Answer (Ameimar): Normally, Rebbi expounds Klal u'Frat. Redemption of a firstborn is different, like Tana d'Vei R. Yishmael taught.

(Beraisa - Tana d'Vei R. Yishmael): It says (regarding Simanim of Kosher fish) twice "ba'Mayim" (and afterwards, Pratim). Therefore, we do not expound according to Klal u'Frat, rather, according to Ribuy and Mi'ut.

Question: Why do Chachamim argue with Rebbi about redemption of a firstborn son? (Since the Klalim are adjacent, they should agree that we expound through Ribuy and Mi'ut!

Answer (Ravina): Chachamim expound like Chachamim of Eretz Yisrael;

(Chachamim of Eretz Yisrael): Whenever there are two adjacent Klalim, we put the Pratim in the middle and expound through Klal u'Frat.

Question: Since Rebbi normally expounds according to Klal u'Frat, surely he holds like R. Yishmael regarding oaths!

Answer: Indeed, Rebbi taught R. Akiva's opinion regarding oaths, even though he disagrees.

(Beraisa - R. Akiva): "V'Ne'elam... v'Ne'elam" teaches that one brings a Korban only if he knew at the beginning and at the end, and forgot in between (when he transgressed);

Rebbi says, "v'Ne'elam" connotes that he knew. "V'Hu Yada" also teaches this!

The extra "v'Ne'elam" obligates him, whether he forgot the Tum'ah or the Mikdash (or Kodshim). This is like R. Yishmael.

Question: Rebbi says that "v'Ne'elam" connotes that he knew. How is this implied?

Answer #1 (Rava): It is because it does not say 'it was hidden from him' (which would imply that he never knew).

Objection #1 (Abaye): It says about a Sotah "v'Ne'lam me'Einei Ishah." Will you say that he knew and forgot?!

"V'Nikah ha'Ish me'Avon and she will bear her sin" - the water tests her only if her husband acted properly. (Tosfos - even if he did not have Bi'ah with her afterwards, forgetting that she became forbidden to him is a gross negligence.)

Objection #2 (Abaye): Regarding Torah, it says "v'Ne'elmah me'Einei Kol Chai." Will you say that it was once known?!

"Lo Yada Enosh Erkah" (no person knows its worth)!

Answer #2 (Abaye): Rebbi considers having learned the laws of Tum'ah (Rashi - and having felt the rodent when it touched him, even though he did not reflect and realize that he is Tamei) as having once known. (Had he thought about the Tum'ah, he would have known to avoid transgressing.)

Question (Rav Papa - Mishnah): If he never knew of the Tum'ah (and entered the Mikdash or ate Kodshim), and later was told that he was Tamei...

Surely, any adult once learned the laws of Tum'ah!

Answer (Abaye): The case is, when he was a child, he was captured by Nochrim (and never learned the laws of Tum'ah).

(Mishnah): There are two primary forms of Yetzi'ah on Shabbos. There are four in all.

(Mishnah (in tractate Shabbos)): There are two primary forms of Yetzi'ah and two secondary forms inside (Rashi - bringing something into a Reshus ha'Yachid; Tosfos - regarding a person standing in a Reshus ha'Yachid);

There are also two primary and two secondary Yetzi'os outside.

Question: Why does our Tana mention only four of the eight?

Answer #1: There, the focus of the tractate is the laws of Shabbos, so the Tana mentions also the derivative Melachos;

Our tractate does not focus on the laws of Shabbos (it is merely brought in passing), so the Tana mentions only the Av Melachos.

Question: The Avos are Yetzi'os. There are only two of them (yet our Mishnah mentions four)!

Suggestion: Perhaps the Mishnah mentions Avos that one is liable for, and also those for which one is exempt!

Rejection: Presumably, the Yetzi'os are similar to appearances of Tzara'as, i.e. one is liable for all of them.

