Voltaire wrote Candide to refute and parody Liebniz's philosophy that our world is the best one God could have created. In Candide, Liebnitz's optimism is summed up in the words of Candide's tutor, Pangloss, who constantly repeats that "all is for the best in the best of all possible worlds."
Voltaire depicts the problem in idealist philosophies like Liebniz's by illustrating how naive people like Candide are taken in by these systems of thought and then surprised when the world turns out to be overrun with evil.
Voltaire depicts evil as everywhere, in an over-the-top, exaggerated way, while creating dark humor by having the characters tell very matter-of-factly about the horrors they have survived. Evil is inherent in the human psyche, but Voltaire most particularly critiques the way European customs and institutions have exacerbated the world's evil. Voltaire particularly aims at religious hypocrisy, along with militarism, colonialism, violence, greed, ambition, and enslavement.
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