Learning the section of Hoshen Mishpat known as nizkei shekheinim (neighbor damage) is like walking through a city. The student is treated to scenes of citizens renovating, dumping sewage, soaking flax, hammering metal, selling whiskey in an alley, and teaching children. The attention the literature pays to sensory information means students of nizkei shekheinim can smell and hear the text as their minds walk through it. It is possible to feel like one is really there, where “there” is a metropolitan stew of eras and perspectives and situations: dry-heaving with Rav Yosef as he smells the bloodletters next door, or peering through a window with Ramban. In fact, this act of radical presence by a student is not only possible, but is an important strategy for understanding the material. Sometimes there are unaccountable discrepancies between the technical requirements of one ruling and the next. Only by being there can a student understand what makes, say, a standard measurement only sometimes good enough. An example of a discrepancy best solved by presence is hezeik re’iyah (“sight damage”). Hezeik re’iyah can generally be prevented with a barrier four amot high, but, in Hoshen Mishpat §160 the barrier must be potentially much higher. I will explain.
In nizkei shekheinim, neighbors damage one another in many ways: mismanaged water disposal, noise pollution, and the buildup of hazardous material. Along with this familiar list of concerns, Jewish law places special and perhaps unique emphasis on hezeik re’iyah, i.e., the harm one neighbor inflicts on another simply by looking at them – especially by having the opportunity to look at them through an imprudently-placed window. What is the nature of this harm? First, the neighborly relationship degrades as curiosity slides into compulsion and prurience, a downward spiral rabbis do not believe people can prevent by willpower alone. Second, the neighbor under surveillance is subject to the anxiety of not knowing when and for how long they may be watched, or what the emotional state of the watcher may be (e.g., hostility, jealousy, attraction). Such anxiety impedes a person’s ability to conduct their business unselfconsciously and with their accustomed skill, an interference classically expressed as ayin hara. There is no need to be vexed by this introduction of an apparently supernatural concern. Anyone who has had to perform an intricate task in front of a rival understands precisely the phenomenon being referenced.
Halakhah acts to mitigate hezeik re’iyah by regulating lines of sight, including both one’s view into a neighbor’s home and that neighbor’s own view out of their home. Indeed, halakhah appears to reject any simplistic dichotomy of insiders looking out and outsiders looking in. One may not open a window in their own house with a view to their neighbor’s hatzeir if that neighbor objects. A shared outdoor workspace must be partitioned if doing so is practically feasible. In fact, Rosh asserts that all outdoor workspaces – shared or not – should be fenced, even if the local custom is not to fence them.
It is not easy to articulate a single, universal principle to describe upon whom the responsibility for privacy devolves. If the vulnerability of two neighbors is more or less symmetrical, both of them shoulder the burden of constructing a wall. If the threat is asymmetrical, the burden is similarly asymmetrical, and the least vulnerable party is usually responsible. Thus, mitigation of hezeik re’iyah is a massive, multi-faceted discussion, but one fiercely grounded in direct human experience. Again and again, the questions asked are: How do humans really behave? What kind of physical structures present reasonable barriers to a curious neighbor? Because the halakhic discussion flows from real life, not from symbolic or technical concerns, it remains lucid and memorable no matter how intricate its investigations become. By vividly picturing the problem described, a student can readily understand the range of responses given by the rabbis. If a ruling is thought to make no practical sense, it is immediately called out by other voices on the page.
Yet one major inconsistency is left largely unexplained. Although four amot is thought to be a sufficient barrier for privacy, in Hoshen Mishpat § 160 we learn that when one house is located under a cliff, and another house is located at the top of the cliff, the house at the bottom is obliged to build a partition up to the ground level of the top house, plus four amot, in order to prevent hezeik re’iyah. This is a towering barrier indeed, seemingly far beyond what is normally called for. Yet, curiously, only R. Yehudah Bartseloni (a medieval halakhic codifier in Spain) holds that the cliff itself constitutes a sufficient partition.
