Explanation #1: Rashi explains that it speaks with regard to a Din that is not based on (Halachic) reasoning, but rather on the assessment of the Dayan ...

Precedent: ... such as the case in Kesuvos (Daf 85b) of 'The man who declared "My property goes to Tuvya", and along came two Tuvya's who were both relatives and neighbors ...

Precedent (cont.): And the Gemara ruled "Shuda de'Dayni" ' ...

Precedent (cont.): ... meaning that it should be given to whichever one the Dayan thought the donor liked better.

Question #1: Rabeinu Tam queried this however, in that, if it is a matter of S'vara as Rashi explains, why should he not go back and re-Pasken the case

Question #1 (cont.): ... seeing as he will be unlikely to change his original stance?

Introduction to Question #2: Moreover, in the first Perek of Gitin (Daf 14b) in a case of 'Take Manah to P'loni! ... ', where he went and found that P'loni had died, One Beraisa rules that it should be returned to the heirs of the sender, another Beraisa, to the heirs of the recipient ...

Introduction to Question #2: ... and the Gemara concludes that 'Shuda is preferable'.

Question #2: ... and there it is impossible to apply Rashi's interpretation?

Explanation #2: Rabeinu Tam therefore explains 'Shuda de'Daytni' to mean that the Dayan should do whatever he wants, based on the principle 'Hefker Beis-Din Hefker' ...

Meaning of the Word: And 'Shuda' is an expression of 'throwing' - like "Ramah ba'Yam" (Sh'mos 15), which Unklus translates as 'Shadi be'Yama'.

Introduction to Proof: And a proof for Rabeinu Tam lies in the Gemara in Perek 'Mi she'Hayah Nasuy' (Kesuvos, Daf 94b), in the case where two Sh'taros that were written on the same day ...

Introduction to Proof (cont.): ... where both claimants came before Rav Sheishes, who gave one of them the right to claim; and when they later came before Rav Nachman, he handed the right to the other one ...

Introduction to Proof (cont.): ... and where the latter then came before Rav Sheishes, who, in reply to his question as to why he issued his ruling, he replied because the one Sh'tar was written in the morning, the other one in the evening ...

Introduction to Proof (cont.): ... to which Rav Nachman retorted 'Do we live in Yerushalayim, where they write the time?'

Introduction to Proof (concl.): ... Then in reply to Rav Sheishes' question as to why Rav Nachman ruled the way he did, he replied 'Shuda de'Dayna'. And when Rav Sheishes explained that his ruling too, was base on 'Shuda de'Dayna', Rav Nachman pointed out that whereas he (Rav Nachman) was a Dayan, he (Rav Sheishes) was not.

Proof: According to Rabeinu Tam the statement 'I am a Dayan and you are not a Dayan!' makes sense - since to declare 'Hefker Beis-Din Hefker' requires an official Dayan, and Rav Nachman was an official Dayan ...

Proof (cont.): ... but according to Rashi's explanation, that it depends on the judges' assessment, why would that require an official Dayan, seeing as it i obvious that the assesment of Rav Nachman was no better than that of Rav Sheishes?

Question: From where does Rebbi Yehudah learn that he is believed to say that this son is a Ben Gerushah or Chalutzah'? ...

Question (cont.): "Zeh B'ni B'chor" we can understand that he is believed - since it is for the benefit of the child, seeing as on account of it, he will receive a double portion; But on what grounds is he believed to render him Pasul?

Answer #1: When he is believed to say 'Zeh B'ni B'chor' is speaking by a child among his siblings, where the father says that the youngest one is the B'chor, and he is believed ...

Answer #1 (cont.): ... despite the fact that, as a result of his testimony, he establishes the older ones Mamzerim.

Answer #2 (cont.): Rabeinu Eliyahu however, explains that the father is believed based on the Pasuk "Ki es ha'B'chor ben ha'Senu'ah Yakir", and the Gemara explained earlier (on Daf 68a) 'Senu'ah be'Nisu'ehah' - that the marriage was a Chayvei La'avin ...

Answer #2 (concl.): Consequently, "Yakir" pertains to both of them - "Yakir" that he is the B'chor, and "Yakir" that he is the son of a Gerushah or Chalutzah, whose marriage is hated (by Hash-m).

Support: And so Tosfos found in the Yerushalmi (in this Perek, Halachah 6).

Implied Question: [And the reason that it says 'Keshem' (and does not learn the latter from the Pasuk directly) is ...

