 Second-century philosopher and theologian Irenaeus, after whom the theodicy is named, proposed a two-stage creation process in which humans require free will and the experience of evil to develop.Another early Christian theologian, Origen, presented a response to the problem of evil which cast the world as a schoolroom or hospital for the soul; theologian Mark Scott has argued that Origen, rather than Irenaeus, ought to be considered the father of this kind of theodicy.Friedrich Schleiermacher argued in the nineteenth century that God must necessarily create flawlessly, so this world must be the best possible world because it allows God's purposes to be naturally fulfilled.