The first problem is that if Cain is the third human and he kills the fourth human (Abel - Gen. 4:8), this would mean the only other humans on earth are Adam and Eve, and perhaps later some other sons or daughters that Adam and Eve might have given birth to in the meantime.
So why would Cain need to have a mark put on him by God, 'so that no one who found him would kill him'? (Gen. 4:15) Where did the others who might threaten Cain's life come from?
This problem is further evidenced when Cain lays down with his own wife (Gen. 4:17). Where did the wife come from? Did Adam and Eve give birth to a daughter? If so, why doesn't it say that Cain laid down with his sister? This would also mean that humanity is a product of incest, right?
The confirmation that this text is allegorical in context is the following verse:
Then the LORD said to Cain, "Where is your brother Abel?" (Gen. 4:9)
We know this event is allegorical because God knows everything. God doesn't have to ask Cain where Abel or anyone else is, just as God didn't have to wonder where Adam was when he and Eve were symbolically hiding in Eden. ("Where are you?" (Gen. 3:9)).
We also have Cain speaking with sarcastic disrespect to God, saying, "I don't know. Am I my brother's keeper?" (Gen. 4:9)
These points and many others indicate these verses are not historical events of the first humans on the planet earth.
The problems with these verses lies not with whether the facts in them are true or not: Rather, it is that they have been mistranslated and misinterpreted. Ecclesiastical (professional) scholars and clergy from the Christian and Hebrew religious organizations have created these problems because they did not understand the meaning of these verses. Rather, in an attempt to create credibility for their respective religious groups, they have attempted to create a false historical chronology with these verses.
This doesn't mean that these verses are not factual or historical. Rather, they are simply misunderstood and mistranslated.
The fact is, the speculative interpretations of these verses have no credibility. For example, scholars have established that if this interpretation of these texts is true, humans could only have lived on the planet for about 5,000 years. This creates a real credibility gap, because archaeological evidence has traced humans on the planet back hundreds of thousands of years, and the ancestors of humans back millions of years.
And while the precise time measurement of their history - requiring carbon dating - may have some minor calculation error (most agree 5-25% margin of error), there is no doubt that the time span of humanity is far longer than this false historical lineage portends.
Ecclesiastical Christianity and Judaism are thus faced with two choices: Maintain their stance that archaeological evidence is all in error and this is an accurate genealogy of humanity; or consider another interpretation of these texts that can embrace the observation of science.
This is a big reach for the fundamentalists, because if they embrace science, they will need to be open to the possibility of evolution - something they have been opposed to. The idea that humanity developed progressively over time through the species is diametrically opposed to the concepts these texts supposedly communicate.
We say supposedly, because the interpretation and translation of these texts have been performed by those scholars and clergy that have already been indoctrinated into the supposition that Cain was the third human and this is how humankind developed. Thus the translation and interpretation of these texts are in fact a self-fulfilling prophecy. It is actually no worse than the archaeologist who interprets bone fragments with the preconceived notion that those bones he finds are from a first-born species of humanoid.
These kind of speculative assumptions are created in the mind. They have nothing to do with reality. The reality of the bone fragments is that this is one fragment found in one location among a gigantic earth full of other possible locations where more advanced humanoids could have existed at the same time or prior to that humanoid. Their bodies may not be found easily because they have been burnt by volcanic eruptions or burned in burials, for example.
The fact that archaeological speculation also has its limitations is proven by the fact that many recent dig findings have outdated previous findings that archaeologists have insisted were the oldest humanoids. By this fact alone we can understand that grandiose claims of finding the first human by archaeologists is just as prone to error as assuming that Cain is the third human - as both assumptions are based upon speculations from small minds drawing upon limited sense perception.
Getting beyond the speculation, these texts in Genesis: 1) have historical significance outside the scope of our sense of chronological earthly history; and 2) focus on specific events in order to impart particular lessons.
For example, if they were historical persons, there would be numerous other events that took place in the lives of Adam, Eve, Cain and Abel. Yet we find only a few isolated events. What kind of history of humanity would be so brief about the lives of the supposed first and second humans?
The fact is, this is not a history of humankind. The historical significance is being created by the translators and interpretors. The fact is, most of the "chapters" (actually sections, because some run together) of Genesis were separate scrolls, as each of the genealogies described is divided by what is called by Hebrew scholars a colophon.
A colophon is a separating element, signifying that the next text came from another scroll or manuscript. Most Hebrew scholars believe that there were at least 7 different scrolls that were patched together to form the book of Genesis.
This is also why we tend to see, should we read through all the chapters of Genesis, a jumping back and forth between people and events in terms of chronology.
These ancient scrolls were taken from ancient teachings that before they were recorded onto parchment or papyrus, were passed down from teacher to student(s) orally.
While some teach that Moses wrote Genesis, scholars now admit that different people wrote the original Hebrew scrolls, some of which were translated into Greek before being bound together as though they were one book called Genesis.
Then we must ask, what sort of genealogy is being described here? Were the original scrolls aimed at creating a chronological history of the Jewish religion? No. It was ecclesiastical clergy in the following centuries (such as those Jewish high priests and scholars that Jesus railed against) from the Jewish and Christian organized religions that sorted the various scrolls - whilst tossing out many - trying to piece them together as a historical chronology to make a case that their religious institution is the only legitimate one.
This is why these texts do not cover in the least, the long histories of other cultures, such as those of South America, India, China, Egypt and elsewhere.
Rather, the various scrolls that documented the oral teachings of the ancient teachers were recording significant events that took place concerning specific persons - sometimes symbolic persons as Adam and Eve - and sometimes historical persons.
This was the ancient method of teaching. A teacher may describe a particular event to convey a spiritual lesson to be derived from that event. Sometimes the events were symbolic. Sometimes they were historical. Jesus used both symbolic events (parables) along with historical events describing David, Samuel and others as he taught his disciples, for example.
As these various lessons were collected by ancient scholars, some rascals sought to organize them to achieve a purpose they were not originally intended to achieve. Thus we end up with a mix of patched-together teachings of particular events, together with a speculative attempt to tie them together by ecclesiastical scholars that sought to provide credibility for their respective organizations. This occurred amongst both the Jewish religions and the Christian religions at different times, effectively building upon each other.
Thus, while one can find historical relationships with God through the ages, the intent of the original scrolls was not to create a history of mankind. The intent was to teach us - through some key events - some historical and some symbolic - lessons on who we are and what our purpose in life should be.
In other words, the original lessons are still contained in these verses. God has made sure those lessons have been preserved, and that is what makes this scripture. Perceiving those lessons within the murkiness of the translations and interpretations may be difficult, but there is an ultimate purpose for this: It provides a veil or barrier for those who are not serious about returning home to God.
Remember that in the previous chapter, the symbolic Adam was tossed out of Eden, and a barrier was put between him and Eden so any return to Eden was physically impossible. This of course took place after Adam ate the symbolic fruit that God asked him not to eat. This barrier to returning to the spiritual realm has innumerable manifestations, including misinterpretations of scripture.
Now we find, after Adam's symbolic fall, that both Adam and Eve (actually "man and his living wife" from the Hebrew) are still cognizant of God, as God has been given credit for the birth of Cain.
However, within the text is a clear communication: The Hebrew word being translated to "Cain" literally means 'possession.' This is combined with the symbolic Eve's statement, "....I have brought forth a man..." of which "I have brought forth" is derived from the Hebrew word קנה (qanah), which literally means, 'to get, acquire, create, buy, possess,' according to the lexicon.
These two words in the verse confirm a deeper meaning than simply the first two humans giving birth to a third human. The verse indicates the beginning of the concept of possession: That we, after our fall from the spiritual realm, began to perceive our offspring and other elements of the physical world as our possessions.
This element of possession is the first phase in the progression of our continued downfall into the depths of the physical world.
Thus we find this event is symbolic, and the central players are also symbolic:
Adam symbolizes each of us individually.
Eve symbolizes us as a community.
Cain symbolizes our error of conceived possession within the physical world.
As is explained in chapter three of Genesis, we were cast out of the spiritual realm due to our envy of God (we wanted to be "like God" (Genesis 3:5). As we were thrown into the physical world, we were given "garments of skin" (Gen. 3:21) or these physical bodies. Then God placed a barrier between the physical world and the spiritual realm so we couldn't return whimsically.
Now we see the first event of our lives within the physical realm, as we begin to identify with these physical bodies, and feel that we "possess" our children and other material possessions. While we can see that Eve still gives credit to God for Cain, this concept of "possession" is what gradually leads to further acts of selfishness, as we'll see later in this chapter.
One of the central reasons the ecclesiastical (professional) translators and interpreters of these ancient teachings did not understand this concept is because they, too, were entrapped by the illusion of possession, thinking that they and their ecclesiastical organizations have some right of possession. So they attempted to rearrange the ancient scrolls in such a way as to suggest chronological history, in order to suggest their ecclesiastical religious organization offers the only means to being saved - as well as being the only rightful owners of the supposed "promised land."
This problem is specifically why the Israelites and the Arabs have been and are still to this day violently struggling with each other: Both sides are assuming that their religious institution has the right of possession of the lands they occupy or don't occupy around the Middle East.
The fact is, the Supreme Being owns everything. He owns all the land, all the mountains, deserts, oceans, forests, and every other material element. He owns all of the Middle East: Every spec of sand, every sand dune and every oasis.
We can know simply that we own nothing on this planet because ownership requires control. Each of our physical bodies will die and decompose, and we will leave them behind. With them, we will also leave behind whatever we thought we possessed. Because we will leave those possessions behind, we have no control over them. Thus we have no ownership.
Only God has ownership, because He has complete control over all the elements.
Therefore, it is ridiculous to fight over God's property.
This element, possession, provides a foundation for all the greed, violence and hatred that exists around the planet. We are thinking that we can own the stuff of this world, and what we don't possess, we want to, because we want to own it. This is rooted, again, in our envy of the Supreme Being. He is the rightful owner of everything, yet we want to own what He owns.
Understanding these two lessons: that we are not these physical bodies, and everything is owned and controlled by God, provides our first step in returning to our natural position in the spiritual realm as the Supreme Being's loving care-givers.