In the 1950s, the logical problem of evil looked like an executioner. Then a young philosopher named Alvin Plantinga showed that the executioner had been swinging at shadows. 5 min read.
The logical problem of evil, as formulated by J.L. Mackie in 1955, is a daring piece of philosophical violence. It claims that theistic belief is internally contradictory: if God is omnipotent, he can prevent evil; if omniscient, he knows about every instance of it; if perfectly good, he wants to prevent it. Yet evil exists. Therefore, no such God can exist. This argument does not rely on evidence or probability; it is a deductive dagger. And for a while, many philosophers believed it was fatal.
Alvin Plantinga's response, developed through the 1960s and culminating in his 1974 book God, Freedom, and Evil, is not a theodicy—it does not attempt to explain why God actually permits evil. Instead, it is a defense: a demonstration that the alleged contradiction is not a contradiction at all. Plantinga's strategy is disarmingly simple. To defeat a deductive argument, you need only produce a logically possible scenario in which both premises and conclusion coexist. If such a scenario exists, the charge of incoherence collapses.
The scenario Plantinga constructs involves free will. It is logically possible that God created a world containing significantly free creatures—beings whose choices are not causally determined by prior states of the universe. Such freedom, Plantinga argues, is enormously valuable. It is the only way creatures can genuinely love, make moral decisions, and enter into a relationship with their creator. But freedom comes with a built-in hazard: a creature with genuine freedom can always choose wrongly. It is possible, in other words, that God could not have created a world with free creatures and simultaneously guaranteed that they would never choose evil. If that is right, then the existence of evil is not a logical impossibility but an unavoidable side effect of the great good of creaturely freedom.
The key insight is that possibility, not plausibility, is the entire game in the logical debate. A single possible scenario that includes both God and evil suffices to defeat the claim of outright inconsistency. Plantinga never had to prove that his story is likely true—only that it could be true.
To see the force of this move, consider the structure of Mackie's argument. It assumes that an omnipotent God could simply create any world he wanted, including a world with free creatures who always choose the good. Plantinga challenges exactly this assumption. He introduces the idea of transworld depravity: for any significantly free creature, there is at least one possible world in which that creature would freely choose evil. It may be that every creaturely essence suffers from this condition, meaning that no matter which free creatures God instantiated, some evil would result. If that is even logically possible, then God's failure to create a perfectly good world is not a mark against his omnipotence; it is a consequence of the nature of creaturely freedom.
The logical problem also made a second assumption: that a world without evil would automatically be better than a world with some evil. Plantinga's defense rejects this too. A world containing free creatures who sometimes do terrible things may be more valuable, on balance, than a world populated by automata who are programmed to do only good. Genuine love, courage, and moral growth all require freedom. The value of such a world outweighs the disvalue of the evil that freedom permits.
Does this mean the logical problem is dead? Most philosophers—including many atheists—now think so. The consensus is that Plantinga succeeded in showing that the existence of God and the existence of evil are not formally contradictory. That is a limited but crucial achievement. It does not prove that God exists, nor does it touch the evidential problem, which asks whether the actual amount and kind of suffering makes theism unlikely. But it does demolish the claim that a single, simple contradiction refutes theistic belief.
- Logical problem: God and evil cannot coexist — deductive, a priori.
- Free will defense: Shows coexistence is logically possible via creaturely freedom.
- Status after Plantinga: The deductive refutation fails, but the evidential problem remains untouched.
The free will defense is often misunderstood as a full justification of suffering. It is not. It is a narrow philosophical instrument, crafted for a specific job: showing that the logical problem's knife does not cut. Understanding this distinction is essential for anyone navigating the problem of evil, because it prevents us from attacking a straw man. The real battleground today is not logical incoherence but evidential weight. And there, the fawn in the burning forest still waits.
Referenced Works & Texts
- J.L. Mackie, Evil and Omnipotence, Mind (1955). Presents the logical problem in its most influential form.
- Alvin Plantinga, God, Freedom, and Evil (1974). The definitive statement of the free will defense.
Explore the full source material at Philosopheasy Source: Logical vs Evidential Problem of Evil: A Side-by-Side Comparison
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