Ancestral considerations

I neither am particularly concerned nor do I care to know who my ancestors were. I think that information is only of mild anecdotal interest, like "this is where Pickett's charge took place": cute if you are touring Gettysburg, but not essential to the knowledge of history. Even if I had some more information about my ancestors than I do, and if most of it beyond two or three generations was not utterly lost among the ashes of the Holocaust, I would be neither particularly proud to have "good" ancestors nor particularly ashamed to have "bad" ones. As it happens and will be seen later, all of us in all likelihood have both.

But though the questions of WHO don�t motivate me, the questions of HOW MANY seem to lead to some startling conclusions. Please let me know of any errors you find in my reasoning.

The length of a generation is usually acknowledged to be between 25 and 30 years, i.e., three or four generations per century. The exact figure we choose does not change the results substantially. And let us keep into account that throughout most of history the length of a generation was much less, because people of 25 or 30 years were already old and most often bred at much earlier ages. Let us count four generations per century.

Let us take eighteen hundred years ago as an arbitrary date for computation: we are in 202 C.E., during the empire of Septimius Severus, 1800/25=72 generations ago.

Since all of us have two parents, four grandparents, eight great-grandparents, sixteen great-great-grandparents and the number of our ancestors doubles with each generation, the number of our ancestors 72 generations ago was
2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*
*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*
*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2=
=2^72=4,722,366,482,869,650,000,000.

This is 787,061,080,478.274 (roughly seven hundred and eighty seven billion) times the current world population estimated at six billion.

Even if the world population had been 6 billion during the entire time human beings have been on this planet, the total number of human beings EVER would be much less than 4,722,366,482,869,650,000,000.

This leads me to the following conclusions: all of us have many ancestors in common; many of those ancestors in turn must have had the same ancestors, many of whom had the same ancestors, many of whom had the same ancestors, many of whom had the same ancestors...

We are all so mixed that ALL racial distinctions are utterly meaningless, like the presence or absence of a mole or eye color.

Does this mean that Adolph Hitler and I have some of the same ancestors? Alas, yes, though far enough in the past to be shrouded in the mists of antiquity... And besides I DID start out saying I would be neither proud nor ashamed of my ancestors, didn�t I?...

Besides in my opinion the sharing of memes counts for much more than the sharing of genes. That is why I prefer my friends to my relatives, and I AM proud of my memetic ancestors, whom I have chosen, unlike my genetic ones, whom I have not.