In recent centuries the relationship between Christian theology and the prevailing political and intellectual culture has alternated on both sides between dismissal, avoidance and accommodation.
Occasionally, as in St Augustine's monumental City of God, it has been conducted as takeover. Augustine offered a magisterial account of Roman culture and its presuppositions, claiming that its contradictions and aspirations could be reconciled only on the basis of Christian faith.
James Boyce's fascinating recent history of original sin and its impact on contemporary Western culture, Born Bad, starts with Augustine. He claims that contemporary attitudes to politics, human origins, economics and human psychology can be understood only if we recognise the hidden presuppositions imported from the theology of original sin. He argues that, as the doctrine of original sin lost purchase in the churches, it tightened its grip on secular culture.
The core of original sin is that there is something broken, perverse and destructive in all human beings, tracing back to the sin of Adam and Eve, from which we need to be rescued. We cannot save ourselves through our own free choices and actions but rely entirely on God's action in Christ. The doctrine was developed in a polarised conflict that focused on the unwanted logical consequences of opposed positions. So the stock questions raises were whether non-baptised babies would go to hell, and whether God predestined some people to damnation.
With the focus in the Enlightenment on human possibility and on the capacity of human beings to shape their destiny, Western Christians became increasingly optimistic about the human condition. Original sin was seen as less radical in its effects and unyielding to human change. But secular theorists worked out of the understanding that human beings were inherently flawed and selfish.
Adam Smith appealed to the invisible hand of the market, not to celebrate it, but as a form of harm mitigation. The founding fathers of the United States Constitution saw their task as limiting the power both of flawed citizens and of flawed government. Freud postulated conflictual and destructive forces at work in human beings, offering no guarantee that therapy would set them free. Dawkin's selfish gene and the memes that civilise it are not derived from his research, but from presuppositions about human flaws from which we need to be set free.
One of Boyce's more challenging conclusions is that these theories, proposed by people who consciously tried to emancipate people from religious ideas,