In so far as Jewish lore goes, the virtues of alert domestic household guardians in disposing of wayward lizards was recognized as early as 350-371 CE in the Babylonian Talmud. The source below, Tractate Pesaḥim, Chapter 10, p112b, provides something of a utilitarian justification for the adoption of cats in this regard:

אמר רב פפא ביתא דאית ביה שונרא לא ניעול בה איניש בלא מסני מאי טעמא משום דשונרא קטיל לחיויא ואכיל ליה ואית ביה בחיויא גרמי קטיני ואי יתיב לה גרמא דחיויא אכרעיה לא נפיק ואסתכן ליה איכא דאמרי ביתא דלית ביה שונרא לא ניעול ביה איניש בהכרא מאי טעמא דילמא מיכריך ביה חויא ולא ידע ומסתכן

Rav Papa said: A man should not enter a house in which there is a cat, without shoes. What is the reason? Because the cat may kill a snake and eat it  — now the snake has little bones, and if a bone sticks into his foot it will not come out, and will endanger him. Others say: A man should not enter a house where there is no cat, in the dark [without shoes]. What is the reason? Lest a snake wind itself about him without his knowing, and he come to danger.

Given these concerns, we can only surmise that if Rav Papa were alive today, he might trust his Nehardean home and yeshiva to be free of tiny snake bones thanks to his own autonomous robotic vacuum cleaner, and unselfconsciously walk about in his socks, even in the dark, his tender soles secure. Over here at the Omphalos, we appreciate the common sense of Rav Papa’s colleagues; and we’re rather satisfied with the lap guarding capabilities of our resident felines, Dot, Ivan, and William. We do admit however that in battle with poisonous lizards, our cats would fare far more poorly than Rav Papa or his colleagues assume. If we lived in an area prone to viper attacks, a Roomba might save our cat’s lives as well as our own.

We will just need to remain vigilant. When in viper country we will wear shoes, as the Talmud recommends and wait patiently while DARPA struggles to model the feline brain. When DARPA ultimately succeeds we will upgrade the firmware of our vacuuming robots with the aggressive skills of 4th century Iraqi cats. But unapologetic sentimentalists, we will keep our warm blooded  companions and enjoy their current, if temporary, dominance over their vigilant snake wrestling (and dust fighting) competitors.

In his 1978 essay, “How to Build a Universe That Doesn’t Fall Apart Two Days Later“, Philip K. Dick wrote, “Reality is that which, when you stop believing in it, doesn’t go away.” This ontology is challenged by a syndrome recently brought to my attention in a recent post on boingboing.net, “Hallucinations brought on by eye disease,” wherein David Pescovitz writes,

In recent days, both the Daily Mail and Wired.com looked at Charles Bonnet Syndrome [CBS], a disease 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.

Read the whole post and follow the link to this article at the Daily Mail on Charles Bonnet Syndrome, and this interview at Wired with neurologist Oliver Sachs. Together, they provide an insight for understanding a particularly fascinating method given in the Talmud for seeing Mazikin (lit. harmful spirits, ie. demons). Mazikin are a class of sheydim (animistic spirits) that pervaded the natural world in the Rabbinic Jewish worldview of late antiquity. From תלמוד בבלי ברכות ו׃א (Talmud Bavli Tractate Berakhot, 6a):

תניא אבא בנימין אומר אלמלי נתנה רשות לעין לראות אין כל בריה יכולה לעמוד מפני המזיקין אמר אביי אינהו נפישי מינן וקיימי עלן כי כסלא לאוגיא אמר רב הונא כל חד וחד מינן אלפא משמאליה ורבבתא מימיניה אמר רבא האי דוחקא דהוי בכלה מנייהו הוי הני ברכי דשלהי מנייהו הני מאני דרבנן דבלו מחופיא דידהו הני כרעי דמנקפן מנייהו האי מאן דבעי למידע להו לייתי קיטמא נהילא ונהדר אפורייה ובצפרא חזי כי כרעי דתרנגולא האי מאן דבעי למחזינהו ליתי שלייתא דשונרתא אוכמתא בת אוכמתא בוכרתא בת בוכרתא ולקליה בנורא ולשחקיה ולימלי עיניה מניה וחזי להו ולשדייה בגובתא דפרזלא ולחתמי’ בגושפנקא דפרזלא דילמא גנבי מניה ולחתום פומיה כי היכי דלא ליתזק רב ביבי בר אביי עבד הכי חזא ואתזק בעו רבנן רחמי עליה ואתסי

It has been taught:

Abba Benjamin says, If the eye had the power to see them, no creature could endure the Mazikin.

