1) WHY THE KOHEN GADOL DOES NOT WEAR THE TZITZ ON YOM KIPPUR
QUESTION: Rebbi Shimon asserts that the Tzitz is Meratzeh (appeases) for Tum'ah that occurs in the Mikdash even when the Kohen Gadol is not wearing it. He proves this from the fact that the Korbanos of Yom Kippur may be brought in a state of Tum'ah (when the entire nation is Tamei), even though the Kohen Gadol does not wear the Tzitz during the Avodah of Yom Kippur. If the Tzitz is not Meratzeh when it is not worn, then how can Korbanos be brought in a state of Tum'ah on Yom Kippur? It must be that the Tzitz is Meratzeh even when it is not worn.
RASHI explains that when Rebbi Shimon says that the Tzitz is not worn during the Avodah of Yom Kippur, he means that it is not worn during the "Avodas Penim," the "inner Avodah," the Avodah that is performed inside the Kodesh ha'Kodashim. While he performs that Avodah, he does not wear the eight garments that a Kohen Gadol normally wears (which include the Tzitz), but only four garments. Rashi explains why the other four garments are not worn during the Avodas Penim on Yom Kippur. The Gemara in Rosh Hashanah (26a) says that the four other garments that are not worn on Yom Kippur contain gold, and when the Kohen Gadol goes into the Kodesh ha'Kodashim on Yom Kippur we do not want the gold in the garments to act as a prosecutor against us for the sin of the Golden Calf -- "Ein Kateigor Na'aseh Saneigor" ("a prosecutor cannot become a defense attorney").
REBBI AKIVA EIGER (in Gilyon ha'Shas) points out that this is an odd way for Rashi to explain the Gemara. Rashi should explain simply that that the Tzitz is not worn on Yom Kippur because the verse in the Torah (Vayikra 16:4) states that only four linen garments are worn by the Kohen Gadol on Yom Kippur. The Gemara in Rosh Hashanah that Rashi quotes merely gives a homiletical reason for why the golden vestments are not worn. The reason why the Tzitz is not worn during the Avodas Penim is not relevant to the discussion of the Gemara here.
ANSWER: Perhaps we can better understand the words of Rashi based on an insight of the MIKDASH DAVID (Kodshim 36:1). The Mikdash David points out that the Gemara in Zevachim (19b) states that the Kohanim, including the Kohen Gadol, wear the Tefilin Shel Rosh upon their heads together with the Bigdei Kehunah, the priestly garments. The Tefilin is not considered a Chatzitzah, an invalid separation, between the Kohen's body and his priestly garments, because it is not worn on a part of the body where the priestly garments are worn. It is also not considered Yitur Begadim, wearing additional, unauthorized items of clothing, which is forbidden when the Kohen performs the Avodah. Why is the Tefilin not considered an extra item of clothing? TOSFOS there (19a, DH Tefilin) suggests that the Gemara maintains that the Tefilin is not considered Yitur Begadim when the additional garment is not worn in the place where a priestly garment is worn. Alternatively, the Tefilin is not considered a "garment," presumably because it is not made of cloth and it is not worn to protect the body. Rather, it is like a decorative adornment.
The Mikdash David asks that according to the Gemara in Zevachim, what is Rebbi Shimon's proof that the Tzitz is Meratzeh even when it is not worn? Perhaps it is not Meratzeh when it is not worn, but Korbanos may still be brought in a state of Tum'ah on Yom Kippur, because the Tzitz may be worn during the Avodas Penim! If the Kohen Gadol decides to don the Tzitz for the Avodas Penim, it should not be considered Yitur Begadim, just as the Tefilin is not considered Yitur Begadim. Once the Kohen wears the Tzitz, it is Meratzeh for Tum'ah.
The Mikdash David answers that the Gemara in Rosh Hashanah teaches that the Kohen Gadol is not allowed to wear the golden vestments when he enters the Kodesh ha'Kodashim, because of the rule of "Ein Kateigor Na'aseh Saneigor." This is the reason why the Kohen Gadol may not wear the Tzitz, even though it is not considered Yitur Begadim.
