[yorwba]

> If you really cared about something, you would read at least one if not multiple books on the subject.

I'm not sure how true that is anymore. If by "book" you mean "monothematic long-form treatise by a small number of authors" then I have read essentially zero books in the past year, although I have done a great deal of reading otherwise. Research papers, magazines, blog posts, Wikipedia articles, cherry-picked single chapters of books can in aggregate absolutely stand in for a few books. And then there are sources of knowledge that go beyond reading, such as personal experience, original research, attending talks, etc.

I think your test would be more accurate if you asked more generally how they learned what they know about the matter.

[BuckRogers]

It probably doesn't apply to you, or a few others in the minority. If you're intelligent enough to be able to identify credible sources vs those which are not, then you're probably better off. I offered that up as a low-bar. That said, usually if you're truly into a given subject you'll eventually find a book by someone that you really want to read.

Example for me other than Marx & Engels that I mentioned elsewhere in this thread, is my passing interest in European Celts. I enjoy reading about Iron Age Europe, so I've had a hard time resisting books on the subject. Caesar's Druids by Miranda Aldhouse-Green was a recent book that I read and something I couldn't pass up. While I accept your statements and agree, I still think the same will be for you if you're truly serious about a given subject.