Following the devastating Lisbon Earthquake (1 November 1755), which occurred decades after the publication of the "Essais de Théodicée sur la bonté de Dieu, la liberté de l'homme et l'origine du mal" (1710), Leibniz's philosophical optimism and theodicy incurred considerable criticism both from his fellow Enlightenment philosophers and Christian theologians as well. Critics of Leibniz, such as Voltaire, argue that the world contains an amount of suffering too great to justify optimism. While Leibniz argued that suffering is good because it incites human will, critics argue that the degree of suffering is too severe to justify belief that God has created the "best of all possible worlds". Leibniz also addresses this concern by considering what God desires to occur (his antecedent will) and what God allows to occur (his consequent will). Others, such as the Christian philosopher Alvin Plantinga, criticized Leibniz's theodicy by arguing that there probably is not such a thing as "the best" of all possible worlds, since one can always conceive a better world, such as a world with one more morally righteous person.