Question: What is the problem, bearing in mind that, even if we were to say that here, it would not be significant, seeing as Moshe was taught on Har Sinai 'Don't leave over a majority', there would not be a majority here, and they would therefore both be Tahor?

Answer: The issue here is a question of importance, because, since Mechtzah is considered a majority, it is permitted earlier, since there is a Shi'ur of a Hechsher Shechitah - and here too, half has the importance of a majority.

Question #1: In the first Perek of Eruvin (16b) we rule like Rav Papa, who holds Parutz ke'Omeid is permitted'?

Refuted Answer: We might have drawn a distinction between other Isurim (the Sugya in Eruvin) and things that contain life (our Sugya) ...

Refutation: ... had the Gemara not cited earlier the example of 'Tanur' in our Sugya.

Question #2: Another Kashya is that, in the Sugya in Eruvin, it does not cite the case mentioned in our Sugya, nor does our Sugya cite the cases mentioned there?

Answer: Perhaps we can answer that here it is talking about Isur and Tum'ah, whereas there it is talking about Mechitzos, two issues which are simply not comparable.

Question (Part 1): Why, in the first Perek of Sanhedrin (Daf 16.) in connection with the Pasuk "Vehotzeisa es ha'Ish Hahu ... " do we Darshen 'Ish ve'Ishah Atah Motzi li'She'arecha - but not the whole tribe' ...

Question (Part 2): ... whereas here we only preclude the majority of Yisrael?

Answer #1: That is because we find there that the Torah draws a distinction between an individual and many with regard to Ir ha'Nidachas. Therefore it is logical to distinguish between an individual and a tribe, to say that a tribe is not called 'Ish'.

Answer #2: Alternatively, the Torah writes"Ish ve'Ishah" a number of times there (from one of which we will preclude the majority of Yisrael, and from a second one, a tribe).

Implied Question: Then why does the Tana then say 'Chatzi Echad be'Of ve'Echad va'Chetzi bi'Beheimah, Shechitasah Pesulah'?

Answer: That is the Seifa, which is speaking about Kodshim.

Clarification: 'Meirak' is an expression of 'completing' ...

Source: ... like we find in the Midrash that 'Someone who begins to perform a Mitzvah, we say to him 'M'rok' (Complete it)!

Alternative Question: The Gemara could equally well have asked 'If so, it will be a Shechitah performed by two people?', seeing as if he did not complete the Shechitah it is Pasul, and two people are not permitted to Shecht a Korban, even one after the other, as is evident later in the Sugya.

Question (Part 1): What is the problem with 'Avodah ba'Acher', seeing as there is an opinion in Perek Taraf be'Kalpi (Yoma 42a) which renders Kasher even the Shechitah of the Kohen Gadol's bull by a Zar? ...

Question (Part 2): ... and even the opinion that declares it Pasul, that is only the Kohen Gadol's bull, which is a Yom-Kipur obligation, regarding which the Torah writes "Aharon" and "Chukah"; but not the Tamid, which does not belong to Yom Kipur, and to which "Aharon: and "Chukah" do not relate?

Answer: It is nevertheless Pasul mi'de'Rabbanan.

Implied Question: Despite the fact that even by Chulin, one needs to sever both Simanim Lechatchilah ...

Answer: ... nevertheless, since concluding the Shechitah (on Yom Kipur) is problematic, the Kohen Gadol should not need to complete the Shechitah through somebody else.

Implied Question: Even though Rava agrees with this ruling, in the second Perek of Zevachim (Daf 30a), he nevertheless does not include it in his list of three things where he rules like Resh Lakish against Rebbi Yochanan, at the beginning of 'ha'Choletz' (Yevamos, 36a) ...

Answer (Part 2): ... because this ruling Resh Lakish cites (not in his own name, but) in the name of Levi.

Explanation #1: Rashi establishes it by a bird of Kodshim.

Question #1: What is the reason of the opinion that declares him Patur, seeing as one is not Chayav for performing Melikah outside the Azarah, only for Shechitah, in which case it cannot be said that he did an act of Hechsher Shechitah outside?

Question #2: And why does Rav Yosef say 'Because he did an act of Chatas ha'Of? He ought rather to have said 'Because the Hechsher of Shechitas ha'Of is with one Siman'?

Question #3: Moreover, Rav Yosef says that 'Echad ba'Chutz and Echad bi'Fenim is also Pasul', implying that if both would be inside, it would be Kasher. And if the Gemara is talking about a bird, its Hechsher is specially by means of Melikah, in which case he ought to have said 'Chayav', and not 'Pasul'?

