All science and scientists works on models of understanding. These models of understanding change over time when new evidence comes about which contradicts the current model or the current model cannot fully accommodate the new knowledge. It does not matter how many or how powerful the followers of the previous model are. For example for many centuries model of blood circulation proposed by Galen, a Greek physician was considered to be the truth. “According to the Galenic system, Blood flows through invisible pores from right side into the left side of the heart. Such an authority was Galen that the practice of medicine was built around his defective understanding of physiology for the next 1500 years. Galen's findings were first challenged in the 1200s by an Arab physician, Ibn-al-Nafiz, who insisted there were no
