1) THE DEFINITION OF A "DAVAR SHE'EINO MISKAVEN"
QUESTION: The Gemara (116b) cites the Tosefta which states that when the fourteenth of Nisan occurs on Shabbos, one may skin the animal, on Shabbos, that he will use as his Korban Pesach in order to remove the intestines, which are offered on the Mizbe'ach. The Gemara asks that such an act should be forbidden because of the Melachah d'Oraisa of skinning an animal. The Gemara answers that when one skins the animal in order to remove the intestines, he does not have intention to obtain the hide of the animal, but rather to remove the intestines, and thus his act is a "Davar she'Eino Miskaven." The Gemara asks that his act is nevertheless a "Pesik Reshei" that the hide will be removed. The Gemara answers that he tears off the hide in small pieces, and thus his act is not considered an act of skinning at all.
REBBI AKIVA EIGER questions the basic premise of the Gemara. Why is this act of skinning, even if it is done only to remove the intestines, considered a Davar she'Eino Miskaven? A Davar she'Eino Miskaven is when one intends to do one act, and incidentally he performs another act. Typical situations of Davar she'Eino Miskaven include one who intends to sweep dirt off the floor (the intended act: sweeping away dirt) and he unintentionally smoothes the floor (the resultant act: smoothing the ground), or one who drags a bed across the ground (the intended act: dragging) and he unintentionally digs a furrow in the floor (the resultant act: digging). In such cases, the person does one act, but another act occurs simultaneously. If the second act will inevitably occur, then the act is a Davar she'Eino Miskaven with a Pesik Reshei.
In the case of the Gemara here, though, the person is not doing one act with a secondary result of another act (skinning) being done. Rather, he intends to do the act of skinning the animal. He merely does not intend to do it for the purpose of obtaining the skin. It is not a Davar she'Eino Miskaven, because he has full intention to do this act (skinning) and no other act. Rather, it is a Melachah she'Einah Tzerichah l'Gufah, since he is doing it for an unusual purpose. (This case is comparable to one who digs a ditch in order to obtain the dirt, and not in order to make a ditch, or to one who captures a snake in order to protect oneself from harm, and not in order to obtain the body of the snake, or to one who extinguishes a fire in order to put out the light, and not in order to produce charcoal.) This type of act is forbidden according to everyone, even Rebbi Shimon (mid'Rabanan), and it is unrelated to the concepts of Davar she'Eino Miskaven and Pesik Reishei!
Why, then, does the Gemara refer to skinning the animal as a Davar she'Eino Miskaven?
ANSWER: Perhaps we may understand the Gemara based on the words of RABEINU CHANANEL. According to Rabeinu Chananel, skinning the Korban Pesach is considered a Davar she'Eino Miskaven because the person "does not have intention to skin the hide, but rather to expose the flesh (and the underlying intestines) of the animal" in order to remove the intestines. A Davar she'Eino Miskaven, as mentioned above, is when an unintended action occurs. For example, when one digs a ditch in order to obtain the dirt, he does only one action -- the removal of dirt from a certain area. Through that single action, (digging) on the single object (dirt), two things are accomplished: he gets the dirt, and he makes a ditch. That is a Melachah she'Einah Tzerichah l'Gufah.
In the case of the Gemara here as well two actions are being done simultaneously. The person removes the intestines from the animal (see RASHI, 116b, DH Ad ha'Chazeh). His action is defined as one which makes the intestines underneath the flesh accessible. A second action which simultaneously occurs on another object without his intent is that the skin is removed. Therefore, skinning the Pesach does indeed fall under the category of Davar she'Eino Miskaven.
(Rebbi Akiva Eiger apparently maintains that exposing the flesh is not an appropriate description of the action; the action of exposing the flesh may indeed be described as skinning.)
2) CUTTING THE CHALAH ON SHABBOS
OPINIONS: The Gemara says that when one cuts the Chalah at the Shabbos meal, he should lift both loaves of Lechem Mishneh while he recites the blessing of "ha'Motzi." Rav Kahana rules that he should then cut one of the loaves. The Gemara relates that Rebbi Zeira would cut "his entire meal" from the Chalah. What does this mean?
(a) RASHI explains that Rebbi Zeira would cut a very large slice of bread which would last for the entire meal. He did this in order to show how beloved the Shabbos meal -- and thus Shabbos itself -- was to him.
(b) The RASHBA disagrees with Rashi. He argues that Rashi's explanation of Rebbi Zeira's custom to cut a large slice has nothing to do with the subject matter of the Gemara here, which discusses the preparation of two loaves for Lechem Mishneh. Rather, the Rashba explains that the Gemara means that Rebbi Zeira cut through both of his two loaves of Lechem Mishneh.
HALACHAH: The SHULCHAN ARUCH (OC 274:1) cites Rashi's opinion (a) as the Halachah and says that one should cut one of the two loaves, and he should cut a large slice.
The VILNA GA'ON (in BI'UR HA'GRA there) rules in accordance with the Rashba's opinion (b), that one should cut both loaves of Lechem Mishneh, like Rebbi Zeira did.
Elsewhere, the Vilna Ga'on points out that this ruling resolves a puzzling statement of the Zohar. The Zohar says that a person should have twelve loaves of Chalah on Shabbos, to correspond to the twelve loaves of the Lechem ha'Panim in the Beis ha'Mikdash that were eaten on Shabbos. If we eat Lechem Mishneh for three meals, we have only six loaves. How do we have twelve?
1. One custom (common among Chasidic Rebbes) is to recite ha'Motzi on twelve loaves (or small Chalah-rolls) at each meal.
2. Another custom is to have four loaves (instead of two) at each meal, so that the total number of loaves at all three Shabbos meals is twelve.
3. The Vilna Ga'on explains that it suffices to have only two loaves at each meal. However, since one is supposed to cut through both loaves, one obtains four halves of loaves at each meal, or twelve half-loaves over the course of Shabbos! (See Berachos 4b, where a "half" is also called one whole entity.)