Original Sin: an explanation for those who don't believe all that "God" stuff
First I should explain the word theism. "Theism" is the error of confusing metaphors for God with the real thing: confusing the signifier with the thing signified. To a certain extent, theism is an unavoidable error in talking about God since God is ultimately ineffable. God is infinite and our language is finite.
Just because something is infinite, however, does not mean it is unknowable or nonexistent. A few examples from elementary geometry should suffice to clear this up. Geometry uses as pure axioms a number of infinite concepts: the "line" , the "plane" and the "point". A line (as opposed to line segment) is both infinitely long and infinitely divisible. We draw line segments on a black board or printed page to signify a line (sometimes with little arrows on the end to remind us that it is supposed to represent a line, not a line segment). Similarly, a "point" properly understood is not the smudge on the blackboard we use to indicate the location of the point. As Euclid defined it, a point is that which has no part. See Euclid's Elements: Book I, Definition 1. Obviously, in order to be visible, the smudge on the blackboard or bold dot on the printed page has to have "parts" (be divisible) and therefore isn't really a point.
In geometry, confusing the sign with the thing signified can lead us into errors. When we draw two parallel line segments, it seems intuitively obvious that if the segments are extended infinitely in both directions, the two line segments never meet. Assuming this to be true, as Euclid does in Euclid's Elements: Book I, Postulate 5, gives us one kind of geometry (which we call Euclidean). Assuming it to be false, however, gives us another kind of geometry, Non-Euclidean geometry. Non-Euclidean geometry is not only interesting but has some useful applications, such as Einstein's adoption of Riemann's geometry of a positively curved, finite and unbounded space to describe gravity.
Some of the errors of theism are as obvious as confusing a smudge with a point or a line segment with a line. Those include all anthropocentric descriptions of God. Obviously, Michelangelo's paintings of God in the Sistine Chapel, as a white-haired old man wearing a diaphanous white shirt which covers but still reveals his fat ass, are not accurate pictures of God. While these decorations may be beautiful and reveal some truths about God, in truth, God is not old, male, or subject to buggery, no matter how lovingly Michelangelo painted his butt.
Other errors of theism are more subtle, as subtle as Euclid's choice of uncurved space in Postulate 5. Generally, they involve drawing unwarranted conclusions from anthropocentric metaphors for God. These metaphors include talk about God as if God has human emotions, desires, and intentions, talk about "God's wrath" or "God's love". While these metaphors have literary value and can convey something meaningful and true (I am particularly fond of the metaphors of love and forgiveness) they can lead us into error, or poor "choices" (the meaning of heresy in Greek).
The Doctrine of Original Sin
The doctrine of Original Sin is an exegesis or rational interpretation of the Genesis story of Adam and Eve and the Fall of Man in the third chapter of the Book of Genesis. It begins with a conversation between the first woman (as yet unnamed) and a "crafty" serpent, about the fruit of a certain tree in the Garden of Eden. God had prohibited the man and the woman from eating the fruit of the tree. The serpent told the woman that she would not die if she touched the fruit, but rather "when you eat of it your eyes will be opened, and you will be like God, knowing good and evil." Genesis 3:5. Initially, the only effect was that they realized they were naked and felt ashamed. Then they "heard the sound of the LORD God walking in the garden at the time of the evening breeze" and hid from him. Genesis 3:8. God, apparently unaware of what has transpired, calls them out and demands an explanation. The man blames it on the woman, and the woman blames it on the serpent, and God curses them all. They are no longer immortal, they have to work for a living, and they are driven out of the Garden. God also declares that the man shall rule over the woman. Genesis 3:16. Then the man names the woman "Eve" "because she was the mother of all living". Genesis 3:20.
This story is broadly mythological and can be interpreted in a number of ways. It is rife with mind-breaking questions, for example: did God lie when he told the man and the woman that they would die if they touched the fruit, or did God already know he was going to take immortality away from them when they disobeyed him? If so, why go through the trouble of telling them not to? (This is the question of free will).
Late Jewish apocalyptic writings attributed the world's corruption to the fall of Satan or Lucifer. In this story, brought vividly to the English-speaking world by John Milton in his epic poem, Paradise Lost, the serpent's motives in deceiving Eve can be traced back to a revolution in Heaven, and a prior casting-out by God: the Fall of Lucifer and his accomplices in treason. The other religions founded on the Genesis story, however, Judaism and Islam, don't subscribe to the doctrine of Original Sin.
The doctrine of Original Sin is mired in some of the worst aspects of Christianity; which include a primitive, irrational theism, misogyny, and a sick revulsion for our sensual, physical selves, and in particular, our sexuality. The peculiarly Christian (and peculiarly ugly) interpretation of the