Visualizing the situation highlights what is confusing about it. How, from the bottom of a cliff, is one likely to spy on a property on top of it? Rosh, perhaps the only rabbi to confront this question head-on, suggests that the upper neighbor might walk right along the edge of the cliff, and therefore is unusually vulnerable to hezeik re’iyah even from far below. This explanation does not, however, explain why §160 differs from the window-related concerns of §154, where a much lower barrier is mandated: just as the upper neighbor of §160 could walk along the edge of their cliff, so too could the indoor neighbor of §154 sit directly in their windowsill. We are left with no satisfying explanation as to why one measurement, four amot, is not good enough for the housing arrangement depicted in §160 along with the others from §154.
There are additional reasons to wonder at the very high barrier required in §160: the expense and technical difficulty of constructing such a massive barrier are daunting. We see in Bava Batra 6b that a much smaller wall of only ten tefahim is considered a serious structural burden which people avoid undertaking if they can. The cliff situation is all the more baffling considering that people who live on lower ground are likely to be poorer than those who live above them. Why place an outsized burden on one who is least capable of bearing it?
As mentioned, hezeik re’iyah is a problem usually processed through the lens of common sense. As an example, we can look to the halakhah about building walls near other people’s windows: the walls must be either higher than the window by four amot (the standard human body height), or lower than the window by four amot, to prevent one neighbor using the wall to peer in the other neighbor’s window. Further illuminating the focus on practical, physical concerns, we have an interesting teaching by Rav Zevid, who says that one can build a wall closer to another’s building if the surface of the wall is sloped, thereby making it difficult to stand on and thus use to spy on the person inside. So: why is the same standard of four amot not enough in §160? In other words, why is the opinion of R. Yehudah Bartseloni not the common consensus?
We can solve this problem not by abandoning visualization and common sense, but by doubling down on them. It is first necessary to query if this is really a case of inconsistency. What is the difference between a wall under a window and a larger surface such as a roof or hatzeir under a window, such that they have different distance requirements? As much as we have considered that it may be difficult for a person at the bottom of a cliff to spy on a household on top of the cliff, we can consider that it is all the more difficult for the household above to keep track of what is going on below, and especially to notice any infrastructure being constructed along the face of the cliff. Because of the possibility of building unnoticed scaffolding, it could actually be easier to inflict hezeik re’iyah than if one had a narrow wall under a window, which would be a precarious surface on which to balance a ladder or the like. Visualize walking along a cliff near your house – you will not easily see if your neighbors are below, even if you are alert and looking out for them. Visualize the position of the lower neighbor – you have a possibly scalable surface in front of you which is nicely hidden from the view of anyone above. It is this asymmetry of vulnerability which causes responsibility to devolve onto the lower neighbor.
This very observation can be seen at work in R. Yosef Karo’s ruling in Shulhan Arukh, Hoshen Mishpat § 154:6, that one cannot open a window in one’s house onto a neighbor’s hatzeir even if the window seems too high for a person to look through, as the neighbor might use a ladder. It is immediately apparent what is so dangerous about this situation, namely, that someone working outside the house would be unable to see whether or not a ladder had been placed against the window on the inside. It resonates with the insight of Rosh that damage is greater when one cannot reasonably anticipate it and therefore guard against it.
The flip side of the coin is Rav Zevid’s sloped wall. When it is actively impractical or even dangerous to spy, fewer additional barriers are required between neighbors. Here is the key to the problem of someone who simply cannot build a wall high enough to match the height of the cliff, then add an additional four amot. Such a person may have an effective claim that they are like someone with a sloped wall: the very reason they cannot build is the reason they pose little threat with regard to hezeik re’iyah.
