The famous first Mishna of Masekhet Bava Kama delineates the basic categories of nizkei mamon – damages caused by one’s possessions for which he is liable to compensate the victim. These categories are: 1) keren – damages caused when one’s animal acts in an uncharacteristically violent manner; 2) shein ve-regel – damages caused when one’s animal acts in a normal fashion, such as by eating or trampling upon people’s property; 3) eish – damages caused when an ordinary gust of wind blows a person’s object that had been left exposed, such as fire that spreads; 4) bor – damages caused when one places a hazard in a public place, such as by digging a ditch. All these situations of liability are briefly discussed by the Torah, in Parashat Mishpatim.
The Gemara (Bava Kama 5b) observes that the Torah did not, at first glance, need to specify all these cases of damages. If the Torah had introduced only the liability for bor and one of the other three, we could have then inferred the remaining two through logical deduction. (See Rashi s.v. ve-khulhu for an explanation of this process of logical deduction.) However, the Torah found it necessary to enumerate all four cases of damages because each has a unique halakhic feature that it does not share with the others. Namely, in a case of keren, the owner needs to pay only half the value of the damages, unless the animal has established a pattern of violent behavior. In a case of shein ve-regel, the owner is not liable if the damages occurred in a public area (as people should not leave their belongings unattended in public places). Eish liability does not extend to tamun – objects that were concealed when they damaged. And liability for bor is incurred only for damages caused to animals, but not to damages caused to people or utensils. Accordingly, the Torah needed to specify each category of damages, because each has a unique halakhic feature. Otherwise, there would not have been any need to establish all four categories, as we could have inferred the final two categories through the process of logical deduction. This is indicated already by the opening Mishna of Masekhet Bava Kama, which notes the “tzad ha-shaveh” – the common denominator – between the four categories of nezikin. This observation suggests that in principle, the Torah did not need to specify all four categories, as at least some could have been inferred through logical deduction, based on their shared characteristics.
Tosefot (2a, s.v. ve-lo) note that the Mishna and Gemara work off the assumption that “oneshim mamon min ha-din” – we can impose financial liability based on logical deduction. When it comes to court-administered punishment – malkot (whipping) and execution – there is a fundamental rule that “ein oneshim min ha-din” – punishment can be administered only if the Torah directly forbids the prohibited act in question. Although Chazal were authorized to apply a Torah prohibition beyond its immediate context through the various logical tools at their disposal (such as “kal va-chomer”), Beit Din does not punish violators who transgress a law established through logical extension. Tosefot here observe that the Mishna appears to distinguish in this regard between corporal punishment and execution, on the one hand, and financial liability, on the other. Apparently, while Beit Din cannot physically punish violators who transgress a law established through logical deduction, financial liability can be imposed on the basis of logical deduction.
Tosefot suggest that this matter is subject to a debate among the Tanna’im. Whereas the opening Mishna of Bava Kama, as discussed, seems to maintain that financial liability can be established on the basis of logical deduction, the Mekhilta states, “Ein oneshin mamon min ha-din” – ruling out the possibility of forcing a defendant to pay based on a law established through logical deduction. The Mekhilta infers this principle from the Torah’s formulation in introducing the liability for bor: “If a person opens a pit, or if a person digs a pit…” (21:33). At first glance, the Mekhilta comments, there seems to be no reason for the Torah to mention both scenarios – where one opens a ditch that had earlier been dug and then covered, and where one digs a new ditch. The fact that the Torah found it necessary to mention both situations, the Mekhilta comments, proves that we cannot apply financial liabilities from one case to another based on logical reasoning. The Torah needed to specify bor liability in both these cases because we cannot extend liability on our own.
Tosefot assert that the Mishna, which clearly does not accept the Mekhilta’s position, likely follows a different explanation for why the Torah specifies both instances of bor. The Gemara (Bava Kama 49b) understands the extra phrase “or if a person digs a pit” as alluding to the fact that in a case of bor, one bears liability only for creating the hazard, and not because the damage was caused by his property. As such, liability is imposed when one creates a hazard in a public property, despite the fact that the person does not own the ditch or obstacle. The Gemara clearly does not accept the Mekhilta’s reading of the verse, and Tosefot therefore conclude that different views exist with regard to the rule of “ein oneshin mamon min ha-din.”