"Experiments of theodicy," otherwise experiments of justification of God, Leibniz is the most important study of the question of how evil is possible in a world that God does not intend to leave. Leibniz breaks down the notions of omnipotence, justice and the mercy of God and shows the existential meaning of evil and death as an opportunity for personal choice. Evil is inescapable, but defeating it is the only guarantee of becoming a person. The problems posed by Leibniz are important to contemporary philosophy's debate about religion and atheism, about freedom and necessity, about inevitably evil choices (the "trolley problem") and moral trial, and the exploration of other torturous questions.