Explanation #1 (Rashbam): All the more so, in our Mishnah, that he willingly gave to them (they keep the path).

Afterwards, [we ask] according to Rabah bar Rav Huna, who says that the Halachah does not follow [R. Eliezer], what is the reason [for the Mishnah]?

Explanation: Obviously, he does not establish our Mishnah according to R. Eliezer, and unlike the Halachah. Like whom does he establish it?

Question #1 (Ri): In Bava Kama (28a) we do not bring Rav Gidal's teaching, and not Rabah bar Rav Huna's;

[There] we explain the reason for our Mishnah here due to Rav Yehudah. This implies that all agree that this is the reason for our Mishnah!

Question #2 (Rashba): If according to Rav Gidal the reason for our Mishnah is understood, for it is like [a path] that was lost, also according to Rabah bar Rav Huna we should not ask, for he agrees about a lost path, that what they chose, they chose (they keep)!

Question #3: (The Rashbam) explained that all the more so, in our Mishnah (they keep the path). This is wrong. In our Mishnah, no matter what you will say, they have a path illegally;

However, when a path was lost, no matter what you will say, they have a path in his property!

Proof: The Gemara asks "if so, why did Rabah say that the Halachah does not follow R. Eliezer?" This shows that when it was lost, it is obvious to him that they have a path;

Above, we questioned our Mishnah "he should say to them 'take yours, and give to me mine!'"

Explanation #2 (Ri): Initially, we conclude that our Mishnah is like R. Eliezer. At the end, when we answer that [the path] was lost, our Mishnah is not like R. Eliezer.

Support: We find like this in Gitin (51a) in the Sugya of "you found two tied wallets of mine."

Below, the text does not say "according to Rabah bar Rav Huna, who says that the Halachah does not follow...", for everyone must explain the reason for our Mishnah like Rav Yehudah.

Explanation #3: We say "who [taught our Mishnah]? It is R. Eliezer", like we conclude. R. Eliezer discusses when [a path] was lost, and our Mishnah resembles the case of a lost path, like [the Gemara] explains the reason afterwards;

Rabanan who argue with R. Eliezer about an Aveidah, and say that their choice [of a path] does not help at all, argue also with our Mishnah. We do not say that what he gave to them, he gave;

According to Rabah bar Rav Huna, who holds that Rabanan do not argue about a lost path, our Mishnah is like everyone;

At the end, we ask "what is the reason?..." Why is our Mishnah like a lost path?

Because R. Eliezer said about a lost path that what they chose, they keep, we should say so also in our Mishnah! We conclude that [our Mishnah is due to] Rav Yehudah.

Explanation: "They chose a path" connotes without fixing anything, just through mere choice.

Explanation: This is only for a path in a vineyard, which is not used at all, just for walking;

However, another [kind of] path is made somewhat for other needs.

Suggestion: [Mesaimei] means that the walls are tall.

Rejection: If so, how can he carry a load [of vine sprigs and turn around]?!

Explanation: Rather, the walls are low, e.g. one or two Tefachim to demarcate the path;

Therefore, when he sold to him the path in his field, he gives to him only like it is made, even if it is [wide enough] only to lift a foot and place [the other] foot (there is not room for two feet side by side).

This forced the Rashbam to reject this text, for he holds that the walls are very tall.

Explanation #1 (Rashbam): [A normal] Mes is three Amos long. Due to [the thickness of the walls of] the coffin, we need another Amah.

Rebuttal: In Shabbos (92a), it explicitly connotes that a person is three Amos tall until the shoulders!

Citation (92a): The Aron was nine Tefachim tall, and the Kapores (its cover) was a Tefach thick, so there is 10 (total height), and we have a tradition that any load carried on poles, [it is proper that] a third is above and two thirds is below;

Citation (cont.): It turns out [the entire Aron] was above 10 Tefachim, for from the shoulders until [the ground] below is 18 Tefachim, and two thirds [of the height of the Aron] is six and two thirds Tefachim. It turns out [the bottom of the Aron] was 11 and a third Tefachim [above the ground].

Summation of rebuttal: If until the head is only 18 Tefachim (three Amos, the Aron) was not above 10, for from the [top of] the head until the shoulders is much more than one and a third Tefachim!

Support (for rebuttal): The Targum of Megilas Esther (9:14) says that the hanging of Parshandasa (the first son of Haman) spanned three Amos, and the heads [of Haman's sons] were cut off.

Explanation #2: The burial cavities were four Amos long. [The extra Amah was] due to the neck, head and [thickness of] the walls of the coffin.

Explanation (Rashbam): This is so there will be an [empty] cubic Tefach in the coffin, so the Tum'ah will not break through it and go up and be Metamei one who passes over it.

