Mediumship is the practice of certain people—known as mediums—to purportedly mediate communication between spirits of the dead and other human beings.
There are several different variants of mediumship; the best known forms are where a spirit takes control of a medium’s voice and uses it to relay a message, or where the medium simply ‘hears’ the message and passes it on. Other forms involve manifestations of the spirit, such as apparitions or the presence of a voice, and telekinetic activity.
In Spiritism and Spiritualism the medium has the role of an intermediary between the world of the living and the world of spirit. Mediums claim that they can listen to and relay messages from spirits, or that they can allow a spirit to control their body and speak through it directly or by using automatic writing or drawing.
Spiritualists classify types of mediumship into two main categories: “mental” and “physical”:
Mental mediums allegedly “tune in” to the spirit world by listening, sensing, or seeing spirits or symbols.
Physical mediums are believed to produce materialization of spirits, and other effects such as knocking, rapping, bell-ringing, etc. by using “ectoplasm” created from the cells of their bodies and those of seance attendees.