Question: Seeing as he did not accept the Sh'mirah, why is it not obvious that a Tam pays half damage and a Mu'ad, in full?

answer: Because we might have thought that, even though he does not undertake the Sh'mirah of other Nizakin, he automatically accepts the damages of the Nizak himself.

Observation: It could have established the case of Rav Yosef where the Chatzer was not designated to either of them for oxen, and for one of them for fruit.

Explanation (Text) #1: Rabeinu Tam has the text 'Lo la'Zeh ve'Lo la'Zeh li'Shevarim', because regarding Shein it is the Chatzer of the Nizak, when it damages fruit, but regarding oxen it is a case of Keren bi'Reshus ha'Rabim, seeing as they did not have permission to enter it.

Rejection of Explanation #3: Nor do we have the text that is written in the Sefarim 'la'Zeh ve'la'Zeh li'Shevarim', because then regarding Shein, it should not have considered it the Chatzer of the Nizak, since both parties have permission to bring in their oxen, as is evident above.

Rejection of Explanation #4: Neither does the Gemara want to establish it where both have permission to bring in fruit, but not their oxen ...

Reason #1: ... because that would be not like Rebbi Zeira.

Reason #2: Moreover, the Lashon does not imply that (See Tosfos Daf 16. DH 'Kulah')..

Clarification: It is fine according to Shmuel, who establishes the Reisha like Rebbi Tarfon and the Seifa like the Rabbanan, and we need the Seifa to preclude from Rebbi Tarfon ...

Clarification (cont.): ... but according to Ravina it is entirely unnecessary, because regarding Shein, which is the Chatzer of the Nizak, we already know from 'Kol she'Hu R'shus le'Nizak', whereas the Din of 'Keren bi'Reshus ha'Rabim' we know from 'Chatzar ha'Shutfin ve'ha'Bik'ah'.

Explanation #1: Rashi explains that they damaged each other, and one now assesses the value of the damage, and whoever caused more damage must pay the difference.

Question: 'Parah she'Hizikah Talis' can only be speaking in the Chatzer of the Nizak, either where it damaged with intent, and it is 'Keren', or as it was walking, and it is 'Regel'.

Question (cont.): Whereas 'Talis she'Hizikah Parah' must be speaking in the R'shus ha'Rabim, since it is 'Bor'?

Refuted Answer #1: It is impossible to establish 'Parah she'Hizikah Talis' too, in the R'shus ha'Rabim, on account of Keren ...

Refutation: ... because if so, the owner of the cow would be Patur, as the Gemara says later, in the second Perek (on Daf 20.), where it states that wherever the Nizak is Meshuneh (unusual), and the Mazik then damages the Nizak in an unusual way, the owner is Patur'.

Suggested Explanation: And even if we explain that what happened was the cow damaged the Talis in the Chatar ha'Nizak and the Talis then damaged the cow in the R'shus ha'Rabim ...

Question: ... that is a Mishnah later in Perek ha'Meni'ach (daf 33.) - 'Two Tam oxen that damaged each other, the one that caused more damage pays half the difference, and if they are Mu'adin, then he pays the difference in full?

Answer: The Mishnah states the Din here and elaborates there.

Explanation #2: Rabeinu Tam therefore explains that the Tana means 'either or' ...

Precedent: ... like 'Chalatz, veAsah Ma'amar ve'Nasan Get' in Yevamos (Daf 50.).

Refuted Chidush: He is not coming to teach us that we do not say that he cannot take the entire Talis to pay for the damage ...

Refutation #1: Seeing as the Talis is a 'Bor' and does not therefore pay mi'Gufo.

Refutation #2: Furthermore, we learn that too from the Mishnah in 'ha'Meni'ach'.

Explanation #3: So Rabeinu Tam explains that what the Beraisa is coming to teach us not like Rebbi Akiva, who says later in 'ha'Meni'ach' (Ibid.) that 'The entire Shor goes to the Nizak', but like Rebbi Yishmael, who says that we assess it, and it is talking about 'Keren' (See Maharam).

Explanation #3 (cont.): ... and 'Talis be'Parah' teaches us that one cannot claim from the Yesomim ...

Explanation #3 (cont.): Since we would otherwise have thought that one can in fact claim from them, even though Metalt'lin of Yesomim are not Meshubad.

Reason: ... because when the Torah says that he pays from his pocket, it is in order to benefit the Nizak, in case the Mazik is not worth as much as the damage ....

Reason (cont.): ... whereas regarding Yesomim, where if one pays from one's pocket, it will be a loss to the Nizak, seeing as the Metalt'lin of Yesomim are not Meshubad ...

Reason (cont.): But if one were to pay from the body of the Mazik, he could claim even from the Yesomim, because it is as if he already claimed the ox whilst it was still alive ...

