The late, brilliant alternative thinker Terence McKenna spoke eloquently about the shaman's role in society. Many videos, articles and interviews are available which present McKenna's thinking and experiences. These ideas have helped me reflect on my own path.
The shaman is someone who has... stepped outside the confines of learned culture and learned and embedded language, into the domain of what Wittgenstein called "the unspeakable", the transcendental presence of the other [to gain] knowledge which can be brought back into ordinary social space for the good of the community. So in the context of ninety percent of human culture, the shaman has been the agent of evolution, because the shaman learns the techniques to go between ordinary reality and the domain of the ideas. This higher dimensional continuum is somehow parallel to us, available to us, and yet ordinarily occluded by cultural convention (out of fear of the mystery). And what shamans are, I believe, are people who have been able to de-condition themselves from the community's instinctual distrust of the mystery, and to go into it, to go into this bewildering higher dimension, and gain knowledge, recover the jewel lost at the beginning of time, to save souls, cure, commune with the ancestors and so forth and so on.