Central to nearly every branch of Christianity is the notion of original sin – the belief that humans in some sense start out corrupted, that sinfulness is our default state. The apostle Paul expresses this idea in verses like these from Romans:
“Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned… Therefore as by the offence of one judgment came upon all men to condemnation.” (5:12,18)
Among Christian fundamentalists, original sin usually finds expression in the belief that Adam, the first human, was the “federal head” of the human race, such that the effect of his sin was inherited by all his descendants. But even in denominations that don’t take Genesis so literally, belief in original sin is common, though they believe we came by it somewhat differently.
But regardless of the underlying interpretation, the most serious logical flaw in the doctrine is this: Why is it that this taint of badness affects the entire human race?
Neither the liberal nor the conservative interpretations of Christianity have a good answer to this. Many liberal theologians consider the source of original sin to be an event that occurred sometime in humanity’s past, such as C.S. Lewis:
We do not know how many of these creatures God made, nor how long they continued in the Paradisal state. But sooner or later they fell. Someone or something whispered that they could become as gods…
But since Lewis regards the fall as a particularly individual sin, he’s left with the unanswered question of how it came to affect every single human being. Shouldn’t there have been some people who made the right choice? If humanity was made such that everyone fell prey to this sin, we may well question whether the decision to do so was free at all, or if it was the inexorable result of something God built into our character. A defect in one or a few products may occur by chance, but an identical defect in every single product suggests a design flaw on the part of the manufacturer.
The conservative view, meanwhile, fails to explain why it is that Adam and Eve’s sin, however heinous it was, came to pollute not just them but all their descendants. Tortured apologetics about how we all sinned “in” Adam cannot change the simple facts that we did not exist, we were not there, and we certainly had no part in the decision. Why didn’t Adam’s children start out in the same state of unspoiled innocence as their forebears originally enjoyed? Why did his sin change our character? If the laws of inheritance work this way, there’s only one person who could have set them up as such – and again, the conclusion is unavoidable that God intentionally arranged things so that the curse of sin would spread to the entire human race.
But according to Christianity, this is not what God chose to do. Instead, he deliberately introduces a taint of sin into the entire human race, blames us for that flaw which he himself gave to us, and then puts his own son through horrendous suffering in an attempt to fix it; an attempt which mostly fails, as he knew in advance that it would, and results in the majority of people being eternally condemned. This is either sheer insanity or deliberate malevolence.