Answer #2: Just like one brings a Korban for Sheker, also for Shav;

The Beraisa is R. Akiva, who obligates a Korban for oaths of the past like for the future.

Question (Beraisa): A Shav oath is one that everyone knows to be false. Sheker is swearing to change (from the truth, i.e. something of the past).

Answer: The Beraisa means, Sheker is swearing and changing (from what he swore to do, i.e. in the future).

(Ravin citing R. Avahu citing R. Yochanan): If one falsely swore 'I ate' or 'I did not eat', this is Sheker. V'Lo Sishav'u bi'Shmi la'Shaker" forbids it;

If he swore 'I will eat' or 'I will not eat', he is commanded "Lo Yachel Devaro."

A Shav oath is one that everyone knows to be false.

(Rav Papa): R. Yochanan did not explicitly say the above teaching. Rather, R. Avahu inferred it from the following.

(Rav Idi bar Avin citing R. Yochanan): One is lashed for a Lav that is done through an action;

The only Lavim without an action for which one is lashed are swearing (falsely), Temurah and cursing a Yisrael with Hash-m's name.

Question: What is the source of lashes for swearing?

Answer (R. Yochanan): "Lo Sisa... la'Shav Ki Lo Yenakeh" - the Heavenly court does not cleanse, but Beis Din lashes and cleanses.

Question (Rav Papa): Perhaps it is not cleansed at all!

Answer (Abaye): Had it said only "Lo Yenakeh", that would be correct;

Rather, it says "Lo Yenakeh Hash-m", but Beis Din cleanses.

Question: This teaches about lashes only for a Shav oath. What is the source for Sheker?

Answer (R. Yochanan): It says twice "la'Shav";

We use the extra one to teach about Sheker.

Question (R. Avahu): What kind of Sheker do we learn to?

Suggestion: If he swore 'I will not eat' and he ate, he transgressed through an action! (We already know that he is lashed.)

Answer #1: Rather, he swore 'I will eat', and he did not eat.

Objection: He is not lashed for this!

(R. Yochanan and Reish Lakish): If one swore 'I will eat this loaf today' and he did not, he is not lashed.

(R. Yochanan): He is not lashed because he transgressed without an action. One is not lashed for such a Lav;

(Reish Lakish): He is not lashed because he did not receive definite warning (right before transgressing, at the end of the day. No one knows precisely when the day ends.)

Answer #2 (R. Avahu): Rather, he swore 'I ate' or 'I did not eat.'

Question: Here also, he transgressed without an action. Why is he lashed?

Answer (Rava): The Torah teaches that one is lashed for Sheker that resembles Shav, i.e. in the past.

Question (against R. Avahu - R. Yirmeyah - Mishnah): If Reuven said 'I swear that I will not eat this loaf, I swear that I will not eat it, I swear that I will not eat it' and ate it, he is liable only for one oath;

This is the Shevu'ah of Bituy for which one is lashed if he was Mezid, and brings an Oleh v'Yored if he was Shogeg.

Suggestion: 'This' excludes 'I ate' or 'I did not eat.' He is not lashed for them!

Answer #1: No, it excludes 'I ate' or 'I did not eat', to teach that he does not bring a Korban for them;

The Mishnah is R. Yishmael, who says that a Korban is brought only for oaths about the future;

He is lashed for 'I ate' or 'I did not eat.'

Question (Seifa): This is the Shevu'as Shav for which there are lashes, but not a Korban;

Suggestion: This excludes 'I ate' or 'I did not eat.' He is not lashed for them!

Answer: No, it excludes 'I ate' or 'I did not eat', to teach that he brings a Korban for them;

This is like R. Akiva, who obligates a Korban for the past like for the future.

Objection: Is the Reisha R. Yishmael, and the Seifa is R. Akiva?!

Answer #2: The entire Mishnah is R. Akiva;

The Reisha does not exclude 'I ate' or 'I did not eat' from a Korban. Rather, it excludes 'I will eat' from lashes (if he does not eat, since he transgresses through inaction), but he brings a Korban (if he was Shogeg).

