What is the etherealist society?

A mythical society made up people who exist only in one's imagination. They require no food or any other physical trappings since their minds create and control all things. Banded together a society of etherealist could create all manner of "things" that a realist would believe actually existed as long as the etherealist mind willed it. A good example of a "etherealist" society is in Edgar Rice Burrough's book "Thuvia Princess of Mars".