Perhaps this is Rashi's intention. Rashi is addressing the question, how does Rebbi Shimon know that the Kohen Gadol may not wear the Tzitz? Although the Kohen Gadol is not obligated to wear it on Yom Kippur (as the verse says), perhaps he is permitted to wear it, and when he wears it, it is Meratzeh. Rashi explains that not only is the Kohen Gadol not obligated to wear the Tzitz, he also is not permitted to wear it -- because of the reason of the Gemara in Rosh Hashanah. Accordingly, Rebbi Shimon's assertion that the Tzitz is Meratzeh even when it is not worn is correct. (M. KORNFELD)
Why does Rebbi Akiva Eiger not accept this answer? Perhaps he found support for his question in the TORAS KOHANIM (Vayikra 16:4). When the verse lists the four linen garments that the Kohen Gadol wears on Yom Kippur, it says the word "linen" ("Bad") next to each of the four garments. The Toras Kohanim derives from these repetitive mentions of the word "linen" that the verse intends to exclude four other garments and to teach that they are not worn. Consequently, Rashi does not have to mention the reason of "Ein Kateigor Na'aseh Saneigor" to explain why the Kohen may not wear the Tzitz, but rather the Derashah in the Toras Kohanim.
However, this question is not such a strong one. Perhaps the Toras Kohanim means simply that we might have thought that the other four garments must be worn on Yom Kippur (as the verse says with regard to those garments, "Lifnei Hash-m Tamid" -- "one must wear them before Hash-m always," Toras Kohanim ibid.), and therefore the Torah teaches that they do not have to be worn. The only reason why the Tzitz may not be worn is because of "Ein Kateigor Na'aseh Saneigor," as Rashi says.
Alternatively, perhaps Rebbi Akiva Eiger understands that when there is no obligation to wear the Tzitz, the Tzitz does not serve to be Meratzeh. Therefore, even if the Kohen Gadol wears it on Yom Kippur, it will not be Meratzeh since he has no obligation to wear it.
However, this approach to understanding Rebbi Akiva Eiger's question is also difficult. Rebbi Yehudah, who argues with Rebbi Shimon and maintains that the Tzitz is Meratzeh only while the Kohen Gadol wears it, certainly maintains that it is Meratzeh even when the Kohen Gadol is not performing Avodah at the time. When the Kohen Gadol is not performing the Avodah, he certainly is not obligated to wear the Tzitz, and, according to some opinions, he does not even fulfill a Mitzvah when he wears it, and yet it is still Meratzeh. We see, therefore, that even when the Kohen Gadol wears the Tzitz when he has no obligation to wear it, it is Meratzeh.
2) WHY IS "TUM'AH DECHUYAH B'TZIBUR" IF THERE IS "RITZUY TZITZ"
QUESTION: The Gemara teaches that the principle of Tum'ah Dechuyah b'Tzibur, which permits the Tzibur to offer Korbanos while in a state of Tum'ah, does not function unless there is also Ritzuy Tzitz (the conciliatory effects of the Tzitz) at the same time. The Tzitz is Meratzeh (appeases) for the Tum'ah of Kodshim, and the principle of Tum'ah Dechuyah b'Tzibur allows the Avodah to be done.
If there exists Ritzuy because of the Tzitz, why is there a need for the principle of Tum'ah Dechuyah b'Tzibur to permit the Tzibur to do Avodah while Tamei? Ritzuy Tzitz alone should permit the Avodah to be done while the Tzibur is Tamei. Moreover, even an individual should be permitted to offer a Korban while Tamei because of Ritzuy Tzitz.
(a) Perhaps the Tzitz is Meratzeh for an individual only b'Di'eved (that is, when the Avodah was already done in a state of Tum'ah; see Mishnah, 80b). For the Tzibur, the Avodah may be done even l'Chatchilah while the people are Tamei, because of the principle of Tum'ah Dechuyah b'Tzibur.
The BRISKER RAV (end of Maseches Nazir, p. 180) writes that whether the Ritzuy of the Tzitz is l'Chatchilah or only b'Di'eved appears to be the subject of a disagreement among the Rishonim. The RAMBAM (Hilchos Ma'aseh ha'Korbanos 8; see also Hilchos Bi'as ha'Mikdash 4:6) implies that it is effective only b'Di'eved. TOSFOS (80b, DH Nizrak) understands that the Tzitz permits the Avodah to be done while one is in a state of Tum'ah even l'Chatchilah. (This may also be the understanding of Rashi to Pesachim 79a, DH u'Mashvi.)
(b) TOSFOS (78a, DH Ha) answers that the principle of Tum'ah Dechuyah b'Tzibur is necessary because there are certain types of Tum'ah for which the Tzitz cannot be Meratzeh, such as Tum'as ha'Guf (when the Kohanim who bring the Korban are Tamei). In such a case, the Tzitz does not help, because it is Meratzeh only for meat, blood, or fats that became Tamei (Mishnah, 80b; see Insights there). In such situations it is the principle of Tum'ah Dechuyah b'Tzibur that permits the Tzibur to offer Korbanos while in a state of Tum'ah, even without the conciliatory effects of the Tzitz.