Why did Voltaire satirize Leibniz’s best-of-all-possible-worlds idea in Candide?

Voltaire satirized Gottfried Wilhelm Leibniz’s doctrine of the "best of all possible worlds" in his 1759 novel Candide as a direct rejection of metaphysical optimism in the face of undeniable human suffering.12

Leibniz argued that because God is omnipotent, omniscient, and omnibenevolent, he must have chosen to create the best possible world from an infinite number of options. Voltaire found this philosophical justification for evil—a form of theodicy—to be absurd and morally offensive when confronted with real-world atrocities.123

Voltaire’s critique was fueled by catastrophic events of the mid-18th century, most notably the Lisbon earthquake of 1755, which killed tens of thousands of people, as well as the horrors of the Seven Years’ War. In Candide, Voltaire portrays a world governed by chaotic, blind, and often malevolent forces rather than divine order. Through the character of Pangloss, who mindlessly repeats that "all is for the best," Voltaire lampoons the disconnect between abstract philosophical optimism and the harsh realities of war, slavery, and natural disaster. Ultimately, he advocates for a practical approach to life, famously concluding that one must "cultivate one’s garden" rather than rely on empty metaphysics.2