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 hand 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.

Could Raba’s magic recipe for perceiving demons by placing ash in one’s eye create a condition like Charles Bonnet Syndrome? Could Rav Huna’s 10:1 ratio of ubiquitous albeit invisible demons indicate a left-brained dominance when perceiving/hallucinating these creatures? Curious minds wish to know the answer to these arcane questions. Rav Huna’s midrashic reading of Psalms 91:7 in particular might suggest that these creatures are small and recalls the peculiar reduced stature of the persons in David Stannard’s hallucination.

So it came as a surprise to the 73-year-old when he looked up from his television one evening to discover he was sharing his living room with two RAF pilots and a schoolboy. ‘The pilots were standing next to the TV, watching it as if they were in the wings of a theatre,’ he says. ‘The little boy was in a grey, Fifties-style school uniform. He just stood there in the hearth looking puzzled. He was 18 inches high at most.’

Just in case anyone is worried, according to Jewish lore the likelihood of perceiving sheydim and “being brought to harm” is substantially reduced if one avoids ruins, wetlands, and other lonely places — and travels in groups of three or more. According to the following argument inברכות מג ב (Tractate Berakhot 43b):

רב זוטרא בר טוביה אמר רב אבוקה כשנים וירח כשלשה איבעיא להו אבוקה כשנים בהדי דידיה או דילמא אבוקה כשנים לבר מדידיה ת”ש וירח כשלשה אי אמרת בשלמא בהדי דידיה שפיר אלא אי אמרת לבר מדידיה ארבעה למה לי והאמר מר לאחד נראה ומזיק לשנים נראה ואינו מזיק לשלשה אינו נראה כל עיקר אלא לאו שמע מינה אבוקה כשנים בהדי דידיה שמע מינה

R. Zutra b. Tobiah further said in the name of Rab: [To avoid danger while traveling in darkness] a torch is as good as two [companions] and moonlight is as good as three. The question was asked: Is the torch as good as two [people] including the carrier [of the torch], or as good as two besides the carrier? [The first argument would require one to travel in darkness with at least one torch and one companion. The second argument would allow one to travel alone so long as they carried a lit torch with them. -- aharon]

Come and hear: ‘Moonlight is as good as three [traveling companions]‘.

If now you argue, ‘including the carrier,’ [then] there is no difficulty. [The torch carrier will need an additional companion.] But if you say, ‘besides the carrier’ [then there is a problem with your argument]. Why would I need four, seeing that a Master has said: “To one [person] a Mazik may show itself and harm them; to two it may show itself, but without harming them; to three it will not even show itself“? [With the 'besides the carrier' argument, four would equal the traveler plus the additional three virtual companions provided by the moonlight. Meanwhile only three are actually needed per the Master's teaching concerning demons. --aharon]

We must therefore conclude that a torch is equivalent to two [persons] including the carrier; and this may be taken as proved.

In darkness, two people can see a demon but not be harmed. Only without the company of another can one both see and be harmed thereby. However irrational this idea appears on the surface, on deeper reflection I think one can see the logic of it. Rationally, one may interpret the mazikin as outward personifications of ever present danger or as dangerous constructs of one’s own imagination. One can endanger themselves, when stumbling about in darkness alone. When isolated from others, one’s imagination can leave themselves into madness. And in the company of two, one is still vulnerable to the Folie à deux. Only with the reality confirmation (and distraction) of friends can what is real be parsed from what is imaginary. (Perhaps for this same reason, a court of judges in Jewish law must be composed of a minimum of three persons.)

Jorge Luis Borges' Jewish Demons as illustrated by the graduate students in the Department of Illustration and Art of the Book at the Vakalo School of Art and Design in Athens, Greece for Borges' The Book of Imaginary Beings.

The image at the top of this post is a painting by Jesse Patrick Martin entitled “Litterbox” and inspired by the defecation of the animals in Borges’ Beastiary. (Used with the artist’s permission. Please visit Jesse’s site for more fantastic work.)