A fire that could not have been anticipated and/or prevented by reasonable care is an oness (extenuating circumstance), for which even a shomer sachar (paid watchman) like Shimon is exempt from paying.[1] There is a major machloket with regard to a case in which a shomer was negligent in guarding an object, but the damage eventually came about through an oness. The topic is called techilato b’pshiya v’sofo b’oness. The halacha is that in a situation of techilato b’pshiya v’sofo b’oness, the shomer is obligated to pay[2] provided that there is a chance that the damage, unexpected as its manner ended up being, would not have happened had the shomer not been negligent.[3]
In our case, the fire does not seem to have been related to the overloading of the trailer. However, had the extra items that were improperly placed in the trailer been placed in the truck, as they should have been, they would not have been destroyed, as the fire did not get into the truck. The simple rules of techilato b’pshiya v’sofo b’oness would thus seem to obligate Shimon.
It is possible, however, that the halachic logic of obligating techilato b’pshiya v’sofo b’oness affects the degree of the obligation. Why should one pay for damages that were related to the p’shiya only by chance and not in a predictable manner? The two main possible answers are as follows. 1) When one is negligent, he becomes conditionally obligated financially. He is off the hook if no damage results or if it occurs in a manner totally unrelated to the p’shiya. However, when something he is marginally responsible for occurs, the p’shiya that had previously obligated him comes into play. 2) An oness that happens in the aftermath of a p’shiya is a continuation of the p’shiya, which obligates him. Thus, at the time of the damage, he is obligated by his p’shiya.
The practical difference between these two explanations could be in a case like ours, in which the potential damage resulting from the p’shiya would have been relatively limited in comparison to the damage caused by the eventual oness. According to possibility #1, the monetary obligation should not exceed that which should have resulted from the p’shiya, which, in our case, is minimal. According to #2, the eventual damage should be considered a result of the p’shiya, and it obligates Shimon fully.
Tosafot[4] posits that if one did a p’shiya in which he would have shared responsibility with another and then an oness happened that related to him alone, he pays no more than he would have for the p’shiya. Rav Soloveitchik[5] and Rav Y.M. Charlop[6] explain Tosafot’s position as being based on possibility #1. In other words, the obligation stems directly from the p’shiya and therefore cannot exceed the financial liability that the normal aftermath of the p’shiya would have brought about. We have not found anyone who explicitly disagrees with Tosafot. Yet, there are indications that others feel that possibility #2 is correct. R. Akiva Eiger[7] understands that Abayei and Rava dispute which approach is correct and that Rava, according to whom we pasken, posits #2. The Netivot HaMishpat[8] assumes that we estimate the damaged object’s value according to the time of damage, not that of the p’shiya, which also might be an indication that he views the matter like #2. [Further deliberation and application in this complicated ruling is beyond our scope.]