Pesak: Even though [normally] we do not learn the Halachah from a Mishnah or Beraisa (Rosh, and it seems this is Tosfos' intent), here the Halachah follows him.

Reason #1: The Stam Mishnah in Kidushin (66b) seems primary.

Such a case is called clearcut Halachah in Bava Kama (102a) and Avodah Zarah (7b) regarding "whoever retracts, he has the lower hand."

Proof #1 (that the Halachah does not follow R. Akiva): Above (14a) we said "obviously, Bnei Chayavei Lavin are Kosher!"

Proof #2: Above (23a), Rav Papa said "presumably, since Kidushin Tofsin in Chayavei Lavin..."

Proof #3: Above (45a), we rule that if a Nochri or slave has Bi'ah with a Bas Yisrael, the child is Kosher.

Proof #4: Several Amora'im discuss the Tzarah of Machazir Gerushaso. According to R. Akiva, she cannot have a Tzarah, for Kidushin does not take effect with Chayavei Lavin!

Proof #1 (that the Halachah does not follow R. Yehoshua): We said above (45b) "both of them learned from Eshes Av." (One opinion holds that the child of a Bas Yisrael from a Nochri or slave is a Mamzer, just like from Eshes Av, for in both cases Kidushin does not take effect. The other disagrees; a Nochri and slave are unlike Eshes Av, for they cannot be Mekadesh anyone);

All agree that Chayavei Kerisos are like Eshes Av (they can be Mekadesh others. Therefore, the child is a Mamzer.)

Proof #2: Above (37a), R. Eliezer ben Yakov, whom the Halachah [always] follows, said that the child [of Safek Eshes Ach] is not a Safek Mamzer;

Inference: The child of Vadai Eshes Ach (which has Kares without Misas Beis Din) is a Mamzer.

Proof #3: Above (40b), Rav Tuvi bar Kisna said that if one has Bi'ah with the Tzarah of his Chalutzah, the child is a Mamzer;

Even R. Yochanan argues only because he holds that the Tzarah is forbidden only with a Lav. (If he agreed that there is Kares, he would agree that the child is a Mamzer.)

Alternate text: Some correct the text to say "R. Yehudah" in place of R. Yehoshua, for in Kidushin (74b), regarding "all who are forbidden to marry into Kahal [Yisrael] may marry each other", R. Yehudah forbids;

The Gemara explains that R. Yehudah holds that a Mamzer from a sister is not a Mamzer. Only from Eshes Ish [or other Chayavei Misas Beis Din is a Mamzer].

The Gemara asks that this was already taught in our Mishnah here! (This shows that also here, the text says R. Yehudah.)

Rebuttal #1: How could Ben Azai support R. Yehudah [from the scroll of lineage]? Ben Azai was much older than him, for he was a Talmid Chaver of R. Akiva, like it says in Bava Basra (158b);

R. Yehudah was one of the latter Talmidim of R. Akiva (after his 24,000 Talmidim died).

Rebuttal #2: R. Yehudah holds like R. Akiva, that Mamzerim result from Chayavei Lavin, like I explained above (47a) regarding the man who came in front of R. Yehudah. (R. Yehudah implied that if he were believed about his children, i.e. that they were born to a Bas Yisrael from a Nochri, they would be forbidden);

This is like it says in Sanhedrin 53b.

Conclusion: Rather, surely the text says R. Yehoshua. The Gemara asked [in Kidushin] that this was already taught in our Mishnah, for if he held like R. Yehoshua, it should have said "also R. Yehudah says like him."

Observation: The Gemara asked that this was already taught. It could have asked better, that we cannot say that R. Yehudah holds that there is no Mamzer from a sister, since he establishes the verse ["v'Lo Yegaleh Kenaf Aviv"] to discuss Anusas Aviv, and he holds like R. Akiva, that there is a Mamzer from Chayavei Lavin.

Question: Why didn't it say Stam "Chayavei Misas Beis Din"?

