you can't beat a good teacher for teaching, but only a fraction of what I know has come from classes -- there are whole fields that I know something about with

you can't beat a good teacher for teaching, but only a fraction of what I know has come from classes -- there are whole fields that I know something about without ever having taken a class in them, and I imagine the same is for you. What happened was that good authors learned to effectively have a dialog with their readers, anticipating their readers' expanding knowledge, what they have probably overlooked, and the questions that would be puzzling them. I doubt Socrates -- or Plato, for that matter -- ever imagined an almost entirely literate society, let alone what powers that would unleash.