G.K. Chesterton once wrote that original sin was “the only part of Christian theology which can really be proved.” His thinking here is that we are not confronted every day with virgin births or resurrections, but the evidence of human frailty is all around us. In the last few months, in this country alone, we’ve seen hundreds of allegations of rape and sexual harassment in Hollywood and Washington, and lone wolf massacres in Texas and Nevada. And that is only the tiniest part of the evil humans have done recently–man’s constant and unrelenting inhumanity to man.

The all-encompassing evil of our world is such a commonplace that it is hardly mentioned anymore outside a dwindling number of churches. Of course, people will always ask the question, Why do bad things happen? But it seems that there is a conspiracy of silence around the fact that we have a plausible answer to that question: the Christian doctrine of original sin.

The question, posed in another way, is this: Unde hoc malum? Where did this evil come from? Alan Jacobs shows us in his Original Sin: A Cultural History (HarperOne, 2009) that this is a question that all humans have asked themselves at all times. The Christian doctrine of original sin is one convincing answer to the question of why humans are flawed. But Jacobs says that this doctrine, this answer to a question that all thoughtful people must at one time ask themselves, has aroused more hostility than any other tenet of the Christian faith.

Even many Christians have seen original sin as dreadful or unbelievable. As one 18th-century preacher, John Taylor of Norwich, declaimed: “What a God must he be, who can curse his innocent creatures before they have a being! Is this thy God, O Christian?”

But other Christians, men and women from Augustine to Jonathan Edwards to Billy Graham, have held that original sin is not only a true picture of the way things are, but absolutely essential to understanding the human race. Jacobs quotes Blaise Pascal on this point: “Certainly nothing offends us more rudely than this doctrine [of original sin], and yet without this mystery, the most incomprehensible of all, we are incomprehensible to ourselves.”

Alan Jacobs’ book winsomely traces the doctrine of original sin from its source in the Bible through all its cultural permutations even to the present day: its arguments and counterarguments, and the luminaries throughout history who have fought so vigorously for it or against it. It is not a theological treatise and does not contain any long explication of the doctrine itself. Instead it is a history of how the doctrine, and its adherents and opponents, have influenced human culture in profound and lasting ways.

St. Augustine and the theologians he influenced have put forward the strongest and most lasting formulation of the doctrine. As he puts it, “Even infants are born sinners, not by their own act but because of their origin.” They are spiritually and physically descended from Adam and share in his peccatum originale. Augustine here is echoing Paul in Romans 5:12: “Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned.”

But it is not this simple for Christians. As Jacobs says early in the book, “We struggle to hold together a model of human sinfulness that is universal rather than local, in which we inherit sin rather than choose it, and in which, nevertheless, we are fully, terrifyingly responsible for our condition.” Our will is bound, as Luther would put it, but we are culpable for our sin. 

It is not only Christians who have come to the conclusion, at one point or another, that man was fatally flawed. The Greeks envisioned this flaw as a curse of the capricious gods, which could to some extent be excised by the pursuit of philosophy and the good life. Later civilizations had similar ideas. But in the 18th and 19th centuries, philosophers such as Rousseau, especially in his Emile, turned the opinion of intellectuals against any type of inherent flaw in mankind. In the proper environment and with the proper upbringing, Rousseau posited that a child (the titular Emile) could throw off the shackles of what an older generation had called sin.

The Catholic writer George Bernanos said that it was dangerous for men to deny original sin, and the bloody history of 20th century dictators who believed in the perfectibility of man, whether by culling non-Aryans or inculcating communism in the populace, is a sobering reminder of this fact.

But it’s not enough just to believe in original sin. For Christians, original sin is our state in this world, but it does not have to be the end of our story. The sacrifice of Christ paid the debt we owed, and the gift of the Holy Spirit makes it possible for us to live in a different way: glorifying God, and not ourselves; repenting our own sin, forgiving sin in others. We must ask unde hoc malum to understand our nature. We must ask unde haec bonitas to understand the free gift we have in Christ.

Original sin is not the end of the story, but it is the beginning. Alan Jacobs’ Original Sin: A Cultural History is an unmissable portrait of this doctrine through the ages.