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The philosophy of religion contains two closely related challenges to theistic belief, especially to the classical monotheistic traditions of Judaism, Christianity, and Islam. The problem of evil asks how a perfectly good, omnipotent, and omniscient God could permit the existence of evil and suffering. The problem of divine hiddenness asks why, if God exists and desires a relationship with every person, God's existence is not more evident. Though often treated separately, the two problems are deeply intertwined: both concern the apparent tension between God's nature and the way the world actually appears to us. Both have generated substantial literatures in analytic philosophy since the mid-twentieth century, though their roots reach much further back.
The problem of evil is not a single argument but a family of arguments. The logical problem of evil claims that the existence of any evil whatsoever is logically incompatible with the existence of an omnipotent, omniscient, perfectly good God. The evidential problem of evil makes a weaker but more widely accepted claim: that the amount, kinds, or distribution of evil in the world makes God's existence improbable, even if not strictly impossible. A further distinction concerns moral evil (harm caused by free creaturely choices) and natural evil (suffering from disease, earthquakes, or other non-human causes). Some philosophers also distinguish gratuitous evil—suffering that serves no greater good and could have been prevented without loss—from evil that might be justified by outweighing goods.
The problem of divine hiddenness, as formulated in contemporary debate, begins from a different observation. If God is perfectly loving and desires a personal relationship with every human being, then God would ensure that every person who is capable of such a relationship has sufficient evidence of God's existence to enter into it. But many sincere seekers report that they find no such evidence, or that they find the evidence genuinely ambiguous. The argument concludes that the existence of nonresistant nonbelievers—people who do not believe in God through no fault of their own—is strong evidence against the existence of a perfectly loving God.
The stakes are not merely academic. These arguments bear directly on the rationality of theistic belief, on the problem of religious diversity, on pastoral questions about suffering and doubt, and on how believers understand silence, prayer, and the apparent absence of God. For atheists, these arguments often function as the intellectual core of a positive case for unbelief. For theists, they set the agenda for theodicy (the attempt to justify God's ways to humanity) and for accounts of faith, trust, and divine communication.
The problem of evil is as old as philosophical theology itself. The ancient Greek philosopher Epicurus is often credited with an early formulation, though his exact words are lost and the argument is preserved through later doxographers. The biblical books of Job and Ecclesiastes wrestle with undeserved suffering, and the rabbinic, patristic, and Islamic theological traditions all contain sustained reflection on divine justice and human suffering. Augustine of Hippo developed the influential free will defense, arguing that evil entered the world through the misuse of creaturely freedom and that God, while permitting evil, is not its author. Thomas Aquinas integrated this with a broader metaphysical framework in which evil is a privation of good rather than a positive reality. Gottfried Leibniz coined the term "theodicy" in the early eighteenth century and argued that this is the best of all possible worlds, a view satirized by Voltaire in Candide.
These earlier thinkers did not, however, treat the problem of evil as a direct argument for atheism in the way that became standard in the twentieth century. The modern subfield is marked by a shift from defending God's justice within a framework of faith to treating the existence of evil as a potential disproof of theism that must be answered on purely philosophical grounds. This shift is often associated with the 1955 paper "Evil and Omnipotence" by J. L. Mackie, which posed the logical problem as a formal contradiction between God's attributes and the existence of evil. Alvin Plantinga's response, developed through the 1960s and 1970s, argued that the free will defense shows the logical problem to be unsound: it is possible that God could not create a world with moral good without permitting moral evil, and possible that every creaturely essence suffers from transworld depravity. Plantinga's conclusion—that the existence of God and the existence of evil are logically compatible—is now widely accepted, and the debate has largely moved to the evidential formulation.
The problem of divine hiddenness has a different trajectory. The idea that God's hiddenness is a problem appears in Pascal's Pensées, where he writes of a God who "wills to appear openly to those who seek him with all their heart" yet remains hidden from others. But the argument as a formal case against theism was developed only in the late twentieth century, most influentially by J. L. Schellenberg in his 1993 book Divine Hiddenness and Human Reason. Schellenberg's argument is distinctively modern in its emphasis on nonresistant nonbelief as a category and in its claim that a loving God would not leave sincere seekers without sufficient evidence.
Contemporary work on the problem of evil is organized around several rival research programmes, each offering a different diagnosis of the problem and a different strategy for resolving it.
The free will defense, in its contemporary form, argues that the value of creaturely freedom—specifically, the freedom to choose between good and evil—is so great that God is justified in creating a world in which that freedom is genuinely possible. The key move is to distinguish between the freedom to do otherwise and the mere appearance of choice. A world containing significantly free creatures who sometimes choose rightly is more valuable than a world of automata who always do what is right, and God cannot simply determine that creatures freely choose the good, because a choice that is determined is not free in the relevant sense.
