Antoine and Al,
This is my relational take on the First Sin. It revolves around faith as found in Paul's writings.
Before the Fall Adam and Eve has faith in God in that they did not eat from the Tree, however this faith was in a sense passive, because it was not tested. When it was tested by the words of the serpent, who of course represent Satan, the Accuser, their faith gave way and the trusted the words of the serpent, rather than the Word of God.
The story in Gen 3 represents real events, but it presented in such away that reveals the spiritual and psychological realities behind these events. The truth of the event/story is based primarily in the truth of these spiritual and psychological realities.
As indicated above, initially the First Humans (humans in terms of mind and spirit, not just genetically) were in harmony or right relationship with God (YHWH.) In this they were like God's other creatures, but YHWH gave them one directive to guide their actions, not to eat from the Tree of Knowledge of Good and Evil. They accepted this so they did know rationally the difference between Good and Evil, but since there was no sin, they did not know evil existentially.
When they moved from faith to distrust of God, and ate of the Fruit, they knew sin existentially. and felt shame and fear. They became separated from God and each other. Fear begets fear and they refused to acknowledge their responsibility for their sin and blamed others and indirectly YHWH. Through their estrangement from God they became estranged from nature, etc.
Humans are cr4eated in the Image of God, which makes it possible for us to sin and may be inevitable, but it is the same things that make it possible for humans to sin, that make it possible for them to be saved. They are relational beings, created in the Image of God as body, mind, and spirit, complex/one being who can recognize our sin, understand our need to change, and throw ourselves at the mercy of God. We cannot save ourselves, but we can be saved by the grace of God through faith.