Maddenation
Abraham’s Descendents Explained
Always be a little skeptical when you see a title like that. In this case, be doubly so.
As we all know, Abraham was told by God that his descendents would be as numerous as the stars. Or something like that. Anyway, that’s a lot of people, even before Carl “Billions and billions” Sagan. The reason I bring this up is that Patrick, while writing an essay about counting things, mentioned that he was intrigued by the possibility God was wrong. Or something like that. But the question is nonetheless begged, just how many descendents did Abraham have?
After talking with Patrick, I decided (I don’t really decide these things. I just get hooked and can’t help it.) to investigate. My method of investigating is usually to think about it and do a little math. Never mind that somebody else has probably already done it better. I want to see for myself.
So, as I was falling asleep that other night when I confused myself with the population paradox, I also convinced myself that virtually all of us are descendents of Abraham. Surprised? Here’s my rationale.
First a simple thought experiment. Say there are only 100 people in the world and Abraham is one of them. He and Sarah get married and 100 years later they have their first child. Or something like that. Let’s make it simpler. Let’s say every couple has 2 kids to replace themselves, and that goes on forever. At the start, Abraham is 1% of the population. The next generation, he and Sarah have 2 kids, and the other 49 couples have 98 kids for a total of 100 kids. Now Abraham’s kids are 2% of the population. His kids get married (one has to assume precisely 50 boys and 50 girls, all marriageable for this to work) and have 4 kids. Now they’re 4% of the population. Within 7 generations, all the children are descendents of Abraham. (Sure, there may be some surviving “gentile” parents, but they’ll die off eventually.)
What if everybody has 3 kids and the population increases exponentially? Same answer. What if Abraham’s descendents don’t have as many kids as everybody else? First of all, do you really believe that? Families of 12 or more are recorded routinely in the Bible. That notwithstanding, if Abraham’s progeny have fewer kids on average, then of course they will not take over the population as rapidly, but it will still happen. I have the calcs to prove it.
What if you take into account that, after a couple generations Abraham’s descendents will be marrying each other? This will also slow the takeover, but it still happens in 10 generations or so. In fact, even if Abraham starts out as 1 in a million, his children take over in less than 25 generations. For each factor of 10 in original population, it takes only an additional 3-4 generations for the takeover. Amazing, but true.
What about the mountains and oceans and deserts that separate people, preventing them from meeting up and procreating? Don’t you believe love conquers all? OK, you’ve got a point. Obviously the very existence of different races strongly indicates that intermarriage was prevented by geography and distance. But even in biblical times, people traveled around and probably met lots of “outsiders.” And the Chinese and North and South Americans had to get there somehow. And, if we believe evolutionary biologists, it all started in Africa. So it’s possible, maybe likely, that some of Abraham’s children would have traveled far and wide. They were nomads, right? Wherever they went, they would have spread their genes very rapidly in the early generations. As they moved around the world, the probability of marrying outside the “family” would be high, and they would have reached a relatively high concentration in a handful of generations.
It would undoubtedly take a very long time for “abrahamees” to reach, say, China, or the new world. But Abraham lived perhaps 200 generations ago! And his children, the Jews, have been notoriously spread across the world. And the first ones to reach the new land would rapidly increase the “family.” (This is also true of any other family that has equivalent fertility. I’m making a case for complete mixing of the gene pool.) And remember, we’re counting anyone who has any abrahamee in their genealogy, even 100 generations removed.
It seems clear to me that it’s highly likely that most of us have Abraham in our genes. We also have the genes of most of the other people living in his day. Can’t we all just love one another?
Dad • Explanations • 04/16/06 • 0 comments
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