There may be no greater challenge to belief in a sovereign, morally benevolent God than the problem of suffering and evil. Indeed, for many, it is this problem which makes belief in God and faith in the goodness of such a Being intellectually and morally impossible. Theistic religions like Judaism, Christianity, and Islam face a particularly difficult challenge in coming to terms with this problem. The challenge turns on an apparent contradiction between the facts of human experience (we suffer and feel pain, and sometimes for no known reason or explicable purpose) and belief in a sovereign, morally virtuous God.
Writing in the 18th Century, the Scottish philosopher David Hume succinctly formulated this challenge in the following trilemma:
Is God willing to prevent evil, but not able? Then is God impotent.
Is God able, but not willing? Then is God malevolent.
Is God both willing and able? Whence then is evil?
Hume’s trilemma turns the problem of suffering and evil into both an existential and a moral problem. It drives a wedge between the human existential experience of misery on the one hand, and the Simplicity Doctrine’s equation of God’s essence and God’s existence such that God always acts with one will for the good of human beings on the other hand. God’s moral character and God’s agency are both called into question in such a way that one must choose between either Divine Sovereignty or the Moral Attributes of God. Whereas the Simplicity Doctrine holds that the two form a unity, Hume’s trilemma says that there is little analogical correspondence between what theists believe about God’s moral agency and what human beings morally require from each other. In other words, when simultaneously confronted with the existential realities of misery and the claims of the Simplicity Doctrine, human beings are forced to hold a sovereign God less morally accountable than they would hold ordinary human beings.
Given Hume’s view that ethics is grounded in sentiment or sympathy, he expects this to offend his reader’s moral sentiments, thereby giving rise to the response of moral repulsion from such a Being. This moral repulsion calls into question whether it makes any sense to call God “sovereign” at all. And if God loses sovereignty, does it make sense to consider such a Being to be God in the first place?
Hume’s trilemma places the problem of evil squarely in the center of religious discourse. It becomes the religious problem. Because Hume formulates the problem of evil as both an existential and a moral problem, rationalist responses a la Descartes or Leibniz, while admittedly self-contained and perhaps even philosophically persuasive, beg the question. Since Hume shifts the grounds for moral sympathy with God, the trilemma poses the challenge of coming to terms with the disjunction between the Simplicity Doctrine and the realities of human life and experience.
It is not my intention to resolve Hume’s trilemma. Rather, I cite it in order to acknowledge the seriousness of the issues it raises, and also to suggest that it clarifies some of the reasons why intelligent, morally good persons may opt for atheism or skepticism. It's not necessarily because they're anti-religious bigots.
In my next posting, I will turn to the ways in which the Bible grapples with the problem of suffering and evil. As will be seen, scripture offers no single solution or simple answers to the complex questions raised by this problem.
 David Hume, Dialogues Concerning Natural Religion , in Writings on Religion, edited by Anthony Flew (Open Court, 1992), p. 261. For the sake of readability, I’ve changed the masculine pronouns in the original text to the word “God.”
The Simplicity Doctrine holds that God's existence and God's essence form a unity such that God does not merely possess attributes such as goodness, mercy, justice, love, etc.; rather, God is good, merciful, just, loving, etc. Furthermore, all of these properties form a unity such that no internal divisions exist within God. A classic presentation of the Simplicity Doctrine may be found in Thomas Aquinas' Summa Theologica, I, q. 3: "On the Simplicity of God," in Introduction to Thomas Aquinas, ed. Anton C. Pegis (Modern Library, 1948), pp. 28-33. Aquinas' subsequent discussion of God's attributes, God's knowledge, and God's will depends upon the Simplicity Doctrine.