The problem of evil is Christianity's most serious challenge. Plantinga's Free Will Defense has dissolved the logical problem. The cross answers the existential one. And the very premise of the argument — that suffering is genuinely wrong — presupposes the moral standard only God explains.
Key claims
—Plantinga's Free Will Defense: omnipotence cannot guarantee genuinely free choices
—Evan Fales (atheist): Plantinga has convinced most philosophers — logical problem is dissolved
—The cross means God suffered — he is not a spectator of human pain
—The resurrection means suffering does not have the final word
—Evil as an argument against God presupposes the objective moral standard only God provides
—Lewis: "What was I comparing this universe with when I called it unjust?"
The strongest argument against God is not cosmological or philosophical. It is personal. It is a child with cancer. It is the Rwandan genocide. It is Auschwitz. It is the earthquake that kills ten thousand people in their sleep. It is the question that arrives at 3 AM and will not be reasoned away: if a God of infinite power and infinite goodness exists, why does he allow this?
This is not a question to be deflected. The problem of evil and suffering is the most serious intellectual and existential challenge to Christian faith, and it deserves a direct, unflinching answer. Christianity does not pretend the problem is easy, or that the answers are complete. But it does have answers — and they are more substantial than either suffering or believers typically acknowledge.
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Two versions of the problem: logical and evidential
There are two distinct forms of the problem of evil, and they require different responses.
The logical problem (the stronger form): God and evil are logically incompatible. An omnipotent, omniscient, omnibenevolent God would have the power to prevent evil, the knowledge to know about it, and the goodness to want to prevent it. Therefore, if God exists, evil would not exist. Evil exists. Therefore God does not exist.
This form of the argument was the dominant version in philosophy through the mid-twentieth century. It was effectively dismantled by Alvin Plantinga's Free Will Defense, published in its mature form in God, Freedom, and Evil (1974). Plantinga showed that the argument contains a hidden assumption: that an omnipotent God can create genuinely free creatures who always choose what is good. Plantinga argued — and virtually all subsequent philosophers have agreed — that this assumption is false. Creating genuinely free beings and guaranteeing they always choose rightly is not a coherent description of power. It is a contradiction. A being that is guaranteed to always choose rightly is not free in any meaningful sense.
The Free Will Defense
P1A world containing creatures who are free to choose good or evil is, all else being equal, more valuable than a world of non-free creatures who always do right.
P2Even God cannot create genuinely free beings and simultaneously ensure they always choose good — this is not a limitation of power but a logical impossibility.
P3God created a world with genuinely free creatures.
∴The existence of moral evil (evil resulting from free choices) is compatible with the existence of an omnipotent, omnibenevolent God.
Plantinga has convinced the philosophical community — or at least most of it — that the free will defense successfully rebuts the logical problem of evil. The deductive argument from evil is now largely abandoned by atheist philosophers.
Fales is an atheist philosopher who disagrees with Plantinga on almost everything else. His concession here is honest philosophy in action.
The Free Will Defense addresses moral evil — suffering caused by human choices: war, murder, abuse, betrayal. It does not straightforwardly address natural evil — suffering caused by non-human forces: disease, earthquakes, floods, cancer. This is where the logical problem still has some residual force, and where Christian responses are less complete. Different theodicies attempt to address natural evil — the soul-making theodicy of John Hick, the natural law theodicy of Richard Swinburne, the greater goods theodicy — but none of them provides a fully satisfying answer. Christianity does not claim to offer a full philosophical resolution to natural evil. What it claims is that the logical incompatibility between God and evil has been dissolved.
The evidential problem (the more common modern form): Even if God and evil are logically compatible, the sheer amount, distribution, and seemingly pointless nature of suffering in the world makes the existence of a good God improbable. The question is not whether God and evil can coexist, but whether a good God would permit this much suffering.
The response to the evidential problem is an appeal to epistemic humility: we are not in a position to survey all the goods that God could bring from suffering, any more than a child is in a position to understand why a parent allows a painful medical procedure. The child's experience of pointless suffering does not establish that the suffering actually is pointless — only that the child cannot see the point. Our inability to see a sufficient reason for suffering does not mean no sufficient reason exists.
This is not a dismissal of suffering. It is a recognition of the limits of our vantage point. An omniscient God, by definition, has access to moral facts, causal consequences, and possible worlds that we do not. Our judgment that suffering is gratuitous is made from a position of radical epistemic limitation.
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The cross as God's answer
The distinctively Christian response to suffering is not philosophical. It is historical.
Christianity does not offer a theodicy that explains away pain. It offers a God who entered pain. The incarnation — God becoming a human being — means that the Creator of the universe chose to experience hunger, thirst, exhaustion, grief, rejection, betrayal, torture, and death. He was not a spectator of human suffering watching from a safe distance. He was a participant.
On the cross, Jesus cried out the opening words of Psalm 22: "My God, my God, why have you forsaken me?" (Matthew 27:46). This is not a proof that God does not exist. It is a record of God experiencing, from the inside, the worst form of the very question we are asking. The God of Christianity is not immune to the problem of evil — he walked into the middle of it.
The resurrection then provides the answer the cross poses. Suffering does not have the last word. The worst that human cruelty and cosmic indifference could do — the unjust execution of an innocent man — was reversed. The grave was not the end. This is not a promise that suffering in this life will always be reversed or explained. It is a promise that the story does not end with suffering.
Not that I am (I think) in much danger of ceasing to believe in God. The real danger is of coming to believe such dreadful things about Him. The conclusion I dread is not, 'So there's no God after all,' but 'So this is what God's really like. Deceive yourself no longer.'
Lewis wrote A Grief Observed after the death of his wife from cancer. It is the most honest engagement with the emotional problem of evil in Christian literature — not a philosophical defense of God but a raw account of what it feels like when suffering becomes personal. He did not arrive at easy answers. But he arrived at trust, and his account of the journey is itself one of the most compelling pieces of evidence for the resilience of the Christian faith under real conditions.
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Evil as evidence for God
There is a final, counterintuitive observation about the problem of evil: the very premise of the argument assumes something that requires God to be true.
To say that evil exists is to say that something is genuinely wrong — not merely painful, not merely unpreferred, but actually, objectively wrong. The Holocaust was not merely disliked by a large number of people. It was evil. But as we established in Section 03, objective moral reality requires a moral lawgiver. The outrage that drives the problem of evil — the sense that a world with this much suffering ought not to exist — presupposes an objective standard of how the world ought to be. And that standard presupposes a moral God.
My argument against God was that the universe seemed so cruel and unjust. But how had I got this idea of just and unjust? A man does not call a line crooked unless he has some idea of a straight line. What was I comparing this universe with when I called it unjust?
The person who uses evil as an argument against God is, in the very act of making that argument, appealing to a moral standard that only makes sense if God exists. The argument, pressed far enough, turns back on itself.
This is not a dismissal of the emotional weight of suffering. The child dying of cancer is not an abstraction, and no philosophical argument makes it one. But it is an observation that the moral seriousness with which we respond to evil is itself a datum that points toward the moral God Christianity describes — not away from him.