The techniques they espouse resemble the apparatus of the occult. Read, for example, this list of definitions from a standard dictionary (Webster’s Ninth New Collegiate Dictionary):
Clairvoyance: The power or faculty of discerning objects not present to the senses....the ability to perceive matters beyond the range of ordinary perception.
Divination: The art or practice that seeks to . . . discover hidden knowledge.
Magic: An extraordinary power or influence seemingly from a supernatural source.
Medium: An individual held to be a channel of communication between the earthly world and a world of spirits.
Wizardry: A seemingly magical transforming power or influence.