Explanation #2 (Part 1): It therefore seems that the Gemara is talking about an animal, and he is Patur according to the opinion that holds 'Einah li'Shechitah Ela be'Sof''.

Explanation #2 (Part 2): ... and Rav Yosef holds that he is Chayav unanimously, seeing as he performed an act of a Chatas ha'Of outside.

Clarification: And 'Pesulah' that Rav Yosef mentions is 'La'av Davka', since he is even Chayav unanimously (as we just explained) ...

Proof (Part 1): ... because if he was not, why does he not establish the Machlokes by one Si'man outside and one Si'man inside, and they are arguing over whether he is Chayav or not ...

Proof (Part 2): ... why does he need to establish it where he Shechted a minority of the Simanim outside and completed the Shechitah inside?

Question (Part 1): At the end of the Perek (Daf 40b) where the Beraisa declares someone who Shechts a Chatas on Shabbos outside to Avodas-Kochavim Chayav three Chata'os, and which we establish there with regard to a Chatas ha'Of a half of whose wind-pipe was cut, and he added a Kolshehu, where all three Isurim come into effect simultaneously.

Clarification: The reason that the Tana mentions specifically 'Chatas' and not 'Zevach' (another Korban), is because, by any other Korban, once one Shechts one Si'man to Avodah-Zarah, one invalidates it, in which case, one would no longer be Chayav for Shechutei Chutz.

Question (Part 2): ... but now, that even by an animal one is Chayav for Shechting one Si'man because of Shechutei Chutz (as Tosfos just explained), why does the Tana not mention 'Zevach' in the same case where half the wind-pipe is already cut? ...

Refuted Answer: ... and even though on one Si'man he will not be Chayav for Shabbos, seeing as one Si'man does not achieve anything ...

Refutation: ... so what if he won't? In any event, as soon as he Shechts the second Si'man he will be Chayav because of Shabbos as well?

Answer (Part 1): The reason that he is Chayav for one Si'man in our case, is because he completes the second Si'man inside ...

Answer (Part 2): ... there on the other hand, where he Shechts to Avodas-Kochavim, since the bird became forbidden with the first Si'man, Shechting the second Si'man is akin to cutting in the dust ...

Precedent: And it can be compared to a P'sul that occurred in the Shechitah, about which the Gemara will shortly say that it is revealed that retroactively, with regard to Parah, the Shechitah was no Shechitah at all.

Conclusion (Part 1): That explains why the Gemara establishes it by a bird and not an animal.

Conclusion (Part 2): Rashi later concurs with this explanation.

Explanation #1: Rashi explains that the P'sul in question is that it became a Neveilah.

Explanation #2: But Rabeinu Tam explains that it became Pasul through another Melachah being performed with it, similar to Haza'ah ...

Proof: ... because if one will say that by Shechitah too, there will be a difference between before it became Pasul and afterwards (as implied by Rashi), then the Gemara ought to draw a distinction by Shechitah itself, so why does it mention Haza'ah? ...

Refuted Question: ... and even though we are speaking about a P'sul Melachah, the Gemara nevertheless will shortly say 'that if it occurred during the Shechitah it is different ...

Refutation (Part 1): ... seeing as it becomes revealed that retroactively there was no Shechitah at all ...

Refutation (Part 2): ... because since it became spoiled, it transpires that nothing was performed for the sake of the Parah be'Kashrus ...

Conclusion: ... whereas if a P'sul occurred with the Haza'ah, it doesn't matter, seeing as the Shechitah was already performed be'Kashrus.

Question (Part 1): It is clear that the prohibition of two people Shechting one Korban is speaking Lechatchilah, and that it is Kasher Bedi'eved

Precedent: ... just like where one person Shechts two Korbanos, like we learned on the previous Amud, when we established the Mishnah of 'ha'Shochet Sh'nei Roshim ke'Echad, Shechitaso Kesheirah' by Kodshim.

Question (Part 2): If so, why don't we draw a distinction by the Hechsher of the Parah?

Answer: Since Lechatchilah it is forbidden, it falls under the category of 'something that is not common' (which the Tana does not generally discuss).

Implied Question: Even though the Gemara asks 'why it is does not draw a distinction in a case concerning two head-scarves (which is also not common) ...

Answer: ... that is more common (than two people Shechting one Korban).