Bayle was the great adversary of Leibniz’s theodicy, and it was only when faced with Bayle’s reprimands against every possible theological justification of evil that Leibniz completely developed his own theory. The Theodicy was written, in fact, as a continual counterpoint to Bayle’s arguments in the Dictionnaire historique et critique and other works. Bayle indicated the bankruptcy of any rational theology in confronting the question of evil, suggesting to the faithful the renunciation of every real cognitive content of their belief, and reducing it to mere empty faith. Christian theology thus became incapable of distinguishing itself from deism or atheism, from which it was separated only by a ‘dispute de mots’. It was the moral attributes of God in particular which Bayle considered completely ungraspable; and this was the challenge which Leibniz sought to take up, revisiting with courage and lucidity the arguments of both the theological and metaphysical traditions.