Dear Jeppe M.,

Ghosts are departed souls that continue to sojourn in the physical world rather than entering higher spiritual domains. Our sources offer several explanations for this. One is that a soul that is reincarnated three times without repair is not permitted to gehinom, nor to be reincarnated again; rather it is forced to wander bodiless in this world (see Ask the Rabbi Reincarnation). Such a bodiless, wandering soul may eventually cleave to a living person resulting in the phenomenon of dybuk.

Another explanation is premature death. Our Sages taught, "Once tragedy is let loose, it doesnt differentiate between innocent or guilty". Without delving into the issue of how one may "die before his time", a prematurely disconnected soul is incomplete and seeks to remain in this world to fulfill its purpose. Such a souls presence in this world is perceived as a ghost.

The British Society for Psychic Research, a group of qualified scientists, asserts that while most ghost reports are due to illusion, many seem to be verified. Their studies show that in cases where ghosts were reported as a result of sudden tragic deaths, people totally unaware of the death attested to "feeling" something in the house. Animals in particular seem to have this sense. In a "haunted" Kentucky home, a cat, a dog, and a rattlesnake all reacted strongly against a certain unoccupied chair in the house. This is consistent with the teaching of our Sages, "When dogs bark [incessantly], the Angel of Death is in town".

There are several explanations as to how we sense the presence of a bodiless soul. For one, just as a person sees another person, so ones soul perceives the presence of another soul, giving one the unexplainable feeling that "something is there". Alternatively, the soul senses being "stared" at by the bodiless soul, just as a person can often feel when someone is staring at him. Regarding this the Rabbis taught, "Even though a person doesnt see, his mazal sees". This means that the soul perceives and interacts with unseen spiritual forces that the conscious mind is unaware of except for a faint impression. In addition, the Kabbalists teach that even though a soul is basically ethereal, it nevertheless has some physical mass (called tzelem or guf hadak) that can be felt by a sixth, subconscious sense.

A well-known account in Tanach in fact deals with the appearance of a "ghost". In an act of despair, King Saul commissioned a witch to summon the soul of the prophet Samuel: "And the woman saw Samuel, and she cried aloud.And Saul said to her, What is his form? And she said, An old man is coming up, and he is wrapped in a cloak. And Saul knew that he was Samuel" (I Samuel 28). Rashi explains that when one summons through a medium, the medium sees but doesnt hear; the one who summons hears but doesnt see. Ralbag (Rabbi Levi ben Gershom 1288-1344) notes in either case the apparition is not a real sight or sound, but neither is it imaginary or a hallucination, but rather an "illusion" of a spiritual reality. In this vein Rambam states, "The forms that are devoid of matter cannot be perceived with the physical eye but only with the minds eye".

The Talmud also records several "ghost sightings". After Rabbi Yehuda HaNasi Rebbe died, he would return to his home every Sabbath Eve. Once, a neighbor came speaking very loudly when Rebbes maid whispered, "Be quiet, Rebbe is sitting there". When he heard this, he came no more, in order not to slight the honor of earlier rabbis. In another account, Rabbi Akiva once saw an apparition enduring great punishment. He asked why it must suffer so, to which the soul replied that he had committed many severe transgressions. Rabbi Akiva asked, "whom did you leave behind", to which he responded "a pregnant wife". Rabbi Akiva found the woman, waited until she gave birth to a son, circumcised him, and taught him to pray and learn Torah. Eventually the apparition reappeared to him and said, "May your mind be put at ease for you have put my mind at ease."