There was an entire 'unknown' continent in Columbus' way when he set off for the Indies. He started with the conclusion, and built an argument. A perfect example of confabulation. He even died believing that the West Indies were part of the known world of the Afro-Asian land mass. The Americas are named after Amerigo Vespucci, the first European to theorise that the Old World wasn't the entire world. In 'Sapiens', Harari points out that one of our biggest leap forwards in learning, wasn't our ability to map what we know, but to be able to map our areas of ignorance. Our ability to gain comfort with pointing out the gaps in our knowledge.