When I read a nonfiction book that has points to make, I often find myself in a debate with the author. I bring up counter-examples. I construct parallel tracks of thought, with facts they omit, that lead to contrary conclusions. I point out where their reasoning by analogy breaks down, and I call the word “obviously” a euphemism for “because I say so.” I do this whether I disagree with the author or not. “Sapiens” is a good book to argue with.