The problem is ancient and brutal. If a creator god is all-powerful, all-knowing, and all-good, then suffering shouldn't exist — or, where it exists, it should serve a purpose proportionate to its cost. Yet children die of cancer, earthquakes bury villages, and millions starve. Either God isn't all-powerful, or isn't all-good, or has reasons we can't see. Each option costs something significant.
The standard defenses are old and refined. The free-will defense (Augustine, Plantinga): evil comes from human choice, not God; a world with genuine freedom is worth the cost. The soul-making defense (Hick): suffering forms character that couldn't form otherwise. The skeptical theist: God's reasons exceed our grasp; we have no standing to call the picture incoherent.
David Hume, Voltaire, and Dostoevsky each found these defenses wanting. Hume noted that a competent designer could have built a world with the same moral lessons and less unnecessary cruelty. Voltaire's *Candide* made the soul-making defense look obscene in the face of actual mass death. Dostoevsky's Ivan Karamazov returns the ticket of admission — declines a salvation built on the suffering of even one tortured child. The problem is not solved; the most honest theists treat it as a wound that lives alongside faith, rather than a puzzle that yields to argument.