Version #1 (Rashi) Question: Why didn't he say that the Reisha excludes also 'I ate' and 'I did not eat' from lashes?

Version #2 (Tosfos) Question: Why didn't he answer that the entire Mishnah is R. Yishmael? The Reisha excludes 'I ate' and 'I did not eat' from lashes, and the Seifa excludes them from a Korban. (end of Version #2)

Answer: The Reisha teaches about an oath of the future. Presumably, it excludes an oath of the future.

(Mishnah - R. Akiva): If one swore 'I will not eat' and he ate Mashehu, he is liable...

Question: How does R. Akiva hold in general?

Possibility #1: He holds like R. Shimon, that one is lashed for eating Mashehu of any prohibition;

(Beraisa - R. Shimon): One is lashed for eating Mashehu of any prohibition. A k'Zayis (the volume of an olive) pertains only to bringing a Korban.

Really, the argument of R. Akiva and Chachamim could have been taught elsewhere. It was taught about Shevu'os to teach that Chachamim do not say that just like he is liable for Mashehu if he specifies (in the oath that he will not eat Mashehu), he is liable for Mashehu (even without specifying),

Possibility #2: Normally, R. Akiva holds like Chachamim;

Only regarding Shevu'os he obligates for Mashehu, just like he is liable for Mashehu if he specifies.

Answer #1 (Mishnah - Chachamim): We never find that someone is liable for eating Mashehu!

If R. Akiva normally holds like R. Shimon, he should answer 'I hold that one is always liable for eating Mashehu'!

Rejection: R. Akiva answered Chachamim according to their opinion;

I normally hold like R. Shimon. You should admit to me about Shevu'os, for just like he is liable for Mashehu if he specifies, he is liable for Mashehu even without specifying.

Chachamim did not agree.

Answer #2 (Mishnah - R. Akiva): If a Nazir ate bread that was soaked in wine and there is a k'Zayis of wine and bread together, he is liable.

If he normally held like R. Shimon, a Nazir would be liable for Mashehu of wine, so there would be no need to join to a k'Zayis! (This proof is accepted. We bring another proof, anyway.)

Answer #3 (Mishnah): If one swore 'I will not eat', and he ate Neveilos, Treifos, rodents or insects, he is liable (for the oath);

R. Shimon exempts.

Question: Why do Chachamim obligate him? The oath (that Yisrael accepted on Sinai) already obligates him not to eat them (so his oath does not takes effect)!

Answer #1 (Rav, Shmuel and R. Yochanan): Since his oath takes effect on permitted food, it takes effect also on forbidden food.

Answer #2 (Reish Lakish): The Torah forbids him only from eating a k'Zayis of these things. His oath forbids him from eating Mashehu;

We find this according to Chachamim if he specified (Mashehu), or according to R. Akiva even without specifying.

Culmination of answer: If R. Akiva held like R. Shimon, the Torah forbids him from eating Mashehu!

We conclude (from Reish Lakish) that normally, R. Akiva does not hold like R. Shimon.

(Mishnah - Chachamim): We never find that someone is liable for eating Mashehu!

Question: One is liable for eating an ant of any size!

Answer: That is because it is a full creation.

Question: One is liable for eating Hekdesh, even less than a k'Zayis!

Answer: There is a minimum quantity (albeit of value) for liability, i.e. a Perutah.

Question: If one specified in his oath, he is liable for Mashehu!

Answer: There, he showed that Mashehu is important to him, so he is liable for it, just like for a creation.

Question: Why don't we say that he is liable for Mashehu of dirt (i.e. a k'Zayis is the quantity only for things normally eaten)?

Suggestion: Since Chachamim say that he is never liable for Mashehu, they must hold that one is liable for dirt only for a k'Zayis. This settles Rava's question!

Question (Rava): If one said 'I swear that I will not eat', and he ate dirt, how much must he eat to be liable?

Answer (and rejection of suggestion): Chachamim meant that we never find that one is liable for eating Mashehu of something that is normally eaten.

Question: One is liable for eating Mashehu of Konamos (something forbidden through a Neder)!

Answer: Also Konamos is like specifying (Mashehu, since he does not mention eating).