Bava Kamma 21

It begins with negligence and ends with an accident.

Today’s daf raises the following questions about liability: How negligent must a person be to be held liable for an accident? And how connected to the accident must the act of negligence be? Let’s start with the mishnah:

The owner of a dog or a goat that jumps from the top of a roof and breaks vessels must pay full damages, because they are considered forewarned …

The Gemara asks about a reasonable inference: If the animal fell rather than jumped, is the owner still liable? Another tannaitic source suggests the owner is not liable for animals that accidentally fall off the roof (less predictable than jumping), but this raises the question:

What about the principle, “It begins with negligence and ends with an accident”?

In other words, shouldn’t we hold someone responsible for an accident that occurred because of something negligent they did? But just how negligent? And how closely connected to the accident must that negligence be?

The sugya offers a flurry of case studies in which negligence of some kind leads to an accident that damages property, including: an animal that is negligently let up onto a roof and falls off and damages vessels (liability depends on the proximity of the vessels to the roof), an animal that is negligently allowed up on an unstable wall from which it accidentally falls and damages vessels (this case is dismissed since the expected damage is not from an animal falling but from loose bricks falling, which didn’t happen), an animal is negligently allowed to climb on a narrow wall from which it falls and causes damage (the owner is liable since the fall is predictable) and an animal that behaves in some unexpected way that causes damage (the owner is not liable because this behavior is considered unpredictable).

We can gather from all these examples some important notions about the concept of negligence, and how far it extends. A person can be held liable for an accident if that accident was caused by their negligence and reasonably predictable. When the act of negligence is not directly connected to the accident, on the other hand, the owner is not held liable. 

In fact (spoiler alert for tomorrow’s daf!), the Gemara asks about a specific case that is out of the ordinary: 

Isn’t there a beraita that teaches: “The owner of a dog or a goat who leaps, whether from top to bottom or bottom to top, is exempt from paying damages”?! 

Rav Pappa interpreted: Their movements were changed. The dog was leaping and the goat was climbing. 

If that is so, why are the owners exempt? They are exempt from paying the full damage; they are liable to pay half the damage.


Regarding this exchange, the talmudic commentators Tosafot and Rosh both explain that the owner only pays half because the damage caused was in a different category than the damage expected from the negligence. The negligence, in this case, was in the category of regel (trampling), but the accident that resulted was one of keren (goring). (It falls into the category of keren because it is an unexpected act, a debated but ultimately defining trait of the category).

While the accident does cause damage — and therefore the owner does not get off scot free — one would not have predicted it as easily and would have more likely expected other damage as a consequence. Thus, the damage must be accounted for, but it is not because of the concept presented here that, “It begins with negligence and ends with an accident.” That principle, according to this sugya, is reserved for a case where one can draw a straight line from the act of negligence to the accident that occurred.

Read all of Bava Kamma 20 on Sefaria.

This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on November 23rd, 2023. If you are interested in receiving the newsletter, sign up here.

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