s existence logically impossible — only that it makes it highly unlikely. The argument focuses on what Rowe called “gratuitous evil”: suffering that serves no discernible purpose and whose prevention would not cost any greater good.

Consider a fawn caught in a forest fire, dying slowly over several days in agony, seen by no one. What greater good does this serve? There is no free will to be exercised, no lesson to be learned, no soul to be refined. The suffering simply is — pointless, unwitnessed, and unredeemed. The evidential argument says: the sheer quantity and apparent gratuitousness of suffering in the world constitutes strong evidence against the existence of a God who cares about every creature.

The free will defense

The most common theistic response to the problem of evil is the free will defense, associated in its modern form with the philosopher Alvin Plantinga. The argument is that God created beings capable of genuine moral choice — and genuine moral choice requires the possibility of choosing evil. A world of creatures who can only do good is a world of puppets, not persons. The suffering caused by human evil is thus the price of genuine freedom, and a world with free persons who sometimes do evil may be better than a world of moral automatons who never can.

This is a serious argument and it has genuine force when applied to moral evil — war, genocide, cruelty. But it faces a serious limit: it does nothing to explain naturalevil. Earthquakes, tsunamis, childhood leukemia, and the five-year-old child born with a painful terminal illness have nothing to do with human free will. No human chose to produce these things. If God could have created a universe without tectonic plates that kill tens of thousands, or without viruses that destroy infant nervous systems, and chose not to — free will provides no explanation.

Theodicy and its limits

A theodicy is a defense of God’s justice in the face of evil — an attempt to explain why a good God permits the suffering we observe. Theodicies come in several forms. The “soul-making” theodicy, associated with the philosopher John Hick, argues that suffering is necessary for the development of virtues like courage, compassion, and resilience. We cannot become fully human without adversity. God therefore permits suffering as a condition of genuine moral and spiritual growth.

There is something to this. We do recognize that some suffering builds character and that a world without any hardship would produce shallow people. But the objection is one of degree. The soul-making theodicy might explain moderate adversity. It does not obviously explain the Holocaust, the Lisbon earthquake of 1755 (which killed sixty thousand people and which prompted Voltaire’s famous attack on theodicy in Candide), or the death of an infant from a painful disease before she can form a single memory. At some point, the gap between “suffering that builds character” and the actual distribution of suffering in the world becomes very hard to bridge.

Another theodicy appeals to divine mystery: God’s reasons for permitting suffering are beyond human understanding. We are not in a position to judge whether the suffering we observe is genuinely gratuitous, because we cannot see God’s purposes. This response has the virtue of being unfalsifiable — which is precisely the problem with it. An explanation that can accommodate any evidence whatsoever is not really an explanation. And it places an extraordinary demand on the bereaved: not merely to accept their loss, but to trust that it was somehow necessary within a plan they cannot see.

Why many find this argument decisive

The problem of evil is not merely a philosophical puzzle. For many people, it is a lived experience. It is the moment when a believer, standing at a graveside or sitting in a hospital room, finds that the theological answers they were given are simply not adequate to what they are witnessing. This is not a logical failure — it is a moral one. The God being defended in theodicy begins to seem less like a loving father and more like an entity whose goodness is defined in ways that bear no resemblance to what we ordinarily mean by the word.

The philosopher Stephen Fry, asked what he would say to God at the gates of heaven, replied: “Bone cancer in children — what’s that about? How dare you create a world in which there is such misery that is not our fault? It’s not right.” The sentiment is not a philosophical argument in the technical sense, but it captures something the theodicies tend to miss: there is a moral demand being made of God, not just an epistemic one. And many people, on reflection, find that demand unmet.

No theodicy has achieved wide acceptance even among religious philosophers. The problem of evil remains open — and it is the argument that, more than any other, has led thoughtful people out of belief.