And one who wishes to adopt both the stringencies of Beit Shammai and the stringencies of Beit Hillel, with regard to him the verse states: “The fool walks in darkness” (Ecclesiastes 2:14). Rather, one should act either in accordance with Beit Shammai, following both their leniencies and their stringencies, or in accordance with Beit Hillel, following both their leniencies and their stringencies.

The Gemara objects to the wording of the baraita: This baraita itself is difficult. First you say that the halakha is always in accordance with the statement of Beit Hillel, and then you teach that one who wishes to act in accordance with the statement of Beit Shammai may do so.

The Gemara responds: This is not difficult. Here, the statement that a person may act as he wishes was made before the Divine Voice emerged and announced that the halakha is always in accordance with Beit Hillel. There, the statement that the halakha is always in accordance with Beit Hillel was made after the Divine Voice issued this ruling.

And if you wish, say instead that even the statement that a person may act as he wishes was made after the Divine Voice announced that the halakha is in accordance with Beit Hillel, and this statement is in accordance with the opinion of Rabbi Yehoshua, who says: One disregards a Divine Voice that attempts to intervene in matters of halakha. According to him, the dispute between Beit Shammai and Beit Hillel has not yet been decided.

The Gemara notes: In any case, Rava’s ruling is difficult. How could he rule in accordance with two contradictory stringencies in order to deem the animal a tereifa?

Rav Tavut said: Rava acted entirely in accordance with the opinion of Rav. As when Rami bar Yeḥezkel came, he said: Do not listen to those principles that Rav Yehuda, my brother, formulated in the name of Rav. Although Rav holds that a perforation of any part of the entrance of the gullet renders an animal a tereifa, this is not because it is a location fit for slaughter. Rather, this is what Rav said: The Sages gave a measure defining the portion of the gullet that is valid for slaughter. By inference, one learns that the entrance of the gullet is not a location fit for slaughter. And nevertheless, he says that a perforation in any amount renders the animal a tereifa.

Since it was mentioned that the Sages gave a measure defining the portion of the gullet that is valid for slaughter, the Gemara asks: How far up the gullet is the upper boundary for valid slaughter? Rav Naḥman said: It is until the point that there remains only sufficient space for a hand to grip the gullet. The Gemara asks: How far down is the lower boundary? Rav Naḥman said that Rabba bar Avuh said: Until the gullet becomes hairy, i.e., until the opening of the rumen, whose lining is hairy.

The Gemara asks: Is that so? But doesn’t Ravina say that Geneiva says in the name of Rav: The lowermost handbreadth in the gullet, adjacent to the rumen, this is the inner rumen? If so, why does Rav Naḥman permit slaughter until the opening of the rumen? When one slaughters within the bottom handbreadth, he is slaughtering in the rumen, and his slaughter should be invalid.

Rather, say that Rav’s statement should be amended, as follows: The uppermost handbreadth in the rumen, adjacent to the gullet, this is the inner rumen, which is not a valid location for slaughter. By contrast, the lowermost handbreadth of the gullet is a valid location for slaughter. And if you wish, say instead that when Rav says that the lowermost handbreadth of the gullet is considered the rumen, he is referring specifically to a bull, which is especially hairy, and hairs appear even within the lowermost handbreadth of the gullet itself. By contrast, in other animals, the entire lower gullet is a valid location for slaughter.

§ Rav Naḥman says that Shmuel says: If the entrance of the gullet was completely detached from the jaw, the animal is kosher. And the tanna of the mishna also taught this later (54a): If the lower jaw was detached entirely, it is kosher.

Rav Pappa objects to this: How can Shmuel say that if the entrance of the gullet is detached the animal is kosher? But isn’t there ripping of the simanim, the gullet and the windpipe, from their place? This should render the animal a tereifa.

The Gemara interjects: But according to Rav Pappa, the mishna is difficult as well, since it states: If the lower jaw was detached, it is kosher. If the lower jaw is detached, the windpipe and gullet will necessarily be detached as well, since they are attached to it.

The Gemara responds: Granted, the mishna is not difficult for Rav Pappa. This halakha, that the ripping of the simanim renders the animal a tereifa, applies only when the simanim are completely ripped from the jaw. That statement of the mishna, that an animal whose jaw is detached is kosher, is referring to a case where the lower jaw is severed above its connection to the simanim, which themselves remain connected to the remaining flesh of the jaw. But the halakha that the ripping of the simanim renders the animal a tereifa is difficult for Shmuel. How can an animal remain kosher when the entrance of its gullet is removed, if this entails the ripping of the simanim?

The Gemara responds: Do not say that Shmuel deems the animal kosher if the entrance of the gullet was completely detached. Rather, say that he deems it kosher only if it was mostly detached.

The Gemara asks: But doesn’t Rabba bar bar Ḥana say that Shmuel says: Simanim that were detached in their majority render the animal a tereifa? Rav Sheisha, son of Rav Idi, said: This statement of Shmuel, that the animal is kosher even if the simanim are mostly detached, applies only to a case in which the entrance of the gullet was peeled off from the flesh of the jaw, such that the connected tissue is concentrated in one area. In such a case, the animal might recover. There, where Shmuel deems the animal a tereifa, he is referring to a case in which the simanim were forcibly separated [de’ippruk ipprukei] from the jaw and are connected only by a few discontinuous pieces of flesh. In such a case the animal cannot recover.

§ The mishna states: Or an animal with a cut windpipe, cut across its width, is a tereifa. With regard to this the Sages taught: How much must the windpipe be cut to render the animal a tereifa? In its majority. And how much is its majority? Rav says: