The key insight that shapes the frame of the book is the concept of the mind as a tool for generating predictions about the future. It's a lot easier to learn by trial-and-error if you can learn from other people's errors ("Bob jumped off the cliff, fell down and isn't getting back up. Following Bob is probably a bad idea"), but also if you can extrapolate into different-but-similar situations (This tree is kind of like the cliff Bob jumped off. I should probably climb down instead of jumping)