One hundred years ago (January, 1912), at the annual meeting of the Geological Association in Frankfurt, Germany, Alfred Wegener, a meteorologist, presented his theory of continental drift for the first time. It was almost uniformly dismissed by geologists. One of them called it “mere geopoetry”. Much later, he was proved right.
To me, this is a classic example of the power of what I call insider/outsiders. Wegener had a great deal of scientific training, including a Ph.D. in astronomy. Unlike professional geologists, however, (a) he had the freedom to say whatever he wanted about geology without endangering his job (as a meteorologist) or prospects for advancement and (b) was under no pressure to publish. He could spend as much time on his theory as he wanted.