Conclusion: ...thus giving us reason to think that they must pay from the body of the Mazik.

Refuted Text: We do not have the text 'Parah she'Hizikah T'leh' ...

Reason: ... because if so, the Tana ought to have said 'Oxen that gored each other', as we learn later in 'ha'Meni'ach' (Ibid.).

Justifying the Current Text: And it is the way of the Gemara to mention a cow and a Talis, as we find later (on Daf 94:) 'If their father left them a cow and a Talis'.

Clarification: This is La'av Davka, since more than half is subject to Ona'ah, as is implied in Perek ha'Zahav (Bava Metzi'a, Daf 57:) .

Clarification (cont.): Only what it means is more than Metalt'lin.

Change of Text: We do not have the text 'Sh'taros', since they cannot be acquired with money, only with Mesirah and with a Sh'tar.

Change of Tex (cont.): And even if one acquire them with Chalipin needs looking into.

Rashi: And Rashi comments that he does not know where it says that one can acquire Sh'taros with money.

Question: According to Rav and Shmuel, who hold in Perek Get Pashut (Bava Basra, Daf 175.) that Shibud is not d'Oraysa and that one cannot therefore claim an oral loan from the heirs, one cannot even claim Nechasim she'Yesh lahem Acharayus (Karka)?

Answer: (According to them) it speaks where they have already been to Beis-Din.

Explanation #1: Rashi explains the Kashya to mean - 'But do we not Pasken that the creditor may come and claim?

Question: If Nizakin are like a Milveh bi'Shetar, the Gemara ought not to have said 'Sh'ma Minah ... ', but rather 'Does the Mishnah not say that someone who lends his friend with a Sh'tar, may claim from Nechasim Meshubadim?

Question (cont.): ... whereas if they are considered a Milveh al Peh, then why does it say "Sh'ma minah Ein Beis-Din Govin lo meihen?' since it is obvious that one cannot claim, as we learned in the Mishnah (in Bava Basra, 175.) 'Someone who lends his friend with witnesses, can (only) claim from Nechasim B'nei Chorin'?

Refuted Answer: And if the Gemara is coming to teach us - "Sh'ma minah, de'Ein Govin lo meihen", and it is like a Milveh al Peh, even though Nezikin is a Milveh ha'Kesuvah ba'Torah, in which case it poses a Kashya on the opinion in Erchin (Daf 6:) that holds 'Milveh ha'Kesuvah ba'Torah, ki'Chesuvah bi'Sh'etar Damya' ...

Refutation: ... why does the Gemara then say '(Sh'ma minah) Lavah u'Machar Nechasav ... ', it should rather have said 'Sh'ma minah Milveh ha'Kesuvah ba'Torah, La'av ki'Chesuvah bi'Sh'etar Damya'?

Explanation #2: Rabeinu Tam therefore explains "Sh'ma minah Lavah u'Machar Nechasav, Ein Beis-Din Govin lo meihen' - min ha'Torah, de'Shibuda La'av d'Oraysa'.

Explanation #2 (cont.): And that explains why one cannot claim from Nezikin either, seeing as it is Davka by a Milveh bi'Shetar that the Rabbanan instituted to claim from Meshubadim, on account of Ne'ilas Deles.

Explanation #2 (concl.): Because if Shibud was d'Oraysa, and that one cannot claim by a Milveh al Peh in order to protect the purchasers, then one can ask why one cannot claim by Nezikin, where there is no need to protect the purchasers?

Refuted Answer: ... and it is not comparable to a Mileh al Peh ...

Refutation: ... seeing as someone who lends, lends discreetly, which cannot be said about a Mazik, and where there is a Kol (people are aware of the damage).

Conclusion: And this poses a Kashya on the opinion that holds 'Shibuda d'Oraysa in Perek Get Pashut (Bava Basra, Daf 175:).

Clarification: Rashi establishes it with regard to the Din of K'nasos.

Implied Question: Even though, according to the opinion that the Tana learns 'Shor' because of Regel and 'Mav'eh', because of Shein, the Mishnah is not speaking about K'nasos?

Answer: ... The Tana nevertheless hints in the Seifa even at things that he does not mention in the Reisha.

Support: And so indeed, the Gemara will shortly explain that 'al-Pi Eidim' - comes to exclude Modeh bi'Kenas ve'Achar-kach Ba'u Eidim'.

Clarification: It is not necessary to teach us the Din where he admits to a K'nas and Eidim do not come at all ...

Source: ... since that is a Mishnah in 'Merubeh' (later, Daf 74:)

Implied Question: Nor can one answer that the Mishnah makes the statement here and explains it later ...

Answer: ... seeing as it says no more there than it does here.