Ivan's challenge is do date the only realistically plausible counter to Irenaean theodicy and Hick's theory of soul making. The work of Dostroyevsky, a Christian himself, Ivan's challenge, as set out in the novel Brothers Karamazov, states how that even though God may allow suffering to permit human moral development, this is not justified due to the proportionally great amount of suffering experienced, often by those considered unaware innocents, who will neither learn from the suffering they endure ,or develop morally from it.
As an example the fictional character Ivan describes how the suffering of children is evil and cannot possibly be the product of a loving God's plan for human moral awareness leading to the development of the Summum Bonum. He states that any such possible utopia in the future will never justify suffering occuring in the present.
Irenean theodicy typically aboslves God from any wrong doing in permitting evil, maintaining that his innaction and separation from the world, the epistemic distance is necessary to allow humans free will to act as they choose. It argues that human ability to determine ones ability is sacrosanct and must be preserved at all costs.
Ivan's challenge however disagrees with this - modern philosophy has created an exposition of the argument:
Consider for a moment standing next to the lime pits at Treblinka, where SS troops throw children alive in to the pits of the dead and dying, simply in order to save on gas. Stand there and then declare that it is worth this happening for your freedom to choose, your liberty of indifference. Watch them be kicked back in to the pits if they climb out and say you reserve your right to freedom even in the face of this.
Alternatively consider the mass rape of 13 and 14 year old girls in the former Yugoslav by invading soldiers: would you still have the same belief in the fundamental goodness of God after watching whilst their commanders looked on and encouraged them. Would it not be hard in this light to argue that humans should be allowed the liberty to do this - and that for some reason by allowing it we will morally develop?
Ivan's challenge argues that if humans are allowed to commit these acts, then God is evil for not preventing them. If God however does not permit these acts then he limits human freedom and so negates any sense of morality - if we cannot choose immorality we cannot understand the concept of moral conduct at all (Kant's postulates).
Fortunately for theologians less prevalent, but more defensible theodicies
exist to defend the necessity of evil. Whilst not as discussed as Augstinian
and Irenaen theodicy they certainly stand up to criticisms like the above more strongly.