1) WHY DOES "TEFISAH" CIRCUMVENT THE LAW OF RABAH BAR NASAN?
QUESTION: The Mishnah (35b) discusses a case in which the owner of an ox admits that his goring oxen damaged someone else's oxen, but he claims that it was his small Tam ox that did the damage (and thus he agrees to pay only half of the value of the damage). The owner of the gored oxen claims that it was the large Mu'ad ox that did the damage (and thus he demands full compensation). The burden of proof rests on the one who was damaged. Without proof, the owner of the damaged oxen may collect only what the owner of the damaging ox admits that he owes.
The Gemara asks why the owner of the damaged oxen may collect anything. Rabah bar Nasan teaches, "Ta'ano Chitim v'Hodah Lo b'Se'orim Patur." When one person claims that the other person owes him wheat, and the defendant admits that he owes barley but not wheat, he is exempt from payment. Similarly, in the case of the Mishnah in which the owner of the damaged ox claims payment from one ox (the Mu'ad) and the owner admits that he owes payment from a different ox (the Tam), the owner should be exempt from payment altogether! It seems that the Mishnah refutes the ruling of Rabah bar Nasan.
The Gemara answers that the Mishnah refers to a case in which the owner of the damaged ox claims only that it might have been the Mu'ad ox that did the damage. His intention is to claim payment from one of the two oxen, and thus this case is not similar to the case of "Ta'ano Chitim v'Hodah Lo b'Se'orim."
The Gemara asks another question from another case which the Mishnah discusses, in which two oxen damaged two other oxen. The two oxen that did the damage were either a small Tam and a large Tam, or a large Tam and a Mu'ad. One of the damaged animals was large and the other was small. The owner of the oxen that damaged claims that his small Tam damaged the large animal, while either his large Tam or Mu'ad damaged the small animal. The owner of the damaged animals claims that the small Tam damaged his small animal, and the large Tam or Mu'ad damaged the large animal. As in the previous cases, the Mishnah rules "ha'Motzi me'Chaveiro Alav ha'Re'ayah," and thus the owner of the damaged ox must prove his claim if he wants to receive the compensation which he demands.
The Gemara again asks that according to Rabah bar Nasan, the owner of the damaged oxen should not be able to collect anything at all, since he claims the larger amount of damage only from the larger Tam or from the Mu'ad.
The Gemara answers that only if the owner of the damaged oxen does an act of "Tefisah" -- he seizes the damaging oxen -- may he collect the damages which the owner of the damaging oxen admits that he owes. In such a case Rabah bar Nasan's ruling of "Ta'ano Chitim v'Hodah Lo b'Se'orim Patur" does not apply.
Why does an act of Tefisah circumvent Rabah bar Nasan's law?
ANSWER: Tefisah circumvents Rabah bar Nasan's law because the person whose property was damaged collects the damages because of his claim and not because of the admission of the owner of the damaging oxen. Since his entitlement to collect is independent of the other's claims, the case is not similar to a case of "Ta'ano Chitim v'Hodah Lo b'Se'orim."
However, he may collect only the amount which the other owner admits that he owes. This type of Tefisah establishes the claimant as the "Muchzak," the one currently in possession of the item in doubt (in this case, the oxen), so that he may collect what he claims. This takes into account that the owner of the damaging oxen agrees that he owes this money to the owner of the damaged oxen.
The ROSH also explains why the Gemara earlier (35b) does not answer its first question on Rabah bar Nasan (from the first case in the Mishnah) with the answer of Tefisah. The Rosh asserts that Tefisah works only in a case in which the owner of the damaging oxen agrees that the animal that was seized belongs (at least in part) to the owner of the damaged oxen. This is true only in the cases of the Mishnah in which two oxen damaged, such that both oxen are partially owed to the owner of the damaged oxen. (Mordechai Zvi Dicker)

36b----------------------------------------36b

2) DOES REBBI AKIVA AGREE WITH THE LOGIC OF THE GEMARA?
QUESTION: In the Mishnah, Rebbi Meir rules that when a Tam damages multiple animals successively, the owner of the last animal that is damaged has precedence in receiving full compensation. (Since the payment for damages done by a Tam is "mi'Gufo," the amount of money that the owner must pay for the damages by his Tam is limited to the value of the animal.)
The Gemara asks that the Mishnah does not seem to be consistent with the views of either Rebbi Yishmael or Rebbi Akiva. According to Rebbi Yishmael, the damagees are considered creditors who are owed money by the damager, and thus the first payment should be given to the owner of the first ox that was damaged, since he was owed the money first. According to Rebbi Akiva, the damagees are considered partners in the ownership of the damaging ox, and thus the last damagee should not collect first, but rather the money should be split equally among all of the damagees.
The Gemara responds that even Rebbi Yishmael may agree with the Mishnah, because the Mishnah refers to a case in which the owner of the damaged animal seized (Tefisah) the damaging ox immediately in order to collect payment for the damages. After he seized the ox, it went and damaged another animal, and the owner of that damaged animal seized the ox. The ox again ran away and damaged another animal, whose owner seized the ox. This happened numerous times. Each person who seized the ox is responsible for the damage caused to the next animal while he was watching the ox. Each person assumes responsibility for the ox because he has the status of a "Shomer Sachar," a paid guardian, since he benefits from the animal insofar as he may collect the damages from its body.