This approach has been refined in several directions. Plantinga's version is explicitly modal: it argues that it is possible that every free creature suffers from transworld depravity, meaning that in every possible world where they make morally significant choices, they go wrong at least once. If this is possible, then God could not have created a world with moral good but without moral evil, and the logical problem fails. The greater goods defense generalizes the strategy: it claims that many evils are necessary conditions for goods that outweigh them, such as courage, compassion, or the development of moral character. The soul-making theodicy, associated with John Hick, argues that the world is best understood as a "vale of soul-making"—a place where creatures develop moral and spiritual virtues through facing challenges and overcoming them, a process that requires real obstacles and genuine risk.
The free will defense faces several persistent objections. First, it does not obviously address natural evil, since earthquakes and diseases are not caused by creaturely choices. Some theists respond by attributing natural evil to the actions of fallen angels or demons, a view that has few contemporary defenders; others argue that natural evil is a byproduct of the lawful order of nature, which is itself necessary for the existence of free creatures. Second, the defense seems to imply that God could not have created a world with free creatures who always choose rightly, a claim that is difficult to establish. Third, the amount and distribution of suffering—including the suffering of children and animals—strikes many as exceeding what any greater good could justify. This last objection is central to the evidential problem.
The evidential problem of evil, most forcefully developed by William Rowe in the 1970s and 1980s, begins from particular instances of intense, apparently pointless suffering. Rowe's famous example is of a fawn trapped in a forest fire, suffering terribly before dying, with no observer to witness it and no apparent good resulting from its agony. The argument claims that we are justified in believing that such suffering is gratuitous—that no greater good requires it—and that the existence of even one instance of gratuitous evil is incompatible with the existence of God.
The most influential response is skeptical theism, which argues that our inability to see how a particular evil serves a greater good is not good evidence that it does not. The central claim is that God's knowledge is vastly greater than ours, and that the goods and evils involved in divine providence may be so complex that we cannot grasp them. Just as a child cannot understand why a parent allows a painful medical procedure, we cannot understand why God permits particular sufferings. Skeptical theism does not claim to know what God's reasons are; it claims that our ignorance undermines the inference from "we cannot see a justifying good" to "there is no justifying good."
Skeptical theism has generated a large and intricate literature. Critics argue that it proves too much: if we cannot trust our judgments about which evils are gratuitous, we cannot trust our judgments about which goods are worth pursuing, and the position collapses into moral skepticism. Defenders respond that the argument only applies to our ability to grasp the full providential scheme, not to our ordinary moral knowledge. The debate remains unresolved, and it is fair to say that the evidential problem, together with skeptical theism, constitutes the central live controversy in the contemporary problem of evil.
A third approach attempts to provide positive accounts of why God permits evil, rather than merely defending the logical possibility of divine justification. The soul-making theodicy is one such account. Another is the natural law theodicy, which argues that a world with regular natural laws is necessary for rational agency, and that such laws will inevitably produce some suffering as a byproduct. A third is the free will theodicy in its stronger form, which claims not merely that free will is compatible with evil but that God actually created the world in order to make free creatures possible.
These theodicies face a common challenge: they must show not only that some good requires some evil, but that the specific evils we observe—their kinds, amounts, and distributions—are required for the goods in question. A soul-making theodicy, for example, must explain why the soul-making process requires the suffering of infants or the prolonged agony of the innocent. Many philosophers conclude that no theodicy has succeeded in this stronger task, and that theodicies are best understood as partial defenses rather than complete explanations.
A distinct but related issue concerns the traditional doctrine of hell. If God is perfectly good and loving, how could God consign creatures to eternal conscious torment? This problem is sometimes treated as a special case of the problem of evil, sometimes as a separate topic. Responses include annihilationism (the view that the wicked cease to exist), universalism (the view that all are eventually saved), and various free will accounts of hell (the view that the damned choose their own separation from God). The debate is complicated by the fact that the relevant biblical and traditional materials are themselves contested, and by the difficulty of reconciling any version of hell with divine goodness.
The problem of divine hiddenness is a younger subfield, and its major approaches are correspondingly less settled. The central argument, again, is that nonresistant nonbelief is incompatible with a perfectly loving God. Responses fall into several broad families.
One family of responses argues that God's self-revelation must be limited to preserve human freedom. If God's existence were overwhelmingly evident, the argument goes, we could not freely choose whether to love and obey God; the evidence would compel belief and undermine the possibility of authentic relationship. This response parallels the free will defense in the problem of evil, and it faces a similar objection: why must the evidence be so ambiguous that many sincere seekers fail to find it? Could God not reveal enough to make belief reasonable while still leaving room for doubt? Defenders of the argument from hiddenness reply that the actual degree of hiddenness far exceeds what is needed for freedom.
