Shamanism is a range of traditional beliefs and practices that involve the ability to diagnose, cure, and sometimes cause suffering because of a special relationship with, or control over, spirits. This tradition has existed all over the world since prehistoric times. Shamanism is based on the premise that the visible world is pervaded by invisible forces or spirits that affect the lives of the living. In contrast to animism and anatamism, which any and usually all members of a society practice, shamanism requires specialized knowledge or abilities. Shamans are not, however, organized into full-time ritual or spiritual associations, as are priests in shamanic religions a medicine is some magical object or ceremony, such as medicine bag, that is used to control and direct the supernatural forces. The term medicine also refers to the magical potential of the object or ceremony which is used for these purposes. Among North American Indians, a medicine man or medicine woman is someone who professes to have skills at manipulating supernatural forces and uses these skills to cure sickness, drive away evil spirits, and regulate the weather.