We now come to the story of the Nephilim at the beginning of Genesis 6, when the "sons of God" associated with the "daughters of humans". These Nephilim passages are famously difficult to interpret, and there is no one obviously correct explanation among the usual candidates. But my theory offers this interpretation:
The "sons of God" were the descendants of Adam and Eve, fully spiritual humans bearing the image of God. Most of the "humans" to whom daughters were born were merely biological humans, who would have significantly outnumbered the descendants of Adam and Eve at this time. As the population of both the spiritual and biological humans increased, they started interacting with increasing frequency. Marriages between them were very common, and there was nothing wrong with that, as it was a part of God's plan to make Adam and Eve ancestors to all of humanity.
Now, as I previously mentioned, the descendants of Adam an Eve enjoyed many mundane, material advantages that flowed down from their spiritual identity. They would have been wealthy, powerful, and respected among the merely biological humans. And as powerful, fallen men have done throughout history, they indiscriminately slept with any beautiful women they wanted. It was easy for them to take these women from among the relatively weaker biological humans. These unions then produced children. Now, this was not according to God's plan: remember that in my model, the image of God is propagated through spiritually formative relationships, such as fatherhood. But these men, who slept with any women who caught their fancy, would have made terrible husbands and fathers. Many of their children would have then grown up with the warped spirit that comes from having a bad father. As this process repeated itself over several generations, the people born and raised in this wicked way multiplied. Eventually, their wickedness would bring about God's judging flood.
But not everyone conformed to this pattern. There were still exceptions. So, on rare occasions there would still be a son of Adam and Eve who married a biologically human woman and loved her properly. The children born from their union would have been raised right, and so they would have enjoyed all the advantages that their father passed on to them. If these children then lived among the merely biological humans, they would have been considered exceptional individuals. As fully spiritual humans who also possessed many mundane, material advantages, they would've been capable of remarkable feats. These were the Nephilim: heroes of old and men of renown, as they would have been known among the biological humans.
Now, of course I can't be certain of all this. The fact is that the Bible simply doesn't give us enough information in this short passage at the beginning of Genesis 6. This is a problem for any interpretation of this passage. However, my interpretation has the advantage that it flows quite naturally from its basic assumptions: Given that fully spiritual but fallen humans lived alongside merely biological humans, this is what you'd expect to happen. It also has the advantage that the elements of the story do not pop out of nowhere: in my model, "sons of God" and daughters of "humans" were present from the very beginning, and the interaction between these groups were mentioned in the earlier parts of Genesis, as I described in the previous post.
That now brings us to Noah's flood. Interpreting the flood with the full treatment it deserves would take another several posts, and I would mostly be repeating what others have already said. But for the sake of completeness, I will briefly mention that my model requires the flood to be localized, and that I trust the expertise of others when they say that a local flood fits with the language of the biblical text.
Now, I don't know Hebrew, so I'm not qualified to judge these statements by experts. But I can say that a local flood agrees well with the established principles of Bible interpretation: it makes no sense to interpret the flood with the modern meaning of "globally", when the original author and audience were not aware of the globe of the Earth. The animals also make more sense in a local flood: if you were to apply the modern taxonomical definition of 'every animal', and the modern definition of 'the whole Earth', it is simply impossible that all the animals fit in Noah's ark. Of course, reading the text this way is a pretty blatant violation of the rules of Bible interpretation: you're completely taking these words out of their ancient context and reading into them our modern meaning. If you instead interpret the story as the original author, audience, and characters would have understood them, then everything fits: the flood was local. The animals were only the types that were endemic to the region, as classified by one family with an ancient understanding of biology. So penguins and koalas were not on the ark. Probably no tigers, giraffes, moose, or elephants either. And all types of rats, mice, and squirrels might have been classified as one kind of animal. The ark was sufficiently large in this case, and it needn't be responsible for the biodiversity of the whole planet.
After the flood narrative, there is the story of the tower of Babel, in which God scatters the people over the face of the earth. In my model, this is one of the events that allows Adam and Eve be become the ancestor of humanity much more quickly than would otherwise be expected. Also, note that these people would have been scattered into areas which would have already been populated with biological humans. This explains a curious feature of the flood narrative - that there are similar, but not identical, flood myths found all over the world. As the descendants of Noah spread out after Babel, they would have carried with them the story of the flood. It would have been the most catastrophic, dramatic, and morally important event in these people's history. But as they then mixed with the locals in their new area, the story would have been distorted and sometimes forgotten: if all four of your grandparents tell you the same flood story about how the world was nearly destroyed, you'd be sure to tell it to your children in the same way, as part of the oral history of your people. But if only one of your grandparents, who used to live in a different part of the world, told you the flood story, it's much more likely to be distorted, mythologized, or forgotten - and this is the way we find the story today.
As for the passages outside of Genesis, my model is in harmony with all of them. There are many passages which briefly describes how God created the world (Jeremiah 10:12, Isaiah 45:18, Hebrews 11:3, etc.), all of which my model affirms. My model also agrees with Acts 17:26 that he created every nation from one origin, as we're all descendants of Adam and Eve. My model furthermore agrees with all the verses that use creation order arguments to discuss doctrinal matters, such as Matthew 19:4, Mark 10:6, 1 Timothy 2:13-14, and 1 Corinthians 11:8-9. With a historic Adam and Eve, along with generic humans being created as male and female during the sixth "day" in the Genesis prologue, my model fits all these verses. Additionally my model is in harmony with verses which talk about the flood (1 Peter 3:20, 2 Peter 3:5-6), as a historical event through which some humans were saved. And, because my model is compatible with mainstream science, it is also in harmony with all the verse that describe science.
Lastly, my model is in perfect harmony with the important verses that describe our salvation, 1 Corinthians 15:22 and Romans 5:12-21. My model affirms a historical Adam, who became the ancestor to all humans, whose sin therefore infects all humanity, which results in spiritual death.
So, there are many verses that are explained best by my model, while there are no verses which give my model any exceptional difficulty. All this, combined with the biblical texts that I have discussed at length elsewhere in this article series, means that my model is in excellent agreement with the whole of Scripture. In fact I believe it to be the most biblical model among its rivals - otherwise I would not believe it.
As I said previously, there are people in my personal life whom I respect - many who are more knowledgeable and more godly than I - who hold to a different model for the Genesis creation story. I respect their views and the other ways of interpreting Genesis. I am therefore still open to modifying my thinking - pending better exegesis, clearer interpretations, better understanding of the original language, and a better historical and cultural understanding of the biblical authors and audience. But with the best evidence I have now, with the best understanding of the Bible I can currently attain, and having done my due diligence, I believe that my model, among its rivals, is the closest to the truth.
You may next want to read:
The biblical timeline of the universe (Next post of this series)
Interpreting the Genesis creation story: an introduction
Common arguments about the creation account (Part 1)
Another post, from the table of contents