Suggestion: The episode happened to be with an Eshes Ish.

Rejection: If so, what is the source that it is like R. Yehoshua?! (Perhaps Chayavei Kerisos, or even Chayavei Lavin, make a Mamzer, just the episode was with an Eshes Ish!)

Answer: It mentioned Eshes Ish for a Chidush. [The child is a Mamzer] even though it is more lenient than other Chayavei Misas Beis Din, for its Misah is Chenek (strangling; we hold that this is the lightest Misas Beis Din), and there is a Heter for it in the life of the one who forbids her (through a Get).

Question: The verse "Lo Yavo Petzu'a Daka" interrupts between them!

Answer: Since a Petzu'a Daka (and the other castrated men mentioned in the verse) cannot beget children, so Mamzer does not apply, this is not considered an interruption.

Rashi's opinion: The text says "the Torah should have written Lo Yigaleh";

Rhetorical question: From Lo Yigaleh alone, we would learn that from a Mamzer results from Chayavei Kerisos according to Rabanan, or from Chayavei Lavin according to R. Yehudah. Why do we need "Lo Yikach Ish Es Eshes Aviv"?

Answer: Since the Torah wrote this, this teaches that Lo Yavo Mamzer refers to it. From it (Eshes Aviv) there is a Mamzer, for it is Chayavei Misas Beis Din.

It (Lo Yavo Mamzer) does not refer to Lo Yegaleh [Kenaf Aviv]. "Between Lo Yikach and Lo Yegaleh" refers to Eshes Av, which is written between "Lo Yikach" and "Lo Yegaleh."

Question #1: Rashi erases from the text of Seforim.

Question #2: "Between Lo Yikach and Lo Yegaleh" does not connote like he explained, that it refers to Eshes Av, which is written between them.

Question #3: Why was "Lo Yegaleh" written near Mamzerus?

Question #4: What is the source that lenient Misos Beis Din such as Eshes Ish produce Mamzerim?

Question #5: R. Yehoshua should learn other Chayavei Kerisos from R. Yonah's Hekesh [of all the Arayos to each other]!

Answer (Ri): The text of Seforim is correct. It says "the Torah should have written either Lo Yikach or Lo Yegaleh";

Also from Lo Yikach we learn Kerisus, for they are like Eshes Av, in which Kidushin does not take effect! These (Mamzerus and Kidushin Tofsin) depend on each other, like I explained above (44b);

Or, we learn [other Chayavei Kerisos] from R. Yonah's Hekesh of all the Arayos, like it says below (54b);

Since the Torah wrote both of them, this teaches that from Lo Yikach, i.e. Chayavei Skilah, until Lo Yigaleh, which is Chayavei Kerisos, a Mamzer results;

This comes to include all light Misos. He holds like Rabanan, that [Lo Yigaleh] refers to the Shomeres Yavam of his father. Lo Yigaleh (a Chiyuv Kares) is not included [in what produces a Mamzer].

If it were included, the Torah should have written only Lo Yigaleh!

Implied question: We could have said that also Shimon ha'Teimani holds like R. Yehudah, who says that the verse discusses Anusas Aviv! From Lo Yikach until Lo Yigaleh, the child is a Mamzer; Lo Yigaleh is not included.

Answer: We prefer to say that he holds like Rabanan.

Observation: According to the Ri, we must say that the Tana of the first Perek holds like R. Yehudah, who says that the verse discusses Anusas Aviv, and he holds that Mamzerim do not result from Chayavei Lavin;

From Lo Yikach until Lo Yigaleh, the child is a Mamzer; Lo Yigaleh is not included.

Explanation #1 (Rashi): Even R. Akiva, who argues with Rabanan in our Mishnah about Machazir Gerushaso, and says that the child is a Mamzer, even though it is not Chayavei Lavin of She'er, here regarding Sotah he admits.

