Possible Implications of the Pope’s Words
One of the interesting possibilities that I think could be discussed comes out of Pope Benedict XVI’s treatment of this situation. He points out that mere ingenuity (tool use, control of fire, etc) is not clear evidence of the products of human rationality and souls. Intimate relationship with God would be.
Place this in the context of what archaeological evidence we have in pre-history, and even the artifacts dated earlier than 40,000 years do not necessarily show evidence of the work of Adam’s children. Those may have been produced by clever animals (this would, of course, also mean that the human-like remains beside them would not have belonged to Adam’s children; they would not have been people with souls). In this, our Pope is saying that appearances aren’t everything. The appearance of human ingenuity is not sufficient to prove human ingenuity. The appearance of human physical form (in the skeletal remains we have, for instance) is not sufficient to prove that that creature, back in that point in time, was indeed a child of Adam with a human soul.
Co-Existence
It also admits the possibility, as Grannymh concurred, that man could have lived alongside some of these other creatures (which I would identify with the scientific classification of “hominids”).
We still have certain other issues to determine, like evidence of descent of living humans (which Cornbread pointed out with the aborigines of Australia). And there are many possibilities there, as well.
For instance, it could be that Adam and Eve did live only 20,000, 15,000, 10,000, or even only 6,000 years ago. For that to be true, their descendants would have had to replace the extant populations apparently present in all regions of the world in relatively short order (though even 1,000 years is truly a very long time in human history). This might be plausible even by currently-known data.
MRCA and the Identical Ancestors Point
Even more plausible with current data might be some possibility of interbreeding (as in the Nephelim story). There is some very interesting work defining concepts such as “Most Recent Common Ancestor” (MRCA) and the “Identical Ancestors” point, both of which can be arrived at either by mathematical demonstration (the most common use) and by genetic demonstration.
The commonly accepted MRCA points out that all humans living today may share a single common ancestor who lived only 1-2,000 years ago (and, possibly, even closer in time than that!). The IA point is a little farther back, stating that after some point (commonly positioned between 5-15,000 years ago) in our past, ALL living humans share in common the overall set of ALL ancestors living beyond that time period. It gets a little complicated, but it has to do with human reproduction rates and gene flow. There are things that influence these, like regional and social isolation.
The “Leaven of Man” or “We are all Nephelim” Theory
However, these data can actually show that, if interbreeding were allowed for, a few thousand years after Adam and Eve, ALL living people would share common descent from them. So at any time point that Adam and Eve lived, if you allowed for interbreeding on a sort of “Nephelim” principle (“sons of Heaven” and “daughters of man” being not of the same status), within a few thousand years, all living descendants of the (scientific, biological) species would be share Adam and Eve as their ancestors, having been awakened with a spiritual soul by God because they are children of Adam and Eve. With the interbreeding portion as the key, I call this approach the “Leaven of Man” or “We are all Nephelim” theory
Most Likely Possibility?
I realize that will seem distasteful to some. I myself am more in favor of seeing the pre-historic data line up to show that Adam and Eve lived 40-70,000 years ago and their children spread from Central Africa to the rest of the world in a sudden blossoming of language and civilization (“behavioral modernity”). In so doing, they likely encountered other extant creatures (whom scientists may classify as homo sapiens or homo whatever), but eventually those others went extinct (with or without any interbreeding).
Therefore, I tend to look at what happened from 40YBP and onward with keen interest, to see what was going on during the lives of our ancestors