In Christianity, Docetism is the belief that Jesus did not have a physical body; rather, that his body was an illusion, as was his crucifixion.

This belief is most commonly attributed to the Gnostics, who believed that matter was evil, and hence that God would not take on a material body. This sort of statement, however, is rooted in the idea that a divine spark is imprisoned within the material body and that the material body is in itself an obstacle, deliberately created by an evil lesser god (the demiurge) for this purpose, that prevents man from seeing his divine origin. Humanity is in essence asleep.

Docetism could be further explained as this — the human body is temporary, and the spirit is eternal—therefore, to say that the body of Jesus was an illusion and that his crucifixion was as well, could be compared to the same way a Buddhist speaks about illusion: illusion is everything that is temporary, not everything that is not real. Even so, saying that the human body is temporary has a tendency to undercut the importance of the belief in resurrection of the dead and the goodness of created matter, and is in opposition to this orthodox view.

Docetism was rejected by the ecumenical councils and mainstream Christianity, and largely died out during the first millennium A.D. Catharism, and other surviving gnostic movements, incorporated docetism into their beliefs, but the movement was destroyed by the genocide of the Albigensian Crusade.

Islam also teaches that Jesus's crucifixion was an illusion.

See also: Christology, Avatar