1) DESTROYING TERUMAH TEHORAH
QUESTIONS: Rebbi Yehoshua and Rebbi Elazar argue about what to do with a barrel of Terumah when it is not known whether or not the Terumah became Tamei (it is "Terumah Teluyah"). Rebbi Yehoshua says that it may be put out in the open and left unprotected. Rebbi Elazar says that it still must be protected from Tum'ah.
The Gemara (15a) explains that the opinion of Rebbi Yehoshua is not the source for Rebbi Meir's teaching in the Mishnah. Rebbi Meir states that when one destroys Chametz before Pesach, he may burn Terumah Tehorah with Terumah Teme'ah. Rebbi Yehoshua does not permit one to destroy Terumah Tehorah actively; he merely permits one to let the Terumah become Tamei indirectly by leaving it out in the open (through an act of "Gerama," indirect causality). Rebbi Meir, though, permits the active destruction of Terumah Tehorah.
RASHI (15b, DH Hachi Ka'amar), however, gives a different explanation for why the opinion of Rebbi Yehoshua cannot be the source for Rebbi Meir's teaching. Rashi addresses the opinion of Rebbi Yosi, who disagrees with Rebbi Meir in the Mishnah and says that one is not allowed to burn Terumah Tehorah on Erev Pesach. Rebbi Yosi says that we cannot learn from Rebbi Yehoshua's ruling that Terumah Teluyah may be left out in the open that it is permissible to burn Terumah Teluyah or Terumah Tehorah on Erev Pesach, because in Rebbi Yehoshua's case, the Terumah Teluyah might already be Tamei. Therefore, one's act of "Gerama" might not be making it Tamei. In the case of Rebbi Meir, though, the Terumah is definitely Tahor and one is actively making it Tamei.
(a) Why does Rashi not suggest the reasoning that the Gemara itself mentions earlier? Rashi should explain that Rebbi Yosi disagrees with Rebbi Meir because from Rebbi Yehoshua's statement we see only that one may indirectly let Terumah become Tamei, but not that one may actively make it Tamei and destroy it. (BEIS MEIR)
(b) Rashi asserts that the case of burning Terumah Tehorah before Pesach cannot be compared with Rebbi Yehoshua's ruling that Terumah Teluyah may be left to become Tamei, because in Rebbi Yehoshua's case, the Terumah Teluyah might already be Tamei. Why does the Gemara earlier (15a) not give that reason? (RASHASH)
(a) The BEIS MEIR explains that, according to Rashi, Rebbi Yosi objects to the comparison between Rebbi Yehoshua's opinion and Rebbi Meir's opinion for a reason other than the reason the Gemara mentions. Rebbi Yosi objects not because in the case of Rebbi Yehoshua one's act is a "Gerama," and in the case of Rebbi Meir it is a direct act. Rather, Rebbi Yosi argues that in the case of Rebbi Yehoshua, the Terumah is Terumah Teluyah that one makes Tamei, and in the case of Rebbi Meir the Terumah is definitely Tehorah.
(b) The Gemara could not have challenged Rebbi Meir's ruling by saying that Rebbi Yehoshua said his ruling only with regard to Terumah Teluyah, because it is clear from the Mishnah itself that Rebbi Yosi is the only one who differentiates between Teluyah and Tehorah. This implies that Rebbi Meir maintains that this difference is insignificant, and that he views Teluyah to have the same status as Tehorah (since Eliyahu ha'Navi might come and reveal to us that it is Tehorah, as the Beraisa earlier mentions). Therefore, when the Gemara discusses the view of Rebbi Meir, the only objection to the comparison between Rebbi Yehoshua's ruling and Rebbi Meir's ruling is that Rebbi Yehoshua's case involves "Gerama," and Rebbi Meir's case involves a direct act. It is only Rebbi Yosi who objects to the comparison on the grounds that in one case the Terumah is Teluyah, and in the other it is Tehorah.