The subject of demonology has fascinated me ever since I first began reading scary stories as a child. In our culture today, the belief in demonic spirits continues to play a role in literature, movies, and religion. The recent stories about Rabbi Batzri and his exorcisms show that in Haredi and Hassidic communities, the belief in demonic possession is still very much alive and well–irregardless whether such malevolent entities exist or not.
In the world of the psyche, the imagination runs amok in our unconscious and conscious minds. Our dreams bear witness to this mysterious reality where the line between the real and the unreal seem to conflate. The Talmud actually has a pretty sophisticated treatment of demons. In one of the more remarkable passages of the Talmud, we find:
Abba Benjamin says, If the eye had the power to see them, no creature could endure the Mazikin [the “damagers”]
Abaye says: They are more numerous than we are and they surround us like the ridge round a field.
R. Huna says: Every one among us has a thousand on his left and ten thousand on his right (Psalm 91:7).
Raba says: The crushing in the Kallah lectures comes from them. Fatigue in the knees comes from them. The wearing out of the clothes of the scholars is due to their rubbing against them. The bruising of the feet comes from them. If one wants to discover them, let him take sifted ashes and sprinkle around his bed, and in the morning he will see something like the footprints of a rooster. If one wishes to see them, let him take the placenta of a black she-cat that is the offspring of a black she-cat that is the first-born of a first-born, let him roast it the placenta in fire and grind it to powder, and then let him put some into his eye, and he will see them. Let him also pour it into an iron tube and seal it with an iron signet that they the demons should not steal it from him. Let him also close his mouth, lest he come to harm.
R. Bibi b. Abaye did so, saw them and came to harm. The scholars, however, prayed for him and he recovered.
Most of you reading this probably think some of the rabbis may have been taking hallucinatory drugs. This is one interpretation we cannot rule out. As we suggested above, the rabbis might have been describing frightening dreams or nightmares they experienced. We do not really know the original context that fueled these interesting discussions. In the spirit of open-minded discussion, it pays not to rush and invalidate points of view that we make find disagreeable.
Jewish Rationalism to the Rescue!
Rationalists like Maimonides, Ibn Ezra, and Gersonides viewed demons, amulets, and other talismans as superstitious beliefs. The fact that these medieval scholars espoused such an unpopular idea, sets them apart from the rest of the medieval world that accepted these folk beliefs. In one Talmudic passage we find,”It was taught: If food and drink are kept under the bed, even if they are covered in iron vessels, an evil spirit rests upon them” ergo, one should not eat the food.  Note how Maimonides reconstructs the law, “A person should not place a cooked dish under the couch on which he is reclining, even though he is in the midst of his meal, lest an entity that could harm him fall into the food without his noticing.”  True to form, Maimonides demythologizes the Talmud, and one does not find any references of demons throughout his Halachic work.
The Invisible World Within Us
Maimonides’ interpretation is interesting from a more modern and scientific perspective. If the human eye were capable of seeing the actual size of bacteria and parasites that exist on the human body, one would certainly go mad. Scientists observe that the human body is made up of more bacteria than anything else. Millions of bacterial cells found within one human body are could probably fill a half-gallon jug! Each of us is one big playground for all kinds of germs and fungi. Bodily bacteria serves both negative and positive functions; some perform essential actions – like helping us process food while others occasionally mutating to make us ill. The hydrochloric acid in the human stomach can destroy virtually all bacteria, but there is a resilient type of species called Helicobacter pylori that is the exception to the rule. This germ is capable of penetrating and colonizing the mucus lining of the stomach, where it can cause a number of gastrointestinal diseases like peptic ulcers and gastritis.
Fellow blogger named Aharon Varady came up with an ingenious concept that is intriguing. According to him, the Talmudic passage we have here may be referring to an illness called Charles Bonnet Syndrome (CBS). This disease is characterized by bizarre and vivid visual hallucinations. Interestingly, people who suffer from CBS aren’t mentally ill but have visual impairments such as macular degeneration. Even weirder is that the hallucinations often involve characters or things that are much smaller in size than reality.
Of course, each of the four interpretations we have given so far represent a more modern re-reading of a Talmudic text, but the beauty of the Talmud is the fact that even its most arcane sections can lead to some very fascinating deconstructions.
 BT Berakhot, 6a.
 Maimonides, MT Hilchot Gerushin, 2:13; Guide, i. 7; Maimonides’ Commentary to Mishnah Pesachim 4: 11, and Abot 5:6; Ibn Ezra on Lev. 17: 7. Each of these scholars denied the existence of demons.
 BT Pesachim 112a.
 Maimonides, MT Hilchot Rotseach 12:5.