The Gemara seems to explain the Mishnah only according to the view of Rebbi Yishmael, who maintains that the owner of the damaged ox is comparable to a creditor of the owner of the damaging ox (specifically a Tam). The Gemara implies that the Mishnah is not consistent with the view of Rebbi Akiva, who maintains that the owner of the damaged ox is considered a partner with the owner of the damaging ox. Why, though, does Rebbi Akiva not agree with the Mishnah's ruling in the case that the Gemara describes (each owner of a damaged animal seized the damaging ox)?
ANSWERS:
(a) RASHI (DH Shavuk Masnisin) writes that although Rebbi Akiva indeed may agree with this logic, according to him there is no need for the Mishnah to teach it. It is obvious that the last person whose animal was damaged should receive the money. Since the previous damagees became partial owners of the damaging ox, they became liable for any future damage done by the ox. Only according to Rebbi Yishmael does the Mishnah teach something novel. According to Rebbi Yishmael, the Tefisah renders the previous damagees Shomrei Sachar and thus makes them responsible for any damage done thereafter by the ox.
(b) TOSFOS (DH Kegon) explains that according to Rebbi Akiva, the owner of the damaged animal becomes liable only for half of the damage which the damaging ox does after he seizes it, since he becomes an owner of only half of the ox. Only according to Rebbi Yishmael does the person who seized the ox become liable for any damage subsequently done by the ox, since his seizure of the ox gives him the status of a Shomer Sachar.
Tosfos' logic seems difficult to understand. According to Rebbi Yishmael, the person who seizes the ox becomes a Shomer Sachar for the entire ox because half of its value is owed to him, and he is holding the ox in order to collect his damages. Why does the same logic not apply to Rebbi Akiva's view? According to Rebbi Akiva, the person who seizes the ox also should be considered a Shomer Sachar for the entire ox since he seized it in order to claim half of its body.
The AYELES HA'SHACHAR answers that according to Rebbi Akiva (who maintains that the damagee owns half of the ox), when the damagee seizes the ox, he seizes only the half which belongs to him. Although physically he takes possession of the entire ox, his intent is to seize only the half that is his. Accordingly, his seizure of half of the ox does not make him a Shomer Sachar for the other half, since he did not intend to grab it for his own purposes. The liability for damage that it causes remains split between the owner of the ox and the damagee who seized it.
In contrast, according to Rebbi Yishmael the ox itself belongs only to its original owner, while half of its value happens to be owed to the damagee. In such a case, the owner of the damaged ox intends to seize the entire animal (none of which is his) in order to collect from it half of its value. This makes him a Shomer Sachar for the entire animal and liable for all damages that it does. (Mordechai Zvi Dicker)
3) RAV YOSEF, THE "GABAI TZEDAKAH"
QUESTION: The Gemara relates that a person was harmed by someone else and was owed half a Zuz as compensation. When the damagee heard that he would receive only half a Zuz, he was not interested in the money and said that it should be given to the poor. He then changed his mind and decided to use the money to heal himself. Rav Yosef told him that he may not do so, since the money is considered as though it had already been acquired by the poor. Although there were no poor people in the area, Rav Yosef -- in his capacity as Gabai Tzedakah -- acquired the money on behalf of the poor people elsewhere.
TOSFOS (DH Yad Aniyim) and others ask why the Gemara needs to add that Rav Yosef's hand is like the hand of the poor. Why is that fact essential to the ruling of the Gemara? The damagee already promised to give the money to Tzedakah, and thus he cannot retract his promise. The Gemara in Rosh Hashanah (6a) teaches that when one says that he will give money to Tzedakah, his statement has the status of a vow which he must fulfill. What difference does it make that Rav Yosef was a Gabai Tzedakah?
ANSWERS:
(a) TOSFOS answers that the money owed is a "Davar she'Lo Ba l'Olam," an object which has not yet come into the world. Just as a person cannot be Makdish a Davar she'Lo Ba l'Olam, his promise to give a Davar she'Lo Ba l'Olam to Tzedakah is not binding. He would have been obligated to keep his word only if he would have made a general promise to give half a Zuz to Tzedakah, not a specific half Zuz that at this moment is considered a Davar she'Lo Ba l'Olam.
(b) Tosfos quotes RABEINU CHANANEL who says that the damagee did not retract his desire to give the money to Tzedakah. He merely wanted to borrow the money and afterwards pay other money back to Tzedakah. Such a loan is permissible as long as the money has not yet reached the hands of the Gabai Tzedakah or the poor people themselves. Rav Yosef claimed that since he was a Gabai Tzedakah, the money had already reached the hands of the Gabai and it cannot be borrowed anymore. Although Rav Yosef had not yet physically received the money, the rights to the money had been given to him through "Ma'amad Sheloshtan." Since the damagee said he would give the money to Tzedakah in the presence of the person who owed him the money and the Gabai Tzedakah, the Gabai Tzedakah (Rav Yosef) is considered to have already acquired the money. (Mordechai Zvi Dicker)