A second family of responses emphasizes the limits of human cognitive access to the divine. On this view, God is not hidden because God chooses to hide, but because finite creatures cannot fully grasp an infinite reality. The hiddenness of God is a necessary consequence of the creator–creature distinction, not a contingent failure of divine love. This response draws on apophatic theology—the tradition that emphasizes what cannot be said about God—and on the idea that religious knowledge is not primarily propositional but practical and relational. Critics object that this response does not explain why God could not provide sufficient evidence for belief, even if full comprehension is impossible.
A third family of responses argues that the very nature of faith requires epistemic ambiguity. On this view, faith is not belief on the basis of evidence but trust in the absence of conclusive proof. If God's existence were evident, faith would be impossible or unnecessary, and the kind of relationship God desires—one based on trust rather than certainty—could not exist. This response has deep roots in the Christian tradition, particularly in Kierkegaard, and it has been developed in contemporary philosophy of religion by thinkers who emphasize the practical and existential character of religious commitment. The objection is that this account seems to make faith a virtue only because of a defect in the evidence, and that a perfectly loving God would not design the world so that the most important relationship in human life rests on such fragile epistemic foundations.
A fourth family of responses argues that nonresistant nonbelief in this life is not ultimately incompatible with divine love, because God will provide opportunities for relationship after death. On this view, the present life is not the whole story; those who die without belief may encounter God in the afterlife, and the hiddenness of God in this life is temporary. This response has been developed in various forms, including accounts of purgatory, universalism, and the possibility of post-mortem conversion. Critics object that the argument from hiddenness is about the present evidence available to living persons, and that postponing the resolution does not address the question of why God does not provide sufficient evidence now.
The two problems are often treated separately, but they are connected in several ways. Both begin from observations about the apparent absence of God: the problem of evil observes that God seems absent from the midst of suffering; the problem of hiddenness observes that God seems absent from the minds of sincere seekers. Both problems put pressure on the claim that God is perfectly loving, and both are often answered with appeals to human freedom, divine mystery, or the nature of faith. Some philosophers have argued that the two problems are really one problem: the problem of divine hiddenness is just the problem of evil applied to the apparent evil of nonbelief. Others maintain that they are distinct, because the problem of evil concerns the distribution of suffering while the problem of hiddenness concerns the distribution of evidence.
The two problems also interact in theodicies. A theodicy that appeals to soul-making, for example, might explain hiddenness as part of the soul-making process: doubt and the search for God are themselves occasions for spiritual growth. A theodicy that appeals to free will might explain hiddenness as necessary for authentic choice. Conversely, the problem of hiddenness can be used as a test case for theodicies: if a theodicy cannot explain why God would remain hidden, it may also fail to explain why God would permit certain kinds of suffering.
The contemporary field is characterized by several features. First, the logical problem of evil is widely regarded as solved, in the sense that most philosophers accept Plantinga's demonstration that theism and evil are logically compatible. The live debate concerns the evidential problem, and here the field is genuinely divided. Second, the problem of divine hiddenness has grown rapidly since the 1990s and is now a standard topic in philosophy of religion courses and conferences. Third, the field has become increasingly interdisciplinary, drawing on cognitive science of religion (which studies the psychological mechanisms underlying religious belief), on biblical scholarship (which informs debates about the nature of divine revelation), and on comparative theology (which raises questions about whether hiddenness is a problem in non-theistic traditions).
A notable recent development is the growth of skeptical theism as a research programme, with its own technical literature on the epistemology of ignorance and the limits of human moral knowledge. Another is the increasing attention paid to horrendous evils—evils so terrible that they seem to threaten the very possibility of a meaningful life for those who suffer them—and to the question of whether any good could justify them. A third is the development of reformed epistemology, which argues that belief in God can be properly basic, not requiring evidence or argument, and which therefore changes the dialectical situation: if theistic belief is rational in the absence of evidence, then the problem of evil and hiddenness must be reformulated as challenges to the defeaters of such belief rather than as arguments against theism.
The field remains philosophically diverse. There are theists who defend traditional theodicies, theists who adopt skeptical theism, theists who embrace mystery and apophaticism, and atheists who press both the evidential problem and the argument from hiddenness. There are also philosophers who reject the terms of the debate altogether, arguing that the classical conception of God as omnipotent, omniscient, and perfectly good is itself the problem, and that a more limited or process-oriented conception of God avoids the difficulties. The debate shows no signs of resolution, and it is unlikely to do so: the problems of evil and divine hiddenness are not technical puzzles but fundamental questions about the coherence of theistic belief in a world that often seems indifferent to human suffering and human seeking.