A cognate of "guest," both words rooted in Germanic Geist, originally a spirit of a dead ancestor invited to tribal feasts on such occasions as Samhain (Halloween) and other solemn ceremonies. Many European peoples preserved the heads or skulls of ancestors, which were set up, painted, and decorated, in a prominent position at gatherings of the clan, and were consulted for oracles after being offered their portion of the collation. Hence the "Death's-head at the feast." During later Christian times the custom was discouraged, for the church's doctrine of resurrection of the flesh forbade burial of bodies without heads. Nevertheless, the visiting ghost was an ineradicable belief. Ghosts were supposed to haunt all the scenes of their former lives, especially if they died violently or unhappily, or were buried in unconsecrated ground, or had possessed evil spirits. The earlier, more benevolent type of family ghost is still suggested by the identical pronunciation of "ghost" and "guest" in northern England. The anger of ghosts was most feared by people who refused to honor them as guests.
This vital energy has its origin in the spiritual body of the earth. Every created thing has two bodies, one visible and substantial, the other invisible and transcendent. The latter consists of an ethereal counterpart of the physical form; it constitutes the vehicle of archæus, and may be called a vital body. This etheric shadow sheath is not dissipated by death, but remains until the physical form is entirely disintegrated. These "etheric doubles, "seen around graveyards, have given rise to a belief in ghosts. Being much finer in its substances than the earthly body, the etheric double is far more susceptible to impulses and inharmonies. It is derangements of this astral light body that cause much disease. Paracelsus taught that a person with a morbid mental attitude could poison his own etheric nature, and this infection, diverting the natural flow of vital life force, would later appear as a physical ailment. All plants and minerals have an invisible nature composed of this "archæus," but each manifests it in a different way.
Though it was by this time very difficult for the higher spiritual beings, the gods, to squeeze down into a dense, material realm, it was relatively easy for lesser spirits, such as demons and spirits of the dead.