Answer #2 (Rav Papa): There, the focus of the tractate is Shabbos, so the Tana mentions Yetzi'os for which one is liable, and for which one is exempt;

Our tractate does not focus on the laws of Shabbos, so the Tana mentions only Yetzi'os for which one is liable.

Question: There are only two Yetzi'os for which one is liable for (yet our Mishnah mentions four)!

Answer: There are also two Hachnasos (bringing something into a Reshus ha'Yachid).

Question: The Tana says there are a total of four Yetzi'os!

Answer #1 (Rav Ashi): Hachnasos are also called Yetzi'os.

Question: What is the source to say this?

Answer (Mishnah): One who is Motzi from one domain to another domain is liable.

This includes taking from a Reshus ha'Rabim to a Reshus ha'Yachid, and the Tana calls it Hotza'ah!

Question: Perhaps it only refers to taking from a Reshus ha'Yachid to a Reshus ha'Rabim!

Answer: If so, it should have said 'one who is Motzi from a Reshus ha'Yachid to a Reshus ha'Rabim';

Rather, it says 'from one domain to another domain' to teach both directions;

Why is that?

Any uprooting of an object from its place is called Hotza'ah.

Support (Ravina - Mishnah): There are two primary forms of Yetzi'ah and two secondary forms inside, and two primary and two secondary Yetzi'os outside;

The Tana then details the Yetzi'os, and some are Hachnasos!

Version #1 - Rashi - Answer #2 (Rava): The Tana (there) says that there are two domains of Shabbos, which lead to four Isurim inside and four outside.:

Version #2 - Tosfos - Answer #2 (Rava): The Tana (there) says that (transferring between) domains of Shabbos entails two Isurim for which one is liable (and four in all) inside, and two Isurim of liability and four in all outside.

(Mishnah): There are two primary appearances of Tzara'as. There are four in all.

(Mishnah (in tractate Nega'im)): There are two primary appearances of Tzara'as. There are four in all. Baheres is as bright as snow. Its secondary appearance is k'Sid (like plaster of) the Heichal. Se'es is like white wool. Its secondary appearance is k'Karom (like the membrane of) an egg.

(R. Chanina): This latter Mishnah is not like R. Akiva.

Version #1 (Rashi, Tosfos): R. Akiva says that the different appearances are one above (whiter than) the other. (Different appearances join together to complete the area of plagued skin only if there is not another of the four appearances in between.)

If the Mishnah were R. Akiva, k'Sid would not join with any appearance!

It cannot join with Baheres, because Baheres is not directly whiter than it (Se'es is in between);

It cannot join with Se'es, because our Mishnah says that it is not a secondary appearance of Se'es! (Tosfos - it teaches precisely this, that it does not join with Se'es; R. Akiva himself holds that it joins to Se'es, even though it is secondary to Baheres. Rashi - R. Akiva holds that k'Sid is secondary to Se'es).

(Other versions: Ba'al ha'Ma'or - our Mishnah holds that there are only three different shades of white. Se'es is also k'Sid, but plagues of Se'es and k'Sid have different textures. Ramban - R. Akiva holds that all the appearances are the same shade of white. They vary only in intensity. Gra - R. Chanina holds that R. Akiva says that Se'es is whiter than k'Sid, unlike our Mishnah which puts k'Sid second to Baheres. We explain below only according to Rashi and Tosfos.)

Question: If so, also k'Karom would not join with any appearance!

It cannot join with Se'es, because Se'es is not directly whiter than it (k'Sid is in between);

It cannot join with k'Sid, because it is from a different primary appearance than k'Sid!

Rejection: k'Karom is not a question;

"Vela'Se'es vela'Sapachas" teaches that the secondary appearance of Se'es joins with Se'es, even though Se'es is not directly whiter than it.

The question from k'Sid remains (if the Mishnah is R. Akiva, and nothing joins with it);

Conclusion: The Mishnah is not R. Akiva.