Bechoros 46a - Who is the halachic mother?

The issue of surrogacy and determining whether parenthood depends on genetics or on birth is very complicated in halacha and difficult to prove. See here for an article by Rav Zalman Nechemia Goldberg Shlit"a where he proves from various sources that the mother who gave birth to a child is considered the mother in halacha, not the mother who donated the genetic material. This is not the forum to weigh in on such a major topic but one of the cases in our mishna opens it up for discussion. 

Regarding fatherhood, it would seem that it is determined by the one who contributed the semen, since that is the only active role the father takes in producing the child. However, we find that if a man would have relations with a non-jew, the child born would not be halachically related to the father. Rashi writes that if a woman converts while pregnant, the child wouldn't inherit from the biological father since conception happened with a mother who was a goy, the Torah no longer connects the semen to the father - דזרע מצרי רחמנא אפרקריה דכתיב וזרמת סוסים זרמתם. Tosafos agrees, but comments that if the mother converts while pregnant, the child anyway isn't related to the father because the child is considered a convert and גר שנתגייר כקטן שנולד דמי breaks his relationship with his biological family. Therefore, it would seem that in a situation where the bio mother and the surrogate mother are both jewish, we would consider the father to be the father. But, if either one is not Jewish, whether the father is considered the father would seem to depend on who is the mother. If the bio mother is considered the mother, perhaps we would consider the bio father the father even though his semen eventually was placed in the uterus of a non-jewish woman. But, if we consider the surrogate mother to be the mother, the biological fathers connection would likely be broken as well.

It seems that the answer to who is the mother may also lie in this case. When a woman converts while pregnant, we consider the child born after conversion to be a bechor regarding pidyon ha'ben - he is the פטר רחם. It would seem that before we entertain the ability of the child to be considered the פטר רחם of this woman, we must first consider him the child of this woman. The gemara says in Yevamos 78a that when a woman converts while pregnant, the conversion works for the child also and he is considered a convert (the womb isn't a chatzitza for the tevilla). Since we would apply כקטן שנולד דמי at the time of conversion, we would not consider the woman pregnant with her own child (even if conception would normally determine motherhood), yet when the child is born we consider him to be a פטר רחם. It would seem that birth determines the relationship between the mother and child because otherwise we shouldn't consider this child to be the פטר רחם. One can disagree with this logic by underlying the assumption. Perhaps motherhood is not a prerequisite for this child to be a פטר רחם. Therefore, even though we wouldn't consider him to be the child of this mother, he would still have kedushas bechor for pidyon ha'ben.

R. Zalman Nechemia cites an excellent proof that it is dependent on birth from the gemara in Yevamos 97b that says when a woman converts while pregnant with twins, the two brothers are considered brothers for the prohibition of אשת אח (if one would have relations with the others wife after he dies). Even though conception would not consider them brothers because they went through a conversion in the process, the halacha still considers them to be brothers because they are born from the same womb. Just as the relationship between the two brothers is determined at birth, the relationship to the mother should also be determined at birth. According to this approach it is not gestation or incubation of the surrogate mother that would determine her to be the mother in halacha, because the gemara indicates that the same halacha would be true if the mother converted well into her ninth month, a day prior to the birth of the child. Rather, it is the actual birth that would determine the familial relationships.

Rav Zalman Nechemia points out that the gemara in Chulin 70a would seem to imply the exact opposite. The gemara discusses a case where an animal gives birth to a bechor directly into the uterus of another, the second animal then gives birth to this bechor and the gemara wants to know whether a child that doesn't belong to it can exempt it from bechor (in the future). The implication of the gemara is that the child doesn't belong to the second mother, even though it also gave birth to it. However, Rav Zalman Nechemia rejects this proof. He points out that since the first animal also gave birth to it, the child already has a mother, therefore the second mother isn't considered a mother. But if the surrogate mother is the first to give birth to the child (as a viable human being or animal), the surrogate mother would be considered the mother.
According to Rav Zalman Nechemia Goldberg the proof from Yevamos 97b is sufficient evidence that the family relationship is established at birth, therefore the surrogate mother is considered the mother. It would therefore follow that if he surrogate mother were a non-jew, even if the genetic mother was jewish, the child