I'm surprised by how many ppl have told me they don't think there exist any "unpopular but correct" ideas. Past generations were wrong about lots of things in science, ethics, etc; what's the chance we just happen to be the first ones to have figured *everything* out correctly?
The problem is that it's extremely easy to identify the unpopular but correct ideas and everyone knows that. If anyone admits to knowing that there are unpopular but correct ideas he's admitting to believing in the exact ideas that are unpopular because they're correct.