Ari Sacher

“It’s Railing Again” Parashat Ki Tetze 5779

The excitement was palpable. After more than fifteen years of construction, our Moreshet Central Synagogue was about to open. The highlight was the main sanctuary, a beautiful edifice with a raised ceiling, the finest seats, and sparkling porcelain floors. However, the day before it opened, we received notice that we would have to wait until “changes were made”. The Israeli Safety and Health Administration demanded that the porcelain tiles near the exits must be replaced with special tiles containing truncated domes that could be tactilely recognized by the visually impaired in case of an emergency exit. The special tiles took two weeks to install. They are an eyesore but the building has been ruled safe.

The Torah is extremely safety-conscious. We are commanded [Devarim 4:15] “You shall watch yourselves very well”. The Sages interpret this as a directive to take care of our bodies and to stay out of harm’s way. Parashat Ki Tetze contains a similar commandment [Devarim 22:8]: “When you build a new house, you shall make a guard rail for your roof, so that you shall not cause blood [to be spilled] in your house”. At first glance, this commandment seems superfluous. Doesn’t it fall under the rubric of “watching ourselves very well”? Further, the Talmud in Tractate Hullin [136a] deduces from the use of the word “ga’gecha” – “your roof” – that a guard rail is not necessary in places that do not have one specific owner, such as a synagogue. It is only required in one’s personal place of residence. That seems completely counterintuitive. One would think that a synagogue, by virtue of the large volume of worshippers, should have greater safety requirements than a home. Moreover, the Talmud in Tractate Shabbat [11a] rules that a synagogue is supposed to be the tallest structure in a town, making a guard rail even more critical. Don’t our Sages [Hullin 10a] tell us that we must be more strict when danger is involved than when a prohibition is involved[1]? Why are we using halachic acrobatics to make our synagogues less safe?

To address these questions, we must take a deep dive into safety. Military systems are, by their nature, fraught with danger, especially those systems that contain pyrotechnic devices like rocket motors and warheads. And so it is impossible to introduce a new system into service until it has been “safety certified”. In order to ensure that a system can one day be certified as safe, nearly all systems have safety designed in from Day 1. This is typically accomplished by designing the system according to the “Bible of System Safety”, otherwise known as MIL-STD-882[2]. According to the document, “Department of Defense is committed to protecting personnel from accidental death, injury, or occupational illness and safeguarding defense systems, infrastructure, and property from accidental destruction, or damage while executing its mission requirements of national defense”.

One would expect that MIL-STD-882 would be thousands of pages long and that it would cover nearly every kind of eventuality. This is not the case. The document is only one hundred and four pages long. It is less an encompassing set of rules than a list of general guidelines. For example, the worst thing that can happen to a missile is uncommanded launch. Imagine an A-10C Thunderbolt II flying somewhere over Tucson, Arizona, and the aircraft suddenly “inadvertently” fires an M-156 rocket, a white phosphorus munition. Whoops. Well, this is precisely what happened last week. Fortunately, the rocket landed harmlessly in a remote dry river bed, but the incident could have just as easily occurred far less harmlessly over downtown Tucson. In order to prevent this sort of occurrence, engineers introduce safety mechanisms in both hardware and software. Their goal is to ensure that there are no single points of failure. At least two signals must be simultaneously present in order to launch a weapon. The amazing thing is that not only does MIL-STD-882 not discuss uncommanded launch, it mentions the word “launch” only twice in the entire document.

What MIL-STD-882 does is introduce a culture of safety. It accomplishes this by mandating a “hazard analysis”. All potential hazards must be identified. For each hazard, two parameters are defined: the probability of occurrence and the severity of the consequence if the hazard does occur. Probability of occurrence is set at either “frequent”, “probable”, “occasional”, “remote”, or “improbable”. The severity can be either “catastrophic”, “critical”, “marginal”, or “negligible”, where the severity of “uncommanded launch” is “catastrophic” and of “accidentally banging your head against the missile” is “negligible”. The probability and the severity of a hazard are displayed in a “Risk Assessment Matrix”. Each entry of the matrix is given a colour: Red, orange, yellow, or green. Hazards with high probability and high severity are coloured red while on the other end of the spectrum, hazards with low probability and low severity are coloured green. As a general rule, no system will receive safety certification as long as it has a “red” hazard. But while the definitions are admittedly fuzzy – I have seen people adamantly argue that the probability of a certain hazard was “probable” and not “occasional” – what is important in the safety process is less the location of a hazard in the Risk Assessment Matrix, but, rather, its movement over time within the matrix. Engineers work to find ways in which to “burn down” a hazard by moving its colour away from red and toward green. Sometimes this is accomplished by creating an additional safety mechanism, sometimes via a software change, and sometimes via a mechanical redesign. This is the “culture of safety” that MIL-STD-882 breeds. If people are always thinking about safety, then the system will tend to be safe.

