The June/July 2010 issuse of Free Inquiry has an article by a Christopher diCarlo titled "We Are All African." Unfortunately, the issue does not seem to be up yet on the Free Inquiry website, so I cannot link to the article itself.
The main thrust of diCarlo's article is that the common African ancestry of all humanity can serve as a means of promoting human unity today. Since "we are all African," he writes repeatedly, "we are all humbled," "we are equal," "We are all exactly the same."
That's all well and good, of course, though I have my doubts that it really gets us anywhere.
The problem I have with the article though is where diCarlo references a book by a Steve Olsen titled Mapping Human History. According to diCarlo, "Olsen has calculated that we have to go back in time only 2,000 to 5,000 years to find someone who could count every person on Earth today as a direct descendant. If we go back just a little further, 5,000 to 7,000 years, every person is a direct ancestor to the over 6 billion people alive today (unless their line of descendancy died out)."
Now maybe I am overlooking something, but I just don't see how this is possible. If the ancestors of the Australian aborigines arrived in Australia some 40,000 years ago or the ancestors of Native Americans reached the Americas some 12,000 years ago, then how can a person who lived in Egypt some 5,000 to 7,000 years ago be the ancestor of all humanity? Since anatomically modern humans first began to migrate out of Africa some 60,000 years ago, it would seem to me that the ancestor of all modern humans would have to have lived more than 60,000 years ago. If anyone reading this could shed some light on this paradox, please feel free to enlighten me.
While I agree with diCarlo's sentiments about promoting a common humanity as a means of overcoming racism and xenophobia, I can't help but think that some humans left Africa some 60,000 years ago because they were either forced out or they were trying to get away from other people with whom they did not get along with very well.