The Irenaean theodicy is an argument, originally developed by St. Irenaeus that claims that the evil in the world is not incompatible with a benevolent God, because the evil serves a purpose. Recently this has been developed by John Hick, who found the Augustinian theodicy to be insufficient.
Unlike the Augustinian theodicy, Hick's Irenaean theodicy is fully compatible with a 21st century worldview that involves the gradual development of man through a process of evolution. In addition to this, it deals with natural evil, and not just moral evil.
Hick argues that a struggle for moral development is inherently better than merely to be created as morally perfect beings. In order to facilitate this "struggle" God created man at an epistemic distance. This enables free will, as to encounter God directly would destroy the potential for faith (by which I mean belief without certain cause), and so also eliminate free will.
Man must struggle to live in the world. He is beset by simple concerns such a need for food, shelter and rest, which prevent a focus on purely moral matters. Struggle against these factors creates the greatest good. The conditions that we interpret as evil are caused by God, as they facilitate this moral development by provoking thought.
The most obvious problem with this is that of apparently arbitrary evil. How can a person achieve moral development if they die as a baby? And how can atrocities such as the Holocaust be dismissed merely as tools which encourage moral thought? There are two ways in which this problem can be dealt with.
The first of these is some form of life after death. This solves the imbalance of evil that different people suffer from in life. Either imbalances can be corrected, or the ifinite bliss of a heavenly existence makes the sufferings of one's earthly life irrelevant.
The other possibility is that since God has a greater understanding of what is good and evil, and therefore it is not our place to judge his actions with relevance to these concepts. It may even be that good is defined by God, and so it is a logical impossibility for him to be otherwise.
Sources:
- http://www.faithnet.org.uk/irenaeantheodicy.htm
- http://www.philosophyonline.co.uk/pages/irenaean.htm
- Reason and Religious Belief - Michael Peterson
- The Question of God - Michael Palmer