The Irenaean theodicy is challenged by the assertion that many evils do not promote spiritual growth, but can instead be destructive of the human spirit. Hick acknowledges that this process often fails in our world. Horrendous suffering often leads to dehumanization, and its victims become angry, bitter, vindictive and spiritually worse. Yet, life crises are a catalyst for change that is often positive. Neurologists Bryan Kolb and Bruce Wexler indicate this has to do with the plasticity of the brain. The brain is highly plastic in childhood development, becoming less so by adulthood once development is completed. Thereafter, the brain resists change. The neurons in the brain can only make permanent changes "when the conditions are right" because the brain's development is dependent upon the stimulation it receives. When the brain receives the powerful stimulus that experiences like bereavement, life-threatening illness, and other deeply painful experiences provide, a prolonged and difficult internal struggle, where the individual completely re-examines their self-concept and perceptions of reality, reshapes neurological structures. The literature refers to turning points, defining moments, crucible moments, and life-changing events. These are experiences that form a catalyst in an individual's life so that the individual is personally transformed, often emerging with a sense of learning, strength and growth, that empowers them to pursue different paths than they otherwise would have.
