The National Society of Professional Engineers maintains a Code of Ethics which opens with the fundamental canon that engineers shall, “Hold paramount the safety, health and welfare of the public.” Structures, tools and other features of the built environment may be designed with what is known as “operational morality,” meaning that care has been taken to ensure that both the construction process and the final product are safe. I have been studying issues of machine morality this summer for a new responsum on halakhah and autonomous vehicles, but for today, my focus is on building safety, specifically during the course of construction.

Parashat Ki Teitze contains the following instruction: “When you build a new house, you shall make a parapet for your roof, so that you do not bring bloodguilt on your house if anyone should fall from it” (Deut. 22:8; JPS trans). As is their habit, the sages of Israel take this single verse both deep and wide. They seek to define its parameters—does it refer only to new construction, or also to purchasing or renting an existing structure? Does it matter if the building is singly or jointly owned? If it is intended for private or public use? How high and how wide must a structure be before this obligation is invoked? Practical answers to all of these questions are found in the early midrash (Sifre Devarim, #229), and Talmud Yerushalmi (Sukkah) and Bavli (Sukkah, BM, BB etc.). If there is any reasonable expectation that a person might use the roof, and any danger that they might fall, then it is the responsibility of the builder, owner, or renter to install a sturdy and effective barrier to protect people from danger.

Our sages go further, comparing this verse to a passage in Exodus (21:33-34) which likewise addresses public safety: “When a man opens a pit, or digs a pit and does not cover it, and an ox or an ass falls into it, the one responsible for the pit must make restitution; he shall pay the price to the owner, but shall keep the dead animal.” With this comparison, the sages have expanded the Torah’s concern from the narrow one of building a parapet to the much broader issue of public safety. In b. Ketubot 41b, Rabbi Natan asks, “What is the source for the rule that a person should not maintain a vicious dog, or keep a shaky ladder at home? It is the verse (from our portion), “so that you do not bring blood-guilt in your house.” The parapet is just an example of the broader principle—both the building and that which it contains must be made as safe as possible. Continue reading →

There is no shortage of specific laws in the book of Deuteronomy—41 mitzvot are found in Parashat Re’eh alone. Yet this book also uses a more general instruction when it offers variants of the expression: “Do what is right and good in the sight of the Lord” (6:18, 12:28, et al). This is the opposite of the warning issued early in the portion, “You shall not act at all as we now act here, every man as he pleases….” The contrast sets up an opposition between individual conscience, which is considered subjective and unreliable, versus divine instruction, which is universal and timeless. Fair enough, but how can one be sure what God deems right, in general terms?

Several later biblical figures are recognized for doing that which is right and good—kings Asa and Hezekiah are praised in this way. There seems to be both a negative and a positive element to such virtuous conduct. On the negative side, they destroyed cultic sites which the prophets of Israel identified as false worship. On the positive side, they sought out the instruction (Torah) and commands (mitzvot) of the Lord. Hezekiah is said to have searched for God with all of his heart, and as a result, to have succeeded. So, doing that which is right and good in the sight of the Lord includes both a negative and a positive mandate—to purge what is deemed evil, and to pursue and practice that which is good. Still, how to know which is which? Continue reading →