Is a person liable for damage caused by their property? For example, if I direct an autonomous vehicle to drive me to the store, and the car runs over property or injures or even kills an animal or a person, is it my fault? Can it be partially my fault? How should we decide? Such questions are a focus of my new responsum on artificial intelligence, which is still in draft form.
As with all questions of technology, a starting point is to look for precedents, and it happens that most of them are linked to our portion, Parashat Mishpatim. This Torah portion is the basis of Hilkhot Nezikin, the laws of damage. In Jewish law, a distinction is made between damage a person causes with their own body (נזקי גופו), and damage that is caused by their property (נזקי ממונו). Our portion discusses some cases of direct damage, as when one person assaults another or steals their property. However it also considers cases when a person is not careful with their property. Perhaps they create a hazard such as a pit on their property or a roof that lacks a parapet. Maybe they set a fire that burned out of control and damaged a neighbor’s crops. Or perhaps they own animals which cause damage. How to determine liability?
One of the major considerations in Jewish law is reasonable expectation. If an animal is normally expected to be docile, then suddenly goes on a rampage, the owner has limited liability. But if the animal is already known to act violently, then the owner is responsible to take precautions, to guard their property. If such a “warned” animal (mu’ad) causes damage, then the owner is generally fully liable.
Still, the sages were aware of more complicated cases. Consider for example, a chicken that is hopping around, causing mayhem, just as it is expected to do. In this case, the damage is made worse by a string that has gotten caught on the chicken’s foot. The Talmud wants to know who owns the chicken, who owns the string, and whose fault it is that the chicken got caught up in this mess. Generally, if no person caused the chicken to get tied up, then the owner has limited liability (half-damage) for property destroyed by the string, but if he left the string out or even attached it, then the owner is fully liable for damage done by the chicken. But which owner—of the bird or of the string? It depends whose fault it is that the bird got tied up. When damage is done, blame must be assigned. This is all well and good in theoretical cases, but what about reality?
When it comes to autonomous vehicles, it is very difficult to assign blame for damage. Let’s say that such a vehicle fails to yield to another car, colliding and causing damage to the second car. Who is responsible for this damage? The passenger? The car dealership? The manufacturer? Or the original programmer of the software? On the one hand you might say that whoever “tied the string to leg of the chicken” is responsible, but in reality, the presence of so many potential contributors to the damage might exempt them all. And yet someone must be responsible. Jewish law also considers indirect damages—sometimes we are responsible for damage that we caused indirectly. This is called dina d’garmei. But the link between doer and damage needs to be pretty clear and immediate for the owner to be held liable. Can we say the same for a programmer whose algorithm malfunctions in one of many millions of units months or years later?
I don’t know the answer yet. It seems that perhaps the person closest to the action should be at least partially responsible. And if they have reason to blame another person for creating a defective system, then they may be able to sue them in turn for restitution. We are entering into uncharted territory, with machines acting on our behalf, often with good consequences, but sometimes with calamitous effects. Parashat Mishpatim suggests that all people who design or use technology must consider the hazards of their property and take responsibility even for actions that appear beyond their control. Such an expansive theory of responsibility for the acts of machines will remind us to regulate our property more carefully, following the wise precedents of our ancestors.
(לג) וְכִי יִפְתַּח אִישׁ בּוֹר אוֹ כִּי יִכְרֶה אִישׁ בֹּר וְלֹא יְכַסֶּנּוּ וְנָפַל שָׁמָּה שּׁוֹר אוֹ חֲמוֹר: (לד) בַּעַל הַבּוֹר יְשַׁלֵּם כֶּסֶף יָשִׁיב לִבְעָלָיו וְהַמֵּת יִהְיֶה לּוֹ:
בבלי בבא קמא דף יט עמוד ב
התרנגולין מועדין להלך כדרכן ולשבר וכו’. אמר רב הונא: לא שנו אלא שנקשר מאליו, אבל קשרו אדם – חייב. נקשר מאליו מאן חייב? אילימא בעל הדליל, היכי דמי? אי דאצנעיה, אנוס הוא! ואי לא אצנעיה, פושע הוא! אלא חייב בעל תרנגול, מאי שנא כוליה נזק דלא? דכתיב: כי יפתח איש בור, ולא שור בור, חצי נזק נמי איש בור ולא שור בור! אלא, מתני’ בדאדייה אדויי, וכי אתמר דרב הונא – בעלמא אתמר: דליל הפקר, אמר רב הונא: נקשר מאליו – פטור, קשרו אדם – חייב. משום מאי חייב? אמר רב הונא בר מנוח: משום בורו המתגלגל ברגלי אדם וברגלי בהמה.