Jefferson M Fish Ph.D.

Looking in the Cultural Mirror

Another Reason Races Don’t Exist

What powers of two and human population growth tell us about race.

Posted Aug 08, 2011

Population growth [1750-2000]

The human species has no races in the biological sense--all that exists is gradual variation in what people look like, with more distant populations appearing more different from one another than closer ones. "Biological race," in contrast to the social concept, is not one that applies to modern humans--even the question as to whether Neanderthals were a different race (i.e., subspecies) or a different species from our ancestors has not yet been definitively resolved. For this reason, only a few of my posts (1, 2, 3, 4) have dealt with biological issues related to race.

Here is one more reason that the human species has no races--this time using logic, the powers of two, and the facts about human population growth.

Exponential growth—the green curve shows how continual doubling rapidly surpasses linear and cubic growth.

Before modern medicine and public health, people didn't live very long and reproduced when they were young. To be conservative, however, let's count 25 years per generation. 40 x 25 = 1,000, so that means that a thousand years ago, every human alive today has over a trillion ancestors. However, modern humans have been around for about 200,000 years, so it is easy to see that--adding another three zeros every ten generations, or 250 years--this accounting gives us more human ancestors than there are atoms in the universe.

There is another problem, however--the facts go in the opposite direction from the math. While the calculation of ancestors gives us numbers that explode in magnitude the further back in time we go, the actual history of the human species has been just the opposite. That is, we are actually undergoing exponential growth in the size of the human population, so that the further back in time you go, the smaller the number of humans. (See the first figure showing the world's population more than doubling during the second half of the 20th century.)

How can we reconcile this contradiction?

There is one clear answer. They are all the same people!

That is, your biological great-great-great-great-etc. grandparents and my great-great-great-great-etc. grandparents, and for that matter the great-great-great-great-etc. grandparents of everyone on the planet are the same people. Whatever the superficial differences in what we look like, in biological terms we are all closely related--too closely related for the human species to have races.

Image sources:
Population growth [1750-2000]

Exponential growth--the green curve shows how continual doubling rapidly surpasses linear and cubic growth.
Comparison between

Check out my most recent book, The Myth of Race, which debunks common misconceptions, as well as my other books at

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