That's all we have. There are no other options, even for people who dislike the word faith. They, and most other people, have an emotional attachment to their World View. It gives them stability and power. Some time in the evolution of shamanism someone observed that different world views have different advantages.
Some belief systems are more effective under some conditions than other systems.
This person was the first true shaman. To the shaman this isn't just an intellectual exercise. The concrete unchanging world changes in step with the accepted thoughts of the people who make up that world. Surprising new discoveries don't reveal previously hidden facts about the world, they reveal a shift in beliefs. The most effective world view is often the world view of someone the shaman is trying to help.