Some other familiar-sounding things: the earth revolves around the sun (Galileo); microscopic organisms exist (van Leeuwenhoek); an invisible force called radiation exists (Marie Curie).

Things do not have to be obvious to be true.

Astronomers and physicists try to detect hidden phenomena by noticing gravitational disturbances. What is so different about detecting unseen activity behind the scenes in the stock market? It's a brilliant and noble pursuit. Someday 4kids will be added to the list above.