This is like [R. Eliezer bar Tzadok, who was a Kohen] said in Brachos (19b) "we used to jump over coffins [in order to see kings]";

There, it explains that the reason is because most coffins have an [empty] cubic Tefach.

Observation: However, [the empty cubic Tefach] helps only for Tum'ah mid'Oraisa. Mid'Rabanan, one who passes over it is Tamei, like it says there that they decreed about this;

They permitted [Kohanim to pass over] only to go to the place of a Mitzvah, e.g. to greet kings.

Explanation (Rivam): Their burial cavities were open from the side, for they placed the Mes inside [from the side];

If they were sealed, the Tum'ah would break through and go up. Just the contrary, there is more Tum'ah when there is an empty cubic Tefach, since it is sealed!

If there were no empty cubic Tefach, the Tum'ah would break through and go up only directly in line [with the Mes]. Now that there is an empty cubic Tefach, it is as if the entire length and width is full of Tum'ah, and the Tum'ah breaks through and goes up even not in line with the Tum'ah! (Maharam - the Tum'ah breaks through and goes up unless there is a empty cubic Tefach, and it is open from the side. Mid'Rabanan, we decreed lest there is not an empty cubic Tefach, so always the Tum'ah breaks through and goes up.)

Support (Rivam): We learn from above (12a. If Tum'as Mes is inside a sealed house, only the doorway becomes Tamei.) If he removed the doorposts and lintel (it is like a sealed grave), all around the house is Tamei;

It is Metamei through touching mid'Oraisa, one who touches anywhere around the house, even though the Mes does not fill the entire house.

Presumably, similarly it is Metamei on top, even though there is an empty cubic Tefach. It is not proper to elaborate here.

Question: Since they decreed about a grave, even if there is an empty cubic Tefach, also in a house, even if he did not remove the doorposts and lintel (so it is like a grave open on the side), it should be Metamei in line with the Tum'ah!

Just like a sealed house has the law of a sealed grave, also an open [house] should have the law of an open grave!

Answer: Regarding a grave they decreed about a coffin with an empty cubic Tefach due to one without. However, there is no house without an empty cubic Tefach, and they did not want to decree a house due to a grave. (Rashash - however, when he removed the doorposts and lintel, it is Metamei all around and above mid'Oraisa, like a sealed grave, like Tosfos said above.)

Proof #1 (Ri): [Rivam said that] if [the grave] is sealed, even if there is an empty cubic Tefach, the Tum'ah breaks through and goes up. We learn from a Beraisa (Nazir 53b). "Oh b'Kever" includes a sealed grave;

Inference: Since it says sealed, and not open, there is an empty cubic Tefach, and even so we include a sealed grave. (If there was not an empty cubic Tefach, whether it is sealed or open, only above the Tum'ah is Tamei.)

Question (Ri): [Rivam] explained that if there is not an empty cubic Tefach, [the Tum'ah] breaks through and goes up only in line with the Tum'ah. What is his source?

In every case the verse includes a sealed grave, that it is Metamei all around and on top, even if there is no empty cubic Tefach! (Rashash - in Brachos (19b DH Rov), Tosfos brought a source from Ohalos 7:1.)

Proof #2 (that Tum'ah breaks through a sealed grave even if there is an empty cubic Tefach): A Mishnah in Ohalos (3:7) says that if there is a covered Biv (sewer) under the house, and it has an empty cubic Tefach, and where it exits there is a [square] Tefach, if there is Tum'ah in the Biv, the house is Tahor. If there is Tum'ah in the house, the Biv is Tahor;

If the Biv has an empty cubic Tefach, and where it exits there is not a [square] Tefach, it is considered sealed. Even though it has an empty cubic Tefach, [the Tum'ah] breaks through and goes up.

Question #1 (Ri): The Mishnah in Ohalos (4:2), brought in Chulin (125b) says that if a box or tower has an empty cubic Tefach, and where it exits there is not a [square] Tefach, if there is Tum'ah in the box, the house is Tamei. If there is Tum'ah in the house, the box is Tahor, because it is normal for Tum'ah to leave, and not to enter.

Explanation: It is normal [for Tum'ah] to leave the chests and tower through the house.

Summation of question: Why do we need the reason that it is the way of Tum'ah to leave? Even without this, it breaks through and goes up, since where it exits there is not a Tefach!

Also, why does R. Yosi argue there and he is Metaher, because he can take it out in halves, i.e. a half-k'Zayis, which is not Metamei b'Ohel, or because he can burn it in its place?

Question #2: Also, the Seifa teaches "if he stood [the tower] at the opening [of the house] - if the opening [of the tower] faces outside, if the Tum'ah is inside [the tower], the house is Tahor. What is the reason? The Tum'ah breaks through and goes up!

Answer: In Kelim, there is no law of a grave that it breaks through and goes up, for he is not Mevatel it (i.e. designate the Kli for the need of the Tum'ah).