(Rav Nachman): If Reuven saw Shimon slaughter from the beginning until the end, he may eat from the Shechitah. If not, he may not.

Question: What is the case?

If Reuven knows that Shimon knows the laws of Shechitah, why must he see the entire Shechitah?

If he knows that Shimon does not know the laws, obviously he must see the entire Shechitah!

Suggestion: Reuven is unsure whether Shimon knows the laws.

Objection: We should say that most people who slaughter know the laws! (It should be permitted, even if Reuven did not see the Shechitah.)

(Beraisa): If a slaughtered chicken was found in the market, or if Levi told a Shali'ach to slaughter, and Levi (Rashi, according to Shitah Mekubetzes; Tosfos - the Shali'ach) found the animal slaughtered, we assume that it was slaughtered properly.

We assume that the Shochet (the one who slaughters) knows the laws, since those who do not know, do not slaughter!

Answer: Really, Reuven knows that Shimon does not know the laws. The case is, he saw Shimon cut one Siman;

One might have thought that since he cut one properly, we may assume that he cut the second properly.

Rav Nachman teaches that this is not so. He must see both Simanim cut. Perhaps he happened to cut the first Siman properly, but he paused or Daras while cutting the second Siman.

Question (Rav Dimi bar Yosef): If Reuven asked a messenger to slaughter for him and later found the animal slaughtered, what is the law?

Answer (Rav Nachman): He may assume that it was slaughtered properly.

Question (Rav Dimi bar Yosef): If Reuven asked a messenger to take Ma'aser for him and later found the Ma'aseros separated, what is the law?

Answer (Rav Nachman): He may not assume that the Ma'aseros were separated properly.

Objection (Rav Dimi bar Yosef): This is inconsistent!

If there is a Chazakah that a Shali'ach fulfills his mission, we should assume also that Ma'aseros were separated properly!

If there is no such Chazakah, why may we assume that the animal was slaughtered properly?

Answer (Rav Nachman): Really, there is no such Chazakah;

Regarding Shechitah, even if someone (Ploni) overheard Reuven command the Shali'ach (and Ploni slaughtered the animal), most people who slaughter know the laws, so we assume that Ploni is from the majority;

Regarding Ma'aser, if Ploni overheard and took Ma'aser for Reuven, it is invalid, for Ma'aser cannot be taken without the owner's request.

Suggestion: Tana'im argue about whether most who slaughter know the laws.

(Beraisa - R. Yehudah): If Reuven lost his goats and chickens, and found them slaughtered, one may not eat them;

R. Chanina, son of R. Yosi ha'Gelili permits them;

Rebbi: R. Yehudah's opinion is Nir'eh (correct) when he found them in a trash heap. R. Chanina's opinion is Nir'eh when he finds them in the house.

Suggestion: R. Chanina holds that most who slaughter know the laws, and R. Yehudah disagrees.

Rejection (Rav Nachman bar Yitzchak): No, all agree that most who slaughter know the laws;

If the slaughtered animals are found in the house, all permit them. If they are found in a trash heap in the market, all forbid them;

They argue about animals found in a trash heap in the house.

R. Yehudah holds that one often casts a Neveilah in a trash heap in his house. R. Chanina disagrees.

(Beraisa - Rebbi): R. Yehudah's opinion is Nir'eh when he found them in a trash heap...

Question: To which trash heap does he refer?

He cannot mean a trash heap in the market. Rav Nachman bar Yitzchak said all agree in that case!

Answer: Rather, he refers to a trash heap in the house.

Question (Seifa - Rebbi): R. Chanina's opinion is Nir'eh when he finds them in the house.

Question: In what part of the house did he find them?

Suggestion: He found them in a proper part of the house.

Rejection: Rav Nachman bar Yitzchak said that all agree in such a case!

Answer: Rather, he found them in a trash heap in the house.

Contradiction: In the beginning of the Beraisa, Rebbi agreed with R. Yehudah in this case. In the end of the Beraisa, he sides with R. Chanina!

Answer: Rebbi meant that R. Yehudah's opinion is Nir'eh (appears correct) to R. Chanina (i.e. R. Chanina agrees with him) regarding a trash heap in the market (they are forbidden);

They only argue about a trash heap in the house, and in this case, R. Chanina's opinion is Nir'eh (to me, Rebbi).

(Mishnah): Except for a Cheresh, lunatic or minor, lest they (will) slaughter improperly.

It does not say, lest they slaughtered improperly, rather lest they (will) slaughter improperly.

(Rava): This teaches that l'Chatchilah, one may not let them slaughter Chulin.

(Mishnah): If any of them slaughtered while others looked on, the Shechitah is Kosher.

Question: Who is the Tana of our Mishnah, who does not require intent for Shechitah of Chulin?

Answer (Rava): It is R. Noson;

(Beraisa - R. Noson): If a man threw a knife in order to so that it will stick into a wall, and as it went it slaughtered normally, the Shechitah is valid;

Chachamim say, it is invalid.

(Oshaya Ze'ira of Chavriya): The Halachah follows R. Noson.

Question: Shechitah requires drawing the knife back and forth (unless it is a long knife)!

Answer: Indeed, the knife bounced off the wall and cut in the reverse direction as well.

Version #1 (R. Chiya bar Aba citing R. Yochanan) Question: Does intent of a minor take effect?

R. Ami: He should ask whether a minor's actions take effect!

Surely, he knew the Mishnah that teaches that a minor's actions take effect. The same Mishnah teaches that his intent does not take effect!

(Mishnah): If a child hollowed out an acorn, pomegranate or nut to measure earth, or to use in a balance scale, this makes them Kelim to be Mekabel Tum'ah, because a minor's actions take effect, but his intent does not.