1) THE DIFFERENCE BETWEEN A LOT OF "KALON" AND A LITTLE "KALON"
OPINIONS: The Mishnah earlier (54a) teaches that if a Jew is put to death for having relations with an animal, the animal is also killed. Rav Sheshes was asked whether the animal is killed when the person who sinned with it is a Nochri. If the reason for killing the animal when a person sinned with it is that it was a "Takalah" (a stumbling block; the animal is the object which caused a person to sin and be killed) and "Kalon" (the sin causes great shame), then the animal is not killed when the sinner is a Nochri, since such an act is not as shameful to Nochrim as they are to Jews. However, if the reason for killing the animal is solely due to the fact that it was a "Takalah" for a very severe sin, the Nochri's sin is also very severe and thus the animal should be put to death. Rav Sheshes answered that the Torah commands that trees used for idol worship be destroyed due to the sin which was committed with them. This law implies that an animal which participated in a serious sin should be killed even when the person involved does not suffer embarrassment as a result of his sin. Abaye comments that "this one's Kalon is great, and this one's Kalon is a little."
What is Abaye saying?
(a) RASHI (DH Amar Abaye and DH v'Zeh Kelono) explains that Abaye argues with Rav Sheshes, who says that the fact that the sin is serious is enough to warrant the death of the animal. Abaye says that only the animal of a Jew is put to death because, besides the seriousness of the sin, the Jew experiences great embarrassment as a result of his deviant behavior. A Nochri's animal is not put to death, because the Nochri is only slightly embarrassed from his act.
(b) In an alternative explanation, Rashi suggests that Abaye agrees with Rav Sheshes' ruling that the animal with which the Nochri sinned is killed. However, he does not agree that this is derived from the law that requires that trees of Avodah Zarah be destroyed. The CHIDUSHEI HA'RAN explains that Rashi means that one cannot derive from the Torah's requirement that trees be destroyed so that they not serve as a reminder of a sin that animals should be killed as well for this reason.
(c) The CHIDUSHEI HA'RAN gives a different explanation for Abaye's words. Abaye is in complete agreement with Rav Sheshes, and he is defending Rav Sheshes' inference from the law concerning trees. Although the Torah requires that trees of Avodah Zarah be destroyed because a serious sin was committed with them, perhaps an animal is not killed because it is a higher form of life than a tree. For this reason, one cannot learn from the law of trees of Avodah Zarah that an animal should be killed. On the other hand, the Torah teaches that an animal is killed when a very embarrassing sin was committed (i.e. when a Jew had relations with it). Accordingly, the law of an animal with whom a Nochri sinned can be derived from the law of trees of Avodah Zarah. Just as trees are cut down when a serious sin was committed with them, an animal is put to death when a seriously embarrassing sin is committed with it. This is what Abaye means when he says "this one's Kalon is great" -- that is, one who sinned with an animal, and even a Nochri, "and this one's Kalon is a little" -- that is, the sin committed with trees of Avodah Zarah. Abaye is explaining why Rav Sheshes is able to derive the law of an animal from the law of trees, despite the obvious difference between an animal and a tree. (See TOSFOS, DH Zeh Kelono Merubah, who has an entirely different explanation of the Gemara). (Y. MONTROSE)
2) WHAT NAME MUST THE "MEGADEF" USE IN ORDER TO BE LIABLE?
OPINIONS: The Mishnah states that a Megadef is not liable unless he explicitly says the name of Hash-m in his curse. The Gemara (56a) explains that a Megadef is not one who curses Hash-m, but one who curses Hash-m with Hash-m's own name. What exactly is the name of Hash-m to which the Gemara refers? Does any one of the names of Hash-m qualify, or are there specific names of Hash-m which must be said in order for a person to be considered a Megadef?
(a) The RAMBAM (Hilchos Avodah Zarah 2:7) writes that a Megadef is liable for Sekilah only when he says Hash-m's name of "Adnus," spelled Alef, Dalet, Nun, Yud, and then curses that name with any other name of Hash-m which is not allowed to be erased. If he does not use the name of "Adnus" but instead uses a Kinuy (a descriptive appellation of Hash-m), he is not liable for Sekilah (although he does transgress a Lo Ta'aseh).
(b) The Rambam quotes another opinion, with which he argues, which maintains that a person is liable for Sekilah only if he curses the name of "Havayah," spelled Yud, Heh, Vav, and Heh. This opinion is also stated by the RAMAH (in IGROS HA'RAMAH; see there at length).
The Ramah asks why the Rambam differentiates between the name being cursed and the name used to curse. The Mishnah (56a) represents the case as "Yakeh Yosi Es Yosi" -- "Yosi should hit Yosi." This implies that the criteria are the same for both names. This is also evident from the Gemara later which says that one is liable only when he uses the name of Hash-m that contains four letters. The Gemara asks that this statement is unnecessary, since the Mishnah already provides the example of "Yakeh Yosi Es Yosi." It is clear that the Gemara understands the name "Yosi" not just as an example, but as a hint to the name that must be used by the Megadef. This cannot be true, though, if one "Yosi" means one name of Hash-m, while the second "Yosi" means another name. This question is also asked by the LECHEM MISHNEH.
The CHAZON ISH (Sanhedrin 20:2) answers that the Rambam understands that only the second "Yosi" refers to a four-letter name of Hash-m. The first "Yosi" is stated only because the second word "Yosi" is used as a hint to the four-letter name of Hash-m which is being cursed. Once the Mishnah uses "Yosi" at the end of the statement, it uses it at the beginning as well. (Y. MONTROSE)