FiveThirtyEight interviews Caleb Everett, author of Numbers and the Making of Us: Counting and the Course of Human Cultures.
Numbers may feel instinctual. They may seem simple and precise. But Everett synthesizes the latest research from archaeology, anthropology, psychology and linguistics to argue that our counting systems are not just vital to human culture but also were invented by that culture. “Numbers are not concepts that come to people naturally and natively,” he writes. “Numbers are a creation of the human mind.”
I spoke to Everett by phone about the book.
Craig Fehrman: Are human beings hardwired to think numerically?
Caleb Everett: We seem to have some kind of innate predisposition to numbers, but it’s smaller than you’d think. At an early age, we have the ability to tell the difference between bigger groups — between, say, eight things and 16 things. We can also tell one thing from two things or two things from three things. But other primates like chimps can do that. And once you get to four things, it starts to get tricky.
CF: That’s where numbers come in, right? In your book, you suggest that our five-fingered hands — and the fact that we walk on our legs and keep those hands free — may have played a big role here.
CE: My suspicion is that there were many, many times in history when people realized in an ephemeral way that this quantity is the same as that quantity — that this five, in terms of their fingers, is the same as that five, in terms of goats or sheep. It’s no coincidence that many unrelated languages have a numerical structure built around 10 or that the word for five is often the same as the word for hand. Once someone else heard you referring to something as a “hand” of things, it became a cognitive tool that could be passed around and preserved within a particular culture.
FWIW, it's not at all clear to me why the interviewer, Craig Fehrman, should remark that numbers may feel instinctual. After all we spent hours upon hours as children learning to count and then to do arithmatic, and this training goes on for half a dozen years.