Opinion #1: Rashi always explains "Golel" as meaning the cover of a coffin of a dead person, and he explains "Dofek" as meaning a plank that is on the side of the coffin. It is called a Dofek because the dead person knocks into it.

Proof: This is like the terminology used in Bava Metzia (23b) when the Gemara asks that the type of piece found should be a Siman, such as whether it is from the flank (see Maharsha) or the thigh. The flank is called a Dofek because the breath drawn by the animal knocks against the flank.

Question #1: This does not appear to be correct according to Rabeinu Tam, as the Gemara in Berachos (19b) says, "We used to skip over coffins to greet the kings of the nations of the world."

Question #1 (cont.): If a coffin is a Golel and Dofek, how did they skip over it? A Golel and Dofek would cause impurity through Ohel! This is as the Gemara in Chulin (126b) states that a Golel and Dofek cause impurity through touch and Ohel, but not through carrying them.

Question #2: Additionally, the Gemara in Eruvin (15b) says that any living thing cannot be made into a Golel for a grave, a wall of a Sukah, or a pole of an alleyway. According to Rashi, is it normal to make a cover of a grave out of living animals?!

Question #3: Additionally, in Chulin (72a) we include Dofek as causing impurity from the Pasuk, "on the face of the field." According to Rashi it is in the ground, as it is part of the coffin, and not on the field.

Question #4: Additionally, the Mishnah in Ohalos (2:4) says, "Dofek Dofkim Tahor." If Rashi's explanation is correct, is it normal to place two planks on the right side of the dead person?!

Opinion #2: Rabeinu Tam explains that a Golel is a large stone that is on the coffin of a dead person known as a headstone. The relatives of the deceased roll it to the location of the grave to mark the grave. The word "Golel" applies to a rock, as the Pasuk states, "v'Gililu" - "And they rolled the stone" (Bereishis (29:3). Similarly, the Pasuk states, "And one who rolls a stone it will come back to him" (Mishlei 26:27).

Opinion #2 (cont.): A Dofek is two stones that are placed by the grave, one at the head and one at the feet, in order to mark the grave. Sometimes, since the intended stone(s) has not yet been (found and) prepared for this purpose, an animal or other item is placed there as a temporary marker until they find a proper stone. This is why the Gemara in Eruvin (15a) says that a live animal cannot be made into a Golel etc.

Opinion #2 (cont.): Regarding skipping over coffins, the case is where there were no markers at all that were present. They did not become impure due to the dead body that was lying there, as explained there, that most coffins used at that time had a space of one Tefach between the dead body and the roof of the coffin. It is also understandable (according to Rabeinu Tam) why Golel and Dofek are included from the Pasuk, "on the face of the field" (as they are indeed on the field, not under the ground).

Opinion #2 (cont.): The Mishnah in Ohalos regarding Dofek Dofkim is referring to the fact that sometimes the Golel is placed on two stones. Additionally, they sometimes put one stone at the head of the Golel and one at the other end.

Implied Question: One should not ask a question on Rabeinu Tam from the Gemara in Kesuvos (4b) where Rebbi Yehoshua says, "When does Aveilus start? It starts when the Golel is closed. When there is no Golel, when does it start?" (This implies that a Golel is the cover of the coffin!)

Answer: It is possible to answer that this refers to when they turn away from the grave. This is as stated in Moed Katan (22a) that the ones who do not follow the procession carrying the dead person to his grave start to count from when they turn their face away from the body.

Question: Some push aside the proof of Rabeinu Tam by saying that there is no proof just because people used to skip over coffins (to see kings, as stated in Berachos 19b). Even though the Golel causes impurity through Ohel, they were allowed to skip over it and become impure.

Proof: This is as the Beraisa states in Meseches Semachos (4:21) that any impurity that a Nazir does not have to shave because of a Kohen is not warned (by the Torah) that he must stay away from it. Impurity from a Golel and Dofek do not cause a Nazir to shave, as stated in the Mishnah in Nazir (54a).

Answer: Rabeinu Tam says that the Beraisa in Meseches Semachos (ibid.) is inaccurate.

Proof: This is evident from a long discussion in the Gemara regarding a Nazir not having to shave due to becoming impure from a Revi'is of blood, as stated in the Mishnah in Nazir, and yet a Kohen is obligated not to become impure through a Revi'is of blood. If the Beraisa from Meseches Semachos would be quoted in our Gemara, the Gemara would have asked questions on it and established it as being inaccurate, as we find in many places that when inaccurate Beraisos are quoted in the Gemara.

Answer (cont.): Even if the Beraisa is correct, how could they have skipped over the coffins? They would become impure due to the dead body, and the Golel and Dofek would not be an impediment that would stop the impurity from the body from making them impure!

Question #1: Some question Rabeinu Tam's proof from Eruvin by saying that even though it is uncommon to make a cover for a coffin from a living animal, we find many things that are uncommon and that the Gemara discusses despite their rarity in order to show us a (theoretical) law and in order that we should receive reward (for delving into Torah).

Proof: This as stated in Chulin (70a) that if a weasel swallowed it (a firstborn that had not yet been born), and by doing so took it out of its mother's womb, ate it and threw it up, and then it left his body, is it considered a firstborn? If a person took two wombs of animals and a (potential) firstborn went from one to the other, what is the law? The Gemara discusses these things, despite the fact that they will never happen.

Question #2: We also ask according to Rabeinu Tam's explanation that the Tosefta in Ohalos (3:10) says that if there were two big stones that were made into a Golel for a grave, a person who hovers over both of them is considered impure. If one of them was taken away, a person who hovers over the other one is pure because the impurity has a way to exit. According to Rabeinu Tam's explanation of Golel, how does it make sense to say that the impurity has a way to leave?

Opinion: The Aruch gives a different explanation for the word "Golel," which makes the Tosefta (ibid.) more understandable.