I think that might be a matter of divergence from source, though. Most people can't afford the time to debate every idea that they accept over their lifetimes.

I think that might be a matter of divergence from source, though. Most people can't afford the time to debate every idea that they accept over their lifetimes. So, if you get someone who heard something from someone they trust that heard it from someone THEY trust who is doing actual work on the subject... that's not too far removed from a primary source, so the twice-removed observer is likely to accept that fact as Good Information and move on.