In Unnatural Death Philip Porter demonstrates sin and death to be intimate with one another; because of sin, creation is held in thrall by death. Demonstrating the intimacy of sin and death matters because Christians should take natural science seriously while also affirming essential doctrinal claims such as "The last enemy to be destroyed is death" (1 Cor 15:26). Death is not benign, and this book provides a robust theological grammar of scriptural interpretation, of voluntary and natural evils, and of time and eternity which allows Christians to claim that the damage done by death originates in creaturely sin.

Porter argues that using Augustine's theory of the rationes seminales makes available new descriptive possibilities in the theology of creation. One way to understand this work is as a speculative picture of creation that accounts for death on evolutionary timescales without attempting to naturalize it. It offers this picture by showing how the angelic fall can account for the presence of death in creation. This work does not offer a theodicy. Instead it provides an analysis of the angelic fall that shows how God works through creaturely freedom to bring about goods that neither justify nor make sense of evil.