He&#x27;s probably right. If learning curves have decreasing returns, you can get most of the learning in the first section of time.<p>For instance, you can read an introductory text in Economics, Physics, Biology, and so on, and you&#x27;ll know quite a bit about each subject: the subtopics, the main themes, open questions, and the relevant names.<p>Or if you pick up three Economics books, you will know a bit more about some specific ideas (monetary theory, Keynesianism, financial economics, etc...) and nothing about Biology and Physics. But you still won&#x27;t be anywhere near the level where you can teach economics.<p>This is why it&#x27;s easy to sound well rounded but hard to be an authority.