With this in mind, it is now possible to reexamine some of the voices disagreeing with R. Yehudah Bartseloni. The disagreement may be more narrow than it first appeared. For example, Rabbeinu Yonah states that if the height gap between the hatzeir above and the dwelling below is large enough, the bottom neighbor can get by with a mehitzah mu’etet, a perfunctory barrier, “to demonstrate to others that he can no longer cause damage by looking.” To R. Yehudah Bartseloni’s basic insight, Rabbeinu Yonah adds a nice touch: the need for a barrier at the top that is less stable than the ground itself, which a potential spy would need to scale. Such a barrier would truly not need to be very tall to make an ascent more precarious. Rabbeinu Yonah’s language also reveals an element of communication. ֽA small barrier broadcasts to the neighborhood that one is aware of one’s boundaries and is committed to them. Small barriers are generally an invitation to others to consider one a “thief” or suspicious actor if one crosses the line, as seen in Shulhan Arukh, Hoshen Mishpat § 159:2. Rabbeinu Yonah’s thought is referenced by Tur and adopted by Rema. This opinion demonstrates the existence of a common ground that, where hezeik re’iyah would be difficult and dangerous to inflict, the requirement to build a high barrier is at the least seriously relaxed.
On the other hand, a commentator on Shulhan Arukh, Sefer Me’irat Einayim (known as Sm”a), suggests that R. Yehudah Bartseloni himself would concede that a higher barrier would need to be constructed if the gap between neighbors were smaller than four amot. In other words, R. Yehudah Bartseloni’s imaginative default was a situation in which it was absurd to suspect that the lower neighbor was spying on the upper neighbor, and therefore would have been open to a more stringent guard of the upper neighbor’s privacy if and where spying would become plausible. The insight of Sm”a is that, often, formal disagreement is the product of imagining different pictures, pictures which may or may not be explicitly described in a given opinion. What goes into the production of any person’s default picture of a situation is life experience, whether obvious and concrete like the architecture of one’s city of residence, or as ephemeral and human as the hand gestures of one’s teacher when demonstrating this high or this low.
The rabbinic discourse around hezeik re’iyah prompts students to be careful and curious about disagreements. When an opinion is truly surprising, the nizkei shekhenim material demands a thoughtful response which has as its first step an act of investigative imagination, seeking to discover and share the vantage point of the author. From that first step, others follow: discerning if this vantage point matches that of others or not, and in what ways. This process of presence is equally important for opinions which do not seem immediately confounding. Too often, students are trained to reduce halakhic disagreement to technicalities, ritual requirements which do not have to make sense. But such reduction robs us of the chance to see how the rabbis respond to real life and say things which are meaningful. By participating in the same acts of presence exercised within rabbinic literature itself, students sensitize themselves to the real life issues at stake, thereby enabling them to make authentic sense of halakhah.
 See Shulhan Arukh, Hoshen Mishpat §§ 153-156.
 See Bava Batra 23a.
 See Beit Yosef, Hoshen Mishpat § 154:5.
 See Bava Batra 2b.
 Rashba quoted in Beit Yosef to Tur, Hoshen Mishpat § 154:17.
 See Rashi to Bava Batra 2b, s.v. “asur le-adam she-ya’amod, etc.”
 This term refers to a courtyard, in the sense of the outdoor space adjacent to a dwelling. Many tasks which we now associate with indoor work were once performed in a hatzeir and were thus vulnerable to hezeik re’iyah.
 Window regulations constitute the bulk of Hoshen Mishpat § 154.
 Ibid. § 157:1.
 See Tur, Hoshen Mishpat 157:4.
 See the response to Rashi by Beit Yosef to Tur, Hoshen Mishpat § 154:22, especially the expression of the nature of his objection: “ve-zeh davar murgash la-hush” (“and this is a matter felt by the sense[s]”).
 Shulhan Arukh, Hoshen Mishpat § 160:1.
 Tur, Hoshen Mishpat §160:2.
 Hiddushei Ha-Rosh to Bava Batra 1:17.
 In various responsa referenced in §153, we see one reason why dwellings on low ground can be undesirable: increased water damage from houses above. See, e.g., the responsum of Rashba quoted in Beit Yosef to Tur, Hoshen Mishpat §153:19.
 Shulhan Arukh, Hoshen Mishpat §154:21.
 Bava Batra 22b.
 Teshuvot Ha-Rosh 100:6:3.
 Tur, Hoshen Mishpat § 160:3.
 Rema to Shulhan Arukh, Hoshen Mishpat § 160:3.
 Sm”a to Shulhan Arukh, Hoshen Mishpat § 160:3. See, however, Ketzot Ha-Hoshen, ad loc.