Chullin 96: What does Rav Pappa mean that Shmuel's position is a matter of Tannaitic dispute?

In today's daf yomi (Chullin 96a, going on to b), Shmuel had a position that only that portion of the sciatic nerve which was over directly the spoon of the thigh was prohibited. And Rav Pappa says:

אמר רב פפא כתנאי אכלו ואין בו כזית חייב רבי יהודה אומר עד שיהא בו כזית

That is, while the Mishna did not have Rabbi Yehuda argue regarding whether one who ate a full gid hanasheh was liable, in a brayta Rabbi Yehuda does argue. And, somehow, one unspecified side of this argument lines up with Shmuel's position limiting the (Biblically) prohibited area of the gid.

Rashi explains it as follows:

אמר רב פפא כתנאי - כדמפרש ואזיל דרבנן אית להו דשמואל ורבי יהודה לית ליה דשמואל

This is indeed a faithful rendition of the conclusion of the gemara, that the side in the machlokes who holds like Shmuel is the Rabbanan (=Rabbi Meir, I think), and it is not in accordance with Rabbi Yehuda.

The gemara which follows bears the clear mark of authorship by the setama degemara. It is a derasha chain. This Tanna interprets this pasuk in this way. So how does the opponent interpret the verse? And if so, where does the first Tanna derive that law? And so on, until the game of musical chairs ends. This is a systematic approach to derashot that one often finds in the setama.

And the way it operates here is that Rabbi Yehuda requires "asher al kaf hayarech" to derive a specific law, while the Rabbanan utilize that verse for Shmuel's derasha. So, even though the specifics of the dispute between Rabbi Yehuda and the Rabbanan about eating a berya of gid less than a kezayit have little semantically to do with Shmuel's identification of the prohibited gid, it turns out that the two positions are related because of competition for the verse each is derived from.

Besides being somewhat awkward and surprising, in the sense that Rav Pappa should really have been much clearer in how these relate, there are difficulties in the derasha chain itself. In particular (96b), we have to believe that Rabbi Yehuda holds that the presence of the word achila in the pasuk indicates that it must be a kezayit, and a berya does not suffice, even though (as Tosafot points out), in all other places, one is liable for a berya (such as an ant) even less than a kezayit, and there is no indication that Rabbi Yehuda disagrees there. Tosafot's question is better than any answer. And the Rabbanan's rejoinder, that the word achila is to indicate that one is liable even if there are multiple olive measures and he only ate one is also suspect. Would one say that one is liable only if he ate all the cheilev?

My resolution of Rav Pappa is against what is explicit in the setama degemara, but I think that it makes sense. Shmuel's position is in accordance with Rabbi Yehuda, not the Rabbanan. Here is how.

If the entire gid is forbidden, then it makes sense to say that eating a berya, meaning a complete forbidden entity, makes one liable, even if that whole entity is less than a kezayit. But if you tell me that only a small portion of the entity is forbidden, one cannot label it a berya. If only the cheilev of the ant were forbidden, eating a whole ant that includes that cheilev is not berya. And eating just all that forbidden portion is also not berya.

Therefore, since Shmuel holds that only a small subsection of the gid, namely that over the spoon of the thigh, is forbidden, Rabbi Yehuda would say that there is no aspect of berya here for eating that entire forbidden entity. The forbidden part of the gid is not a complete entity in and of itself. Therefore, the Rabbanan who maintain that it is indeed a berya for less than a kezayit could not hold that only a small portion of the gid is forbidden, and argue upon Shmuel.

How could Yaakov Avinu go out at night?

A few days ago, in daf yomi (Chullin 91a), we saw that one a Torah scholar should not go out alone at night, and that this is derived from the case of Yaakov, who went out alone after his small vessels at night.

(בראשית לב, כה) ויאבק איש עמו עד עלות השחר אמר רבי יצחק מכאן לת"ח שלא יצא יחידי בלילה

As Rashi explains, they wrestled until dawn, showing that mazikin cannot harm during the day, such that he would not need shemira during the day.

מדקאמר עד עלות השחר - שמע מינה לא ניתנה רשות למזיק להזיק ביום לפיכך לא הוצרך שמירה:
מכאן לתלמיד חכם כו' - שהרי יעקב נשאר יחידי והוזק:

Someone in the shiur asked how Yaakov could go out alone at night. After all, the avot kept the entire Torah. (And, I would add, the gemara just above sort-of endorsed this idea, stating that Yosef in disguyise commanded that his brothers be able to see the bet hashechita as well as that the gid hanasheh was removed.) How could Yaakov go out alone at night, when the gemara says that a Talmid Chacham should not go out at night?

My answer is this: Where is this halacha derived from, if not this very incident! What if Yaakov tried to keep this halachah, and did not go out at night? Then, the incident would not have happened and the gemara could not have derived the halachah. In which case, Yaakov would not have known not to go alone out at night.

More than that, not going out alone at night would have created a temporal paradox which could have destroyed the entire universe! Therefore, Yaakov had no choice but to go out alone at night and subject himself to danger.