Translated from Russian original by Joanna Dobson

In the 21st conversation, when I am talking about the history of the emergence of natural numbers, I put forward the supposition, that before the appearance of natural numbers, early humans used different methods for counting different kinds of objects.

Just the other day, a fellow mathematician told me that he once read an ethnographic article about a primitive tribe living in the Amazon jungle still isolated from the outside world. Apparently, at the time the article was written, the tribe in question still weren’t using natural numbers. They had different counting systems in everyday use, one system for counting oblong shaped objects and another for counting round objects.