The limitation of the mego (מִיגוֹ) TB Baba Metzia 116

The Talmudic law concept mego (מִיגוֹ) is a reason that a claim that would otherwise be rejected by a Jewish civil court should be accepted based on the fact that the litigant could have prevailed in the case based on a different claim were he disposed to lie. Even though the last sugiyah in the ninth chapter of our massekhet on  TB Baba Metzia 116 never explicitly uses the term mego, the analysis of two cases clarifies the extent a mego  is effective.

Ҥ The Gemara relates: There was a certain man who took as collateral a slaughtering knife from another. He came before Abaye to ask him what to do. Abaye said to him: Go and return it, as it is a vessel used in the preparation of food, and it is therefore forbidden to take as collateral, and go stand in judgment, i.e., litigate with the debtor in court, concerning how much money he owes you. Rava said: He does not have to stand in judgment for this. Since the knife is in his possession, he can claim the amount of the debt up to its value.

“The Gemara asks: And does Abaye not accept that reasoning, that one who seized an item belonging to a debtor may claim the sum owed to him up to the value of the item? In what way is it different from the incident involving those goats that ate peeled barley [ḥushla] in Neharde’a, and the owner of the peeled barley came and seized the goats and claimed that their owner was indebted to him for a large amount, and Shmuel’s father, who acted as a judge in this case, said that he can claim a sum up to their value?

“The Gemara answers that there is a difference between the two cases: There, a goat is an item that is not usually lent out or rented. Consequently, the one who possesses them has a presumptive right of ownership upon which he can base his claim. Conversely, here, the slaughtering knife is an item that is usually lent out or rented. Therefore, he is not deemed credible without proof that it is his merely by virtue of its being in his possession. The Gemara supports this distinction: As Rav Huna bar Avin sent the following ruling: In a case of items that are usually lent out or rented, and one in possession of them says: They were acquired by me, he is not deemed credible by this claim alone. He must provide further proof, as he might have borrowed or rented them.

“The Gemara asks: And does Rava not accept this reasoning? But didn’t Rava himself remove scissors used for wool and a scroll of aggada from the possession of orphans as items that are usually lent out or rented? The Gemara answers: Rava could have said to you: With regard to this slaughtering knife too, since it is likely to be damaged, people are particular and do not lend it out. Therefore, it is not considered an item that is typically lent out, and the one in possession of it can claim the money owed to him up to the value of the knife.” (Sefaria.org translation)

This analysis of the two cases clarifies the extent a mego is effective. Mego only works when the argument is plausible. For example people didn’t lend out goats. If one has somebody else’s goals, he could claim he bought them. Since the owner of the field didn’t use this plausible possibility, the mego works. The same argument works for Rava when it comes to the shokhet’s knife.