The article on the Stone Age on Wikipedia reads that the Stone Age “represents nearly 99.3% of human history.” Is this true?

If you measure human history as “the number of years for which humans have existed”, then the 99.3% figure is indeed true. Hominins began using stone tools ~3.3 to 3.4 million years ago, and the Stone Age gave way to the Bronze Age roughly 5,000 years ago (both ends are a bit wobbly and vary with the location studied, the definition used, and one’s views on the credibility of some specific archaeological findings).

A tangent on what “human” means:

  • The term “human history” will naturally carry a different meaning, depending on what you mean by “human”.
  • The notion of a species is actually very wobbly too - Darwin was aware of this, and undergraduate biology students today tend to think more in terms of clades. Even in vertebrate animals, where the concept of a “species” is most frequently useful, it is often difficult to draw precise lines that demarcate two species. This is especially true as you go back in time - it seems to have been surprisingly common for divergent hominin groups to meet and interbreed. What we call “Homo sapiens” today is actually a mix of a few different hominin “species”.
  • Some sensible places to draw the line of where “human history” begins could be ~3.3 million years ago (first reliable evidence of hominin tool use), or ~2.8 million years ago (earliest known specimen of Homo), or ~2.1 million years ago (first known emergence of Homo habilis, a group that has been placed by some scientists in the genus Homo - though even that classification is debated), or ~0.3 million years ago (earliest known remains of Homo sapiens).

For the sake of argument, let’s accept the ~3.3 million year figure, so we can place the beginning of human history and the beginning of the Stone Age at the same point.

Now, back to the question at hand - did the Stone Age represent 99.3% of human history? Given our current body of evidence and our assumption above, it is trivial that the Stone Age did indeed represent 99.3% of years during which humans existed.

But “the years during which humans existed” doesn’t seem to capture what I think of as “human history”. To me, “human history” seems to contain an element of how people actually experience the world around them - humans eat, sleep, love, fight, participate in events, and generally live their lives. To me, that is the stuff that a definition of “human history” needs to capture. If there are twice as many humans walking around on the planet in year X compared to year Y, then we could say that there is twice as much human-related “stuff” happening year X. Under this definition, we could say that year X contains twice as much human history as year Y, despite the fact that both years lasted for the same amount of time.

(We often use an analogous concept as one piece of information when conducting research on farmed animal welfare - if there are twice as many hens living on farm X than farm Y, then all else being equal, a welfare improvement on farm X would be twice as good for hens overall as a welfare improvement on farm Y.)

Now, how has the human population of Earth changed over time? These numbers are from Wikipedia and Our World in Data. Wikipedia has an estimate of ~200,000 humans roughly ~200,000 years ago. Our World in Data begins 10,000 BCE with a population of ~4.4 million, then has estimates every thousand years until 0 CE, every hundred years until 1700, then every decade or year after that. (A tangent, but Wikipedia also has: “A late human population bottleneck is postulated by some scholars at approximately 70,000 years ago, during the Toba catastrophe, when Homo sapiens population may have dropped to as low as between 1,000 and 10,000 individuals.” I’ve ignored that tidbit for this analysis, but isn’t that simply astonishing?!)

Obviously there would be wide error bars for all estimates up until a couple of centuries or even decades ago.

Now, this gives us a very rough idea of how Earth’s human population has changed over time. We could approximate this curve as an exponential growth function (many people have done this). For the sake of argument and for simplicity, let us make the simplifying assumption that the population in some year is equal to the population in the most recent year for which we have data.

Under this assumption, then there have been approximate 2.20x10^12 human-years lived since 3.3 million years ago. Since around 5,000 years ago, there have been 2.11x10^12 human-years lived.

This means that the Stone Age only captures ~4% of human history as I conceive it. This is very different to “99.3% of years since humans have existed”. In other words, almost all human experience has occurred in the Bronze Age and the Iron Age.

The final number would be highly dependent on your assumptions about historical population sizes, and I’m sure this topic has been explored in detail by actual experts. This mostly demonstrates that it can be useful to think about human history not as the duration of time between two dates, but as the sum of people’s experiences and the events in their day-to-day lives - the bulk of which has occurred in the disproportionately recent past.