A magician is any practitioner of magic; therefore a magician may be a specialist or a common practitioner, even if he or she does not consider himself a magician. All that is required is the possession of esoteric knowledge, traits, or expertise that are culturally acknowledged to harbor magical powers.
Magical knowledge is usually passed down from one magician to another through family or apprenticeships, though in some cultures it may also be purchased. The information transferred usually consists of instructions on how to perform a variety of rituals, manipulate magical objects, or how to appeal to gods or to other supernatural forces. Magical knowledge is often well guarded, as it is a valuable commodity to which each magician believes that he has a proprietary right.
Yet the possession of magical knowledge alone may be insufficient to grant magical power; often a person must also possess certain magical objects, traits or life experiences in order to be a magician. Among the Azande, for example, in order to question an oracle a man must have both the physical oracle (poison, or a washboard, for example) and knowledge of the words and the rites needed to make the object function.
A variety of personal traits may be credited to magical power, though frequently they are associated with an unusual birth into the world. For example, in 16th century Friuli, babies born with the caul were believed to be good witches, benandanti, who would engage evil witches in nighttime battles over the bounty of the next year’s crops.
Certain post-birth experiences may also be believed to convey magical power. For example a person’s survival of a near-death illness may be taken as evidence of their power as a healer: in Bali a medium’s survival is proof of her association with a patron deity and therefore her ability to communicate with other gods and spirits. Initiations are perhaps the most commonly used ceremonies to establish and to differentiate magicians from common people. In these rites the magician’s relationship to the supernatural and his entry into a closed professional class is established, often through rituals that simulate death and rebirth into a new life.
Given the exclusivity of the criteria needed to become a magician, much magic is performed by specialists. Laypeople will likely have some simple magical rituals for everyday living, but in situations of particular importance, especially when health or major life events are concerned, a specialist magician will often be consulted. The powers of both specialist and common magicians are determined by culturally accepted standards of the sources and the breadth of magic. A magician may not simply invent or claim new magic; the magician is only as powerful as his peers believe him to be.
In different cultures, various types of magicians may be differentiated based on their abilities, their sources of power, and on moral considerations, including divisions into different categories like sorcerer, witch, healer and others.