Bava Kamma 5B

לכתוב רחמנא תרתי, ותיתי אידך מינייהו; הדר אמר: חדא מתרתי לא אתי.

Let God write only two of the primary categories and derive the other categories from them. Then the tanna says: It is not possible to derive one category from two other categories, as each category has its own unique characteristics, which prevent the derivation of a new category even from a combination of two categories.

אמר רבא: וכולהו כי שדית בור בינייהו ⁠– אתיא כולהו במה הצד, לבר מקרן; משום דאיכא למיפרך, מה לכולהו שכן מועדין מתחילתן.

Rava said: And with regard to all of the primary categories in the Mishnah, when you cast the primary category of Pit among them, all of the rest of them can then be derived through an analogy based on the common factor of two categories. This is the case with all of the categories except for Goring, due to the fact that there is room to refute the analogy to teach the halakha of Goring with the following contention: What is notable about all of the other categories? They are notable in that they are forewarned from their outset. Since it is the typical manner of the animal to trample and eat, and the typical manner of fire to burn, and the typical manner of a pit to serve as an obstacle, the owner is always forewarned with regard to safeguarding against damage and is liable to pay full damages for his failure to prevent the damage even the first time. With regard to Goring, the animal is innocuous for the first 3 instances of damage and only after that is the animal forewarned, rendering its owner liable to pay full damages.

ולמאן דאמר: אדרבה, קרן עדיפא ⁠– שכוונתו להזיק; אפילו קרן נמי אתיא.

And according to the one who says: On the contrary, Goring is superior in the sense that one’s liability in a case of Goring is more apparent, as the objective of the ox’s action is to cause damage, even Goring can be derived from the common factor of two sources.