In 2010, it was shown that while mandatory bicycle helmet laws lead to a reduction in bicycle fatalities, they also lead to a reduction in bicycle riding. Social Scientists proposed several reasons for this correlation, including the cost of the helmet and the hassle of wearing one[3]. Stephen Dubner, of “Freakonomics” fame, suggested that this reduction might be a result of helmet laws making biking seem more dangerous. If you need to wear a helmet to ride a bike, the thinking went, perhaps it would be safer to walk or to take a car[4]. Wearing a helmet raises our awareness to the importance of safety. This is what MIL-STD-882 does. And this is what the commandment to make a guard rail does. Yes, there is an all-encompassing commandment to “watch yourselves very well”. The problem is that there are certain places in which we tend to feel more safe, the most prominent of which is our home. When the Torah commands us to build a guard rail specifically “in our own home”, it is warning us that we must not be lulled into a false sense of security that our home is our castle and within its walls we are safe from the elements. It is trying to breed a “halachic culture of safety”.

We segue from physical safety to metaphysical safety[5]. Rabbi J.B. Soloveichik, writing in “Days of Deliverance”, proposes that the commandment to build a guardrail stems from man’s vulnerability, of the body and of the spirit. The awareness of man’s vulnerability must lead him to humility. Rabbi Soloveichik concludes, “Human pride and arrogance disappear the moment man becomes aware of his vulnerability and the suddenness in which his fortune changes. This awareness is cathartic, cleansing; it is an awareness that ennobles man and has a redemptive impact upon him. Humility is the expression of that awareness.”

Shabbat Shalom,

Ari Sacher, Moreshet, 5779

Please daven for a Refu’a Shelema for Yechiel ben Shprintza.

[1]Chamira sakanta me’issura

[2] The current version is MIL-STD-882E.

[3] Two of my children stopped riding bicycles because they were the only ones in their milieu who were forced to wear a helmet and they became the subject of ridicule among their friends.

[4] Mandatory helmet laws for car occupants would, according to this theory, make people much more aware of the danger of driving and would more than likely reduce traffic accidents.

[5] We have still not addressed the reason why a guard rail is not required in a synagogue. Rabbi Eliezer Melamed addresses this problem in “Peninei Halacha”, one of the best modern books of Halacha (available in both English and Hebrew). Rabbi Melamed notes that the commandment to build a guard rail pertains specifically to the roof of a house. Since the roofs of one’s home is used more often than the roof of a synagogue, there is no reason to build a guard rail on the roof of a synagogue. That said, if a synagogue or any other building has a roof that is regularly used, Rabbi Melamed recommends building a guard rail but not making a blessing (“asher kid’shanu b’mitzvotav v’tzivanu la’asot ma’akeh”).

About the Author
Ari Sacher is a Rocket Scientist, and has worked in the design and development of missiles for over thirty years. He has briefed hundreds of US Congressmen on Israeli Missile Defense, including three briefings on Capitol Hill at the invitation of House Majority Leader. Ari is a highly requested speaker, enabling even the layman to understand the "rocket science". Ari has also been a scholar in residence in numerous synagogues in the USA, Canada, UK, South Africa, and Australia. He is a riveting speaker, using his experience in the defense industry to explain the Torah in a way that is simultaneously enlightening and entertaining. Ari came on aliya from the USA in 1982. He studied at Yeshivat Kerem B’Yavneh, and then spent seven years studying at the Technion. Since 2000 he has published a weekly parasha shiur that is read around the world. Ari lives in Moreshet in the Western Galil along with his wife and eight children.
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