For Eriugena, humans are a microcosm, a miniature of the entire cosmos. The fall of Adam is not just the fall of a person, but a cosmic event. The Fall is regarded as a deviation from the ideal Man -- and of course, this ideal is in the mind of God. The real Man, therefore, is an intellectual notion in the mind of God. And what is this idea in God's mind? The essence, or definition of Man: a rational animal. Notice that this definition is not gendered. The division of sexes is a consequence of the Fall. At the end of the world, the distinctions between sexes will vanish. (More heresy charges).
Now, the fall has given us the likeness of animals, which is far away from true rationality. We fall to the brink of total annihilation. At the very extreme point of the fall, we begin the return. There are five stages to this return:
1. First, the body is resolved into the four elements. This is death, and the corruption of the body.
2. Second, there is the general resurrection at the end of the world, where we all get our bodies back. This sounds like more regression, but it isn't.
3. Third, this glorified, resurrected body is transformed into spirit.
4. Spirit then becomes absorbed into the primordial causes. That is, we return to the divine ideas from which we came.
5. All nature and the primordial causes are reabsorbed into God.