Answer: ... because according to the simple P'shat, the Pasuk refers more to publicizing the B'chor. Tosfos Yeshanim].

Clarification: Such as where she is unmarried and where most of the town are permitted to marry a Kohen.

Question: Why does the Gemara not ask that, according to the opinion that holds the one who is Machshir, is Machshir even where the majority are Pasul, what is Aba Shaul coming to teach us? ...

Question (cont.): In fact, it ought to have cited Aba Shaul's statement next to the ruling of Raban Gamliel in Kesuvos (there) ...

Precedent: ... like the Gemara will ask shortly according to the opinion that holds 'The one who is Machshir her is also Machshir her daughter'?

Answer: It is not from the Mishnah there that we can learn that Raban Gamliel is Machshir even by Rov Pesulin, but from the Beraisa that it cites there - 'Zu Eidus she'ha'Ishah Kesheirah lah ... ' ...

Answer (cont.): ... which is why it is necessary to mention here the words of Aba Shaul ...

Answer (concl.): On the other hand we learn 'le'Divrei ha'Machshor bah, Machshir be'Bitah' from the Mishnah there ...

proof: ... since the Tana says 'Ra'uhah Medaberes' and 'Haysah Medaberes' - one to be Machshir her and one to be Machshir her daughter, as the Gemara explains there.

Question: Why does the Gemara not ask that we already learned in the Reisha that a Ger may marry a Mamzeres - like it asked earlier.

Answer: The main Kashya there is not that we already learned it earlier - but the Kashya that follows - 'To which case is Rebbi Yehudah referring'?

Question: What is the Gemara asking - bearing in mind that the reason for the Heter is because the Kesheiros are not prohibited from marrying the Pesulim, and not because he is a Ger ...

Question (cont.): ... because we will still say that a Kohen is Asur to marry a Giyores', and 'the one who is Mutar, is Asur' ...

Answer: What the Gemara therefore 'Harei Ger she'Nasa Bas Yisrael?' - whose daughter is permitted to marry both a Kohen and a Mamzer like Rebbi Eliezer ben Ya'akov ...

Support: ... similar to the Gemara's Kashya shortly.

Question: How is their Machlokes implied from the Mishnah?

Refuted Answer: Rashi explains that what it means is that 'All those who are born from an Isur Ervah are Mamzerim and are permitted to intermarry - such as the children of Chayvei Kerisus and those of Chayvei Misos'.

Refutation: This is not correct however, as it is a Dochek.

Authentic Answer: The Ri therefore explains as follows - 'All those who are forbidden to enter the Kahal' - that even if Kidushin does not take effect- such as Chayvei K'risus - 'are permitted to intermarry' ...

Authentic Answer (cont.): In other words - Whoever comes from an Isur where Kidushin is not effective - Chayvei K'risus and Chayvei Misos Beis-Din - are all permitted to intermarry ...

Reason: ... because he holds that a Mamzer results from wherever Kidushin is not effective.

Clarification: This is similar to the Gemara's Kashya above regarding Aba Shaul - 'We already learned this earlier?' ...

Clarification (cont.): ... in which case it should have said there, in connection with Rebbi Yehoshua - 'And Rebbi Yehudah too, concurs with him'?

Question: Why does it need to ask 'Tanina'? Why not rather ask from Rebbi Yehudah on to Rebbi Yehudah - since here he says that there is only a Mamzer from Chayvei Misos Beis-Din ...

Question (cont.): ... whereas in Maseches Yevamos (Daf 49a) he says that "Lo Yegaleh K'naf Aviv" is speaking about a woman whom his father raped, who is a Chayvei La'avin - next to which the Torah writes "Lo Yavo Mamzer" ...

Question (concl.): ... implying that a Mamzer comes even from Chayvei La'avin? ...

Reason: ... bearing in mind that Rebbi Yehudah too Darshens 'S'muchin' in Seifer Devarim.

Answer: Rebbi Yehudah holds there that Eishes Av that the Torah inserts between "Lo Yikach" and "Lo Yegaleh" is superfluous ...

Reason: ... since now that his father's Anusah is forbidden, as the Torah writes "Lo Yegaleh K'naf Aviv", how much more so his wife! ...

Answer (cont.): ... and that being the case, he Pasuk comes to Darshen it and to say that "Lo Yavo Mamzer" pertainsw Davka to "Eishes Aviv" ...

Answer (cont.): ... and to say that from "Lo Yikach" to "Lo Yegaleh" - Eishes Aviv is a Mamzer, but more than that not.