It is the inarguable scientific consensus that early humans began developing stone tools between two and three million years ago, when the climate was undergoing a period of rapid change. African forests in the area we now know as Kenya were transforming into grasslands: The only way our ancestors could survive was by inventing tools.
Or at least that was the scientific consensus.
A fascinating story in the May issue of Scientific American reveals that the ballyhooed scientific consensus has just been blown to smithereens: Recently discovered stone tools appear to be some 3.3 million years old. That is, they predate the period of climate change that according to the scientific consensus had spurred early man to develop tools. That’s right—one new discovery was enough to overturn what had been the unimpeachable scientific consensus. And the story was climate-related to boot!
Far be it from The Scrapbook to suggest that the current scientific consensus of anthropogenic global warming might find itself similarly overturned someday. But given that new discoveries have more than once overturned the conventional scientific wisdom—think of the end of geocentrism, the discovery of plate tectonics, and now the rethinking of when hominids developed tools—a bit of epistemological humility can go a long way.
