Theodicy

The Essais de Théodicée, published in 1710, is Gottfried Wilhelm Leibniz‘s major work on the Problem of Evil. The book introduces the word “theodicy” to philosophy. Its central thesis, that the actual world is the best of all possible worlds, has been mocked since Voltaire and is now mostly cited only to be dismissed.

The structural move is what survived. Leibniz argued that defending the goodness of God against the existence of evil requires reasoning about possible worlds, weighing this world against the alternatives that an omnipotent being might have actualized instead. The argumentative apparatus, that we should evaluate divine choice across modal alternatives rather than against an unspecified ideal, is the same apparatus Alvin Plantinga uses in the Free Will Defense, even where Plantinga’s specific conclusions differ.