1) THE ARGUMENT BETWEEN REBBI ELIEZER AND REBBI AKIVA
QUESTION: Rav Hamnuna offers a second explanation for the argument between Rebbi Eliezer and Rebbi Akiva in the Mishnah. He says that the Mishnah is discussing pieces of cloth smaller than three by three Tefachim but larger than three by three Etzba'os. The argument between Rebbi Eliezer and Rebbi Akiva revolves around the dispute between Rebbi Eliezer and Rebbi Yehoshua in Kelim (28:2) with regard to "Kulei Matlaniyos."
Why does the Mishnah here in Shabbos discuss a topic which seems entirely unrelated to the laws of Shabbos and belongs in the Mishnayos of Kelim?
(a) RASHI explains that the garment under discussion in the Mishnah here is a small piece that is hanging on a hook behind the door, which the owner decided to use as a plug for the bath drain. It could be that it was common to use such scraps for wicks as well, and therefore the Mishnah discusses using such a piece of cloth as a wick. The Mishnah records the argument concerning whether or not the wick needs to be singed before it is lit, because that argument deals with the same type and size of object (the wick) which the argument concerning Tum'ah discusses. Indeed, the Mishnah could have discussed only the argument about singeing a wick, but it cited the argument concerning Tum'ah because the two topics deal with the same object. (According to Rashi, the discussion of Tum'ah indeed is unrelated, Halachically, to the discussion of pre-lighting a wick.)
(b) The RITVA explains that the garment or scrap that the Mishnah is discussing is not hanging on a hook, but it used to be hanging on a hook. The owner now has designated it as a wick. Such a designation makes it lose the status of a usable garment, the same way that designating it as a plug for a drain does. The Tana'im are arguing whether the act of taking the cloth and using it as a plug, or folding it into a wick, removes its status as a usable garment.
Accordingly, the explanation of the argument in the Mishnah is basically the same as the Gemara earlier explained (28b) -- the Tana'im are arguing whether or not Kipul (folding a scrap into the shape of a wick) removes the scrap's status as a "usable garment." The difference between whether they argue in the case of Kulei Matlaniyos or in the case of Kipul Mo'il is basically whether the argument in the Mishnah involves a cloth less than three by three Tefachim (Kulei Matlaniyos) or whether it involves a cloth of any size that is folded up (or perhaps a cloth that is exactly three by three Etzba'os; see Rambam).
According to the Ritva, the reason why the Mishnah records this argument is because the question of Tum'ah specifically involves something that is presently being used as a wick.
2) DERIVING PLEASURE FROM "SHA'ATNEZ"
QUESTION: The Gemara cites the Mishnah in Kil'ayim that states that a garment seller is permitted to wear a garment of Kil'ayim as long as he does not intend to derive pleasure from it, according to Rebbi Shimon (who maintains that if one does not have intention to transgress a prohibition, his action is not considered a transgression).
However, Rebbi Shimon agrees that if the transgression will definitely occur as a result of one's action, then it is forbidden even if he does not intend for it to occur ("Pesik Reishei"). Here, the person wearing the garment definitely derives pleasure from it, since he is wearing it in the rain and it protects him! Why is he permitted to wear the garment?
(a) TOSFOS (u'Vilvad) answers that the garment seller is permitted to wear the Kil'ayim on top of other clothes. When worn on top of other clothes, it is not certain that he will derive pleasure from the forbidden garment.
(b) The RITVA explains that the seller does not actually wear the garment. He merely places it over his shoulders, and the rain may wet him despite the garment slung over his shoulders.
The RAMBAM (Hilchos Kil'ayim 10:16) also says that the seller may place it over his shoulders, but for a different reason. The Rambam maintains that wearing a garment of Kil'ayim ("Levishah") is forbidden even when one derives no pleasure from it. Only when he does not wear it in the normal manner ("Ha'ala'ah") -- for example, he throws it over his shoulders -- does the prohibition depend on whether he derives pleasure from it. (HAGAON RAV CHAIM KANIEVSKY in DERECH EMUNAH, p. 75)
(c) The RAN in Chulin (32a of the pages of the Rif) says that the prohibition of "Pesik Reishei" (doing an act that will definitely result in a second outcome, aside from the intended outcome, which transgresses a prohibition) applies only to prohibitions that depend on an action being done. Here, though, the prohibition is one of enjoyment and involves no real action. Since enjoyment depends entirely on a person's frame of mind, "Pesik Reishei" does not apply. A person cannot enjoy something against his will. (The Ran cites a proof for this. The Gemara teaches that "ha'Mis'asek b'Chalavim v'Arayos Chayav" -- one who unintentionally eats forbidden Chelev or unintentionally participates in forbidden relations is Chayav. Only in those two cases is one Chayav for deriving pleasure without intention to do so, because there the source of the pleasure physically enters the person's body, and thus the pleasure does not depend on his frame of mind. In all other cases of forbidden pleasure, though, one must intend to derive pleasure in order to be Chayav.)