In 1921, Raymond Pearl, Professor of Biometry and Vital Statistics at Johns Hopkins made a starting prediction that the upper-limit of population which could be sustained by the United States would be reached in 2060 and that it would be around 200 million souls. Dr. Pearl employed logically-sound analyses extrapolating from the Malthusian doctrine prevalent at the time, as well as state-of-the-art calculations of growth-curves for other nations and other animal populations such as fruit flies. Of course, his calculations were wildly off: in 2011, the United States reached a population of over 310 million.
In October of the same year, according to some analysts, the world’s human population surpassed a statistical 7 billion. Of course, no one really knows when that demographic milestone was reached and the selection of the 7 billionth infant in 2011 was largely a symbolic act. Regardless, the world’s population is in the midst of an explosion with no immediate signs of stabilizing.
Although there is no way for knowing for sure, it is estimated that the population of the world surpassed one billion in the early 1800s. To double to two billion it took over 100 years, but reached three billion in only thirty or forty more years. By most official estimates, the global population exceeded four billion the year I was born, five billion when I was in the sixth grade, and six billion by the time I got my master’s degree. Given these trends, I do not think I will need to live very long to see it double in my own lifetime.
Since the mid-Seventies, Carl Laub of the Population Reference Bureau has attempted an audacious exercise. Laub has been trying to reach an estimate of the number of humans that have ever lived, starting from a statistical first couple at 50,000 B.C. In mid-2011, he arrived at approximately 108 billion humans (give or take a few billion). His analysis presumably does not take into account an evolutionary bottleneck caused by a supervolcano which erupted around 70,000 B.C. causing only a few thousand of our ancestors to survive, but otherwise seems plausible. It is in the ballpark.
If that is indeed the case, 108 billion is the total sum of every man, woman, and child that has ever lived. This number included every Buddha, Aristotle, Alexander, Genghis, Shakespeare, Kalidas, Hitler, Da Vinci, Stalin, Lincoln and Newton. It also includes the vast multitudes of humanity who, for better or worse, never reached their true potential in life and thus, disappeared into the quicksand of obscurity.
But even the people we have memories of lived very recently. As Carl Sagan astutely noted, if you put the cosmic scale on the Gregorian calendar, all of human existence would pass by on the last ten seconds of December 31. Even if we stretch this timeframe to include only the time humans have been on the planet, there is no existing narrative for most of our existence. The oral, mythical traditions of our preliterate ancestors –and the written word is a very recent construct even for those fortunate to have access to it in modern times – have mostly vanished. For 99.9% of human existence, our ancestors were hunter-gatherers. How long did they live? What did they die from? We will never really know. Our ancestors are alien to us.
No wonder the challenge in explaining the remaining recent 0.01% puts the social sciences on unenviable ground. At best, history and sociology can provide fragmentary papyruses on the few individuals, customs, and events which have influenced us the most. At worst, as conflicting accounts of the tragedies at Nanking and Dhaka in recent times show, oppressor and “oppressee” will obfuscate any approach towards an absolute truth, so that it is unknowable even for the most detached of observers.
The physical and life sciences cannot bring an absolute framework of knowledge to pass either. For example, biologists cannot study (or possibly even identify every living organism) that was or is alive on this planet. A few model organisms, such as E. coli, yeast, worms, and fruit flies are studied in extensive details to make associative inferences, and we will continue to know more, but scientific knowledge will always be fragmentary too.
If scratching beyond the surface of the duration of human existence is impossible, if absolute knowledge is a mirage, it does not diminish the value of knowing what is knowable. As Thomas Kuhn hypothesized, it is the relatively short spurts in which revolutions and paradigm shifts occurred that human history was likely shaped.
I am inclined to take the democratic view that human culture is the sum of what is important to all humans. If that is so, then our modern times, hold special significance. Over 6% of every human who ever breathed on this earth is alive now. (On a sobering note, this also means that over 6% will die in a lifetime: an unprecedented scale of deaths the likes of which have never been seen).
In absolute terms, this puts immense pressure on society. Languages, for example, are under extreme duress to conform to the needs of an unprecedented number of users in extraordinary situations.
For the most of human existence, apart from just after wars, pandemics, and famines, the present has been the most important time in history. And if today is the most important day ever for humanity, then it behooves us to ensure we do whatever is possible to improve the collective human condition.