Question #1 (R. Tam): If so, we should have brought this above (44a) regarding the Mishnah of Machazir Gerushaso!

Question #2 (R. Tam): If "all agree" refers to the opinion that R. Akiva holds that Mamzerim result even from Chayavei Lavin not of She'er [why does the Beraisa (Amud B) say that all agree that there is not a Mamzer from Yevamah l'Shuk]?

You must say that there is a Mamzer from Yevamah l'Shuk according to some Tana!

Proof #1 - Citation (14a - R. Elazar): Even though Beis Shamai and Beis Hillel argue about Tzaros, they agree that Mamzerim come only [from Arayos punishable by Kares]!

Citation (cont.): He taught this to disagree with R. Akiva, who says that Kidushin does not take effect with Chayavei Lavin [so the child is a Mamzer. Our text there discusses only Mamzer, and not Ein Kidushin Tofsin.]

Inference: According to R. Akiva, the child of a Shomeres Yavam [l'Shuk] is a Mamzer.

Proof #2: In Kidushin (75b), regarding [why R. Akiva disqualifies] the Kusim, who used to do Yibum with Arusos and exempt Nesu'os [from Chalitzah and Yibum], it says that R. Akiva teaches like he taught elsewhere, that Kidushin does not take effect with Chayavei Lavin.

Proof #3: Below (92a), regarding a woman whose husband and son went overseas, we say "this is R. Akiva's opinion, who says that Ein Kidushin Tofsin b'Chayavei Lavin, but Chachamim say that a Mamzer does not result from a Yevamah [l'Shuk];

Citation (92a) Question: Why didn't they say [that Chachamim say] that a Mamzer does not result from Chayavei Lavin?

Citation (cont.) Answer: This Tana holds that R. Akiva holds that a Mamzer results from Chayavei Lavin only if they are of She'er, but not from plain Chayavei Lavin.

Inference: According to the opinion that R. Akiva does not require Chayavei Lavin of She'er [to produce Mamzerim], there is a Mamzer from a Yevamah l'Shuk!

Reference: There we will explain, with Hash-m's help, how we know that it is like R. Akiva. Perhaps it is even like Rabanan, and it is a Mamzer mid'Rabanan!

Explanation #2 (R. Tam): Machazir Gerushaso and Sotah are Chayavei Lavin of She'er, since they are forbidden only due to marriage.

We discuss according to the Tana of our Mishnah, who forbids [says that the child is a Mamzer according to R. Akiva] only from Chayavei Lavin of She'er.

Question: If so, why did [the Beraisa] need to say "all agree about a Shomeres Yavam"? Why would I think that the child is a Mamzer more than from other Chayavei Lavin not of She'er?

Answer: According to Rav, who says that Kidushin does not take effect on a Yevamah [l'Shuk], we truly need to hear that the child is not a Mamzer.

Explanation (R. Tam): This (a Yevamah l'Shuk) is like a Nochri and slave, who does not have Kidushin with anyone;

Also with the Yavam she cannot have Kidushin. Only Bi'ah takes effect on her.

Implied question: According to the opinion that the child is a Mamzer from a Nochri or slave [who has Bi'ah with a Yisraelis, the same should apply to a Yevamah who married l'Shuk]!

Answer: There is no Mamzer from a Yevamah. Since she is "destined" to [possibly] do Chalitzah just as much as she is "destined" to [possibly] do Yibum, it is considered that Kidushin Tofsin in her.

Question: According to Shmuel, we should resolve from this Beraisa that Kidushin does not take effect on a Yevamah!

If Kidushin Tofsin in her, there would be no need to teach that the child is not a Mamzer!

Answer: Shmuel was unsure. Perhaps the Beraisa comes to teach that Kidushin Tofsin in a Yevamah! (This is why the child is not a Mamzer.)

Question: How does this teach that Kidushin Tofsin in her? Even if Kidushin does not take effect on her, the child is not a Mamzer, for Shmuel holds above (45a) that if a Nochri or slave has Bi'ah with a Yisraelis, the child is Kosher!

