Until recently, such a question did not even arise among the higher primates of the genus Homo. Research shows that for a long time, people of different species lived side by side on our planet - Homo sapiens, Homo erectus, Homo neanderthalensis, Homo denisova, Homo soloensis and many others. But ten thousand years ago, it was Homo sapiens who began to rule. The author of “Homo sapiens” notes that this fact looks quite suspicious. Harari writes that just thirty thousand years ago, one tribe could defeat the tribe of its neighbors in order to occupy land richer in resources. So it may turn out that the wars of ancient tribes somewhere on the Danube were bloodier than the entire history of the twentieth century, including both world wars.

So what kind of “glue” exists to keep people living together today? Harari believes that shared beliefs may be such a glue. For example, the belief that colored letters and numbers printed on paper, as well as computer code that allows transactions between accounts, are money that has value. Today we can top up our phone account, make a charitable contribution, or buy a dress in one click. And all because our ancestors once believed: fresh fish or sweet fruit are worth several shells. Today we use a script instead of shells, but this does not change the essence.