I call myself a kupua, which is a Hawaiian word for a shaman found among the traditions of Polynesia. There are many definitions of shamanism, but few mention the core of shamanistic belief that I learned from my teachers. Most definitions talk about what shamans do rather than what shamans believe .
Shamans use whatever tools they know that seem appropriate for the circumstances.
A listing of these tools doesn't constitute a precise meaning of the limits and uniqueness of shamanism. If a person tries to learn about shamanism by studying what a shaman does, many things will seem to be inconsistent and illogical. Progress will be slow, especially if the person is a product of modern Western thought. Some are our own ideas. No one can prove their own axioms to anyone else if the other person has a different set of axioms.