Answer: It properly teaches that Kidushin Tofsin in her, since it includes her with Sotah and Nidah. This implies that for all of them, the child is not a Mamzer because Kidushin Tofsin Bah.

Explanation #1 (Rashi): Abaye [did not say that there is no Mamzer from a Yavam because] he was unsure whether [the Halachah follows] Rav or Shmuel.

Rejection: Even according to Rav, the child is not a Mamzer, like I explained!

Rather, he did not do not a Shomeres Yavam, for perhaps Kidushin Tofsin Bah, like Shmuel, and obviously the child is not a Mamzer; this is no Chidush.

Question #1: Why is there a Mamzer from a Shomeres Yavam according to any Tana, since she is like a Nochri or slave? She cannot have Kidushin with him (the Yavam), nor with anyone else!

Question #2: Also, the Beraisa below (92a), which says "this is R. Akiva's opinion, who says that Kidushin does not take effect with Chayavei Lavin, but Chachamim say..." connotes that Chachamim hold that the child is not a Mamzer because Kidushin Tofsin;

According to R. Tam, even if Kidushin does not take effect, the child is not a Mamzer!

Answer (Ri): According to the opinion that R. Akiva holds that Mamzerim result also from Chayavei Lavin not of She'er, the child is a Mamzer also from a Yevamah, Nochri and slave.

Implied question: They are not like Eshes Av! (They cannot have Kidushin with anyone.)

Answer: We learn all of them from the Vov in v'Lo Yigaleh. This is written next to Lo Yavo Mamzer. We do not learn anything from Eshes Av. Rather, Mamzerus is explicitly written in all of them (i.e. the Vov includes them);

However, according to the Tana of our Mishnah, that R. Akiva holds that Mamzerim result only from Chayavei Lavin of She'er, and he does not expound the Vov in v'Lo Yigaleh, we do not derive [from it] any [other] Chayavei Lavin;

Rather, from Eshes Av we require that it is like Eshes Av, that she cannot have Kidushin with him, but she has Kidushin with others.

The Beraisa below (92a) means as follows. This is R. Akiva's opinion, who says that Kidushin does not take effect even with all Chayavei Lavin not of She'er.

I.e. from the Vov in v'Lo Yigaleh we learn all of them that the child is a Mamzer, therefore Kidushin does not take effect in all of them.

This is why we do not distinguish between the Lav of Yevamah l'Shuk and other Lavin, like I explained.

However, Chachamim say "there is no Mamzer from a Yevamah";

Since Kidushin Tofsin in Chayavei Lavin not of She'er, and there is no Mamzer from them, also there is no Mamzer from Yevamah l'Shuk, even though Kidushin does not take effect in her, since she is not like Eshes Av.

Explanation #1 (Rashi): Even after she was Mezanah, her initial Kidushin is not uprooted.

Question (Ri): Also a Nidah, her Kidushin is not uprooted, and even so we need a verse to teach that Kidushin Tofsin Bah!

Explanation #2 (Ri): The text in most Seforim says "also regarding Sotah, Havayah is written, and Kidushin Tofsin Bah!

I.e. if he divorced and remarried her. The Havayah written about her is "Lihyos Lo l'Ishah", which we established above (11b) to include a Sotah.

Support #1: Below (85b) connotes that Kidushin Tofsin in a Vadai Sotah. They argue only about whether or not she has a Kesuvah.

Citation (85b): They argue about a Vadai Sotah. The one who says [that she has a Kesuvah] when the Torah forbids them, also this is a Torah Isur, so she has a Kesuvah.

Explanation: You must say that this refers to one who remarried a Sotah after divorcing her. If he did not divorce her, since she was Mezanah, she forfeited her Kesuvah.

