Question: What does R. Eliezer learn from "Bah"

Answer: This excludes Mis'asek (one who did an action he did not intend for).

Answer #2 (to Question 3:b, 18b - R. Yochanan and Rav Sheshes): R. Eliezer and R. Akiva do not argue about the law, only about how we derive it.

Since Rav Sheshes held that they do not argue about the law, he was not careful and sometimes switched the opinions of R. Eliezer and R. Akiva.

Question (Rava): If one forgot that he was Tamei and the place of the Mikdash (or that this meat is Kodesh), what is the law (according to R. Eliezer and R. Akiva, that one is liable for forgetting the Tum'ah, and not for forgetting the Mikdash)?

Answer #1 (Rav Nachman): Since he forgot the Tum'ah, he is liable.

Question: Why not say the contrary, that since he forgot the Mikdash, he is exempt!

Answer #2 (Rav Ashi): It depends. If he would have refrained had he remembered the Tum'ah, this is like forgetting the Tum'ah, so he is liable;

If he would have refrained had he remembered the Mikdash, this is like forgetting the Mikdash, so he is exempt.

Objection (Ravina): Had he remembered only one of them, he would not refrain!

Answer #3 (Ravina): Rather, in either case he is exempt.

(Beraisa): If there are two paths, and somewhere along one of them there is a Mes under the ground spanning the entire width of the path, anyone who walks on that path will become Tamei.

If a man walked on one path, and later on the other path, and then entered the Mikdash, he is liable (since he is Vadai (surely) Tamei);

If he man walked on one path, entered the Mikdash, was sprinkled (with Mei Chatas, to become Vadai Tahor), walked on the other path and entered the Mikdash, he is liable (since one of the times he entered the Mikdash he was Tamei);

R. Shimon exempts;

R. Shimon ben Yehudah cites R. Shimon to say that he is exempt in every case.

Question: Does R. Shimon ben Yehudah exempt even in the first case? No matter which path is Tamei, he was Tamei when he entered the Mikdash!

Answer (Rava): The case is, when he walked on the second path he forgot that he had walked on the first path, so he never knew for sure that he was Tamei.

The first Tana holds (according to R. Shimon) that partial knowledge is like full knowledge (that he was Tamei);

R. Shimon ben Yehudah holds (according to R. Shimon) that partial knowledge is not like full knowledge.

(Beraisa): If he man walked on one path, entered the Mikdash, was sprinkled, walked on the other path and entered the Mikdash, he is liable. R. Shimon exempts.

Question: Why does the first Tana obligate him? Each time he entered the Mikdash, he only knew (initially and forgot) that he was Safek Tamei!

Answer #1 (R. Yochanan): Here, knowledge of a Safek is considered like (full) Yedi'ah;

Answer #2 (Reish Lakish): The Beraisa is R. Yishmael, who does not require initial knowledge.

Question: R. Yochanan and Reish Lakish both contradict what they said elsewhere!

(Beraisa - Rebbi): If b'Shogeg, one ate Safek Chelev, then found out (that he ate Safek Chelev), and again ate and found out, just like one brings a Chatas for each time he (b'Shogeg) ate (Vadai) Chelev (after realizing his previous mistake), so he brings an Asham Taluy for each time he (b'Shogeg) ate Safek Chelev (after realizing his previous mistake);

R. Shimon ben Yehudah and R. Elazar b'Rebbi Shimon say, he brings only one Asham Taluy;

"Al Shigegaso Asher Shagag" teaches that one Asham Taluy atones for many mistakes.

(Reish Lakish): Rebbi holds that Yedi'ah of Safek transgression separates, and obligates a separate Chatas (if he later learns that he truly transgressed) for his transgressions before the Yedi'ah and after, just like it separates regarding Asham Taluy (it obligates him to bring another Asham for Safek transgressions after the Yedi'ah);

(R. Yochanan): Just like Vadai Yedi'ah separates for Chatas, Safek Yedi'ah separates for Asham.

Answer (for R. Yochanan): We only inferred that Yedi'ah is needed for Tum'ah from "v'Nelam", therefore Safek Yedi'ah is considered Yedi'ah;

Regarding Chatas, it explicitly says "Oh Hoda Elav." Full Yedi'ah is needed.

Clarification of the question against Reish Lakish: If he holds (according to Rebbi) that Safek Yedi'ah is considered Yedi'ah (even for Chatas), why did he establish the Beraisa like R. Yishmael (who does not require initial Yedi'ah)? It could be (like Chachamim, who require initial Yedi'ah) according to Rebbi!

Answer: Reish Lakish wanted to teach that R. Yishmael does not require initial Yedi'ah.

Objection: This is obvious! Since he expounds "v'Nelam" to obligate for forgetting the Mikdash, he has no source to require initial Yedi'ah!

Answer: One might have thought that he has no source from the verses, but he has a tradition from Moshe from Sinai to require it;

Reish Lakish teaches that this is not so.

(Mishnah): There are two primary kinds of Shevu'os (of Bituy). There are four in all;

The two primary kinds are 'I swear that I will eat' and 'I swear that I will not eat';

The other two are 'I swear that I ate' and 'I swear that I did not eat.'

R. Akiva says, if one swore 'I will not eat' and he ate Mashehu (any amount), he is liable;

Chachamim: We never find that someone is liable for eating Mashehu!

R. Akiva: We never find that one brings a Korban for speaking! (The Korban is for transgressing his words. His intention was not to eat at all. If he eats Mashehu he transgressed!)

(Gemara) Inference: Our Mishnah teaches that 'she'Ochel' means 'I will eat.'

Contradiction (Beraisa (Tosfos - an abridged form of a Mishnah)): If one said 'I swear that I will not eat your food' or 'I swear she'Ochel (your food)' or 'I do not swear that I will not eat', he is forbidden to eat.