I've been reading a most interesting narrative by the Yanomami shaman and spokesman Davi Kopenawa about relations between humans and the ancestral spirits his people call xapiripë. "The xapiripë dance together on huge mirrors which come down from the sky. They are never dull like humans. They are always splendid."
The xapiripë descend to us perched on mirrors, which they keep suspended a little bit above the earth, so they never quite touch the ground. These mirrors come from their home in the sky.
In a shaman’s house of spirits, these mirrors are propped, hung, piled and placed side by side. When the house is big, the mirrors are big. As the number of spirits increases, the mirrors multiply, one on top of the other. The xapiripë don’t mix with each other. They have their own mirrors on the beams of the house: mirrors of warrior spirits, bird of prey spirits, and cicada spirits; mirrors of thunder spirits, lightning spirits, and storm spirits. There are as many mirrors as there are spirits, they are beyond number.
We live among mirrors. Our forest belongs to the xapiripë and is made from their mirrors. 
Mirrors not only hold and reflect images; they multiply them. Thus an ancestral spirit may reappear in many images:
When the name of a xapiripë is spoken, it is not a single spirit we evoke, but a multitude of similar spirits. Each name is unique, but the xapiripë it designates are very numerous. They are like the images in the mirrors I saw in a hotel. I was alone, but at the same time I possessed many images. Thus, there is just one name for the image of the tapir turned into spirit, but the tapir-spirits are very numerous...This is true of all the xapiripë. People think they are unique, but their images are innumerable. They are like me, standing in front of the hotel mirrors. They seem alone, but their images overlap each other as far as infinity. 
This makes us reflect on the importance of mirrors in many shamanic traditions. Looking into a reflective surface may reveal a world beyond the world. A shaman's mirror may be a soul catcher, or a shield, or a place in which to see.
We need to dream deep on the mirrors that Davi describes. The night before I posted this report, a man dreamed that his departed mother appeared to him, offering sage counsel. He described her as standing on a "glassy river" that went up into the sky.
Due diligence: in order to see them and interact with the spirits, Yanomami shamans inhale the powder of the yãkõanahi tree, "the food of the spirits", an item I would not recommend for anyone outside their traditional culture.
Communing with the spirits, says Kopenawa, is "our study; it teaches us to dream."
Someone who is not looked upon by the spirits doesn’t dream. They just lie around in dumb sleep like an ax abandoned on the ground. 
1. Davi Kopenawa and Bruce Albert, "Les ancêtres animaux" in B. Albert and H. Chandes (eds)Yanomami - l'esprit de la forêt Paris: Fondation Cartier / Actes Sud, 2003, pp.72-3.
2. ibid, p.73.
3. Davi Kopenawa, "Sonhos das origens" in C.A.Ricardo (ed) Povos indígenas no Brasil (1996–2000), São Paulo: ISA, 2000.