In the 19th century William Whewell developed concept of "Consilience of Inductions". Evidence from independent, unrelated sources can "converge" on strong conclusions. We should feel more confident about our conclusions when we have lots of lines of evidence that stand alone independently, preferably collected by different people, in different parts of the globe or at least different universities. Maybe they don’t even like each other.

Many contrarian views grow long time in small small minded groups or even withing one individual. They have high internal consistency and logic. When exposed to outsiders, they usually spot some obvious errors immediately.