Support #2: Also in Kidushin (78a) it connotes that "Lihyos Lo l'Ishah" is an expression of Havayah;

It says "both of them agree about Machazir Gerushaso, that if he had Bi'ah without Kidushin, he is not lashed. The Torah forbade through Havayah."

Question: In Kidushin (68a), we ask how R. Akiva establishes "Ki Sihyena" (that a man will have a Senu'ah (forbidden) wife, since he holds that Kidushin does not take effect with Chayavei Lavin). He should establish it to discuss one who remarried a Sotah!

Suggestion: "Ki Sihyena" is extra [to teach a Chidush], and we already know about one who remarried a Sotah from "Lihyos Lo l'Ishah".

Question: If so, how can we establish it to discuss a widow to a Kohen Gadol, according to R. Simai? [We already know this, for] it says "Lo Yechalel" - "he makes Chilulim (Chalalim), but not Mamzerim!

Answer: We don't establish it to discuss one who remarried a Sotah because "Senu'ah" connotes that she was hated from the beginning of the marriage.

Question: Why don't we establish it to discuss a Sotah who married the Bo'el?

Answer #1: It does not say 'Ki Sihyena l'Bo'el', like it says there 'does it say 'Ki Sihyena l'Kohen'?!'

Answer #2: Regarding the Bo'el it does not say Havayah, so Ein Kidushin Tofsin Bah.

R. Chananel's opinion: Granted, there is no Mamzer mid'Oraisa from a Sotah, but mid'Rabanan there is a Mamzer;

This is like a woman whose husband went overseas, and they told her that he died, and she remarried, and afterwards her husband returned. The child is a Mamzer, and she must leave both husbands.

Objection #1: This is no proof. There they fined her, in order that she will be careful [to ensure that her husband truly died before remarrying]. Here, there is no need to fine her lest she be Mezanah while married.

Objection #2: Below (85b), we say regarding [remarrying] a Sotah [after he divorced her] that according to the opinion that [a forbidden wife has no Kesuvah] in any case when she entices him to marry her, here she entices him;

If the child is a Mamzer, even mid'Rabanan, she would not entice him, like it says there about a Chalutzah.

Explanation #1: Rashi connotes that according to Rav, no Lav forbids a Yevamah [l'Shuk];

He explained that according to Rav, who says below (92b) "what is the source that Ein Kidushin Tofsin in a Yevamah? It says "Lo Sihyeh..." - she will not have Havayah with a Zar, and the child is a Mamzer;

According to Shmuel, who is unsure whether the verse comes to teach like Rav says, or perhaps to forbid her with a Lav, and Kidushin Tofsin Bah, since the Lav was taught in an expression of Havayah.

Rejection: It says in Kidushin (68a) "just like Yevamah has a Lav, and Ein Kidushin Tofsin Bah". This shows that there is a Lav even according to the opinion that Ein Kidushin Tofsin Bah!

Everywhere, Yevamah l'Shuk is considered Chayavei Lavin.

Those who asked (above, 15b) R. Yehoshua about Bnei Tzaros [Ervah] of Beis Hillel ac [who remarried without Chalitzah] according to Beis Shamai (who hold that this is Yevamah l'Shuk), for they wanted to learn Yevamah l'Shuk from a Kal va'Chomer from a widow [to a Kohen Gadol]. This shows that there is a Lav!

Answer (R. Tam): All agree that there is a Lav. The Gemara means that Shmuel is unsure if the verse teaches a Lav, and "Sihyeh" is just the way the verse speaks (it does not teach about Kidushin);

Or, perhaps it also teaches that one is lashed for Kidushin, or that Ein Kidushin Tofsin.

Explanation (R. Chananel): He wanted to answer him that regarding [those with] Moshe it says "va'Yir'u Es Elokei Yisrael." (I.e. Lo Yir'ani ha'Adam va'Chai means that people cannot see [the honor of] Hash-m clearly. Even so, Yeshayah could say "va'Er'eh Es Hash-m", like the verse says about those with Moshe - Aruch l'Ner.)