How many different human worlds coexisted on earth? Around 10,000 BC our planet contained many thousands of them. By 2000 BC, their numbers had dwindled to the hundreds, or at most a few thousand. By AD 1450, their numbers had declined even more drastically. At that time, just prior to the age of European exploration, earth still contained a significant number of dwarf worlds such as Tasmania. But close to 90 per cent of humans lived in a single mega-world: the world of Afro-Asia. Most of Asia, most of Europe, and most of Africa (including substantial chunks of sub-Saharan Africa) were already
...more
