The premise of the book is simple enough. Basically, his thesis is that we think we know more about the world than we really do, and that there are “Black Swans” out there that exist beyond any models of forecasting we can build. The Black Swan notion comes from the belief people had for centuries - that all swans were white because no one ever saw a black swan, until they discovered it in Australia. Because people tend to imagine the world based on their empirical observations, people tend to have a “confirmation bias” that makes them notice things that fit their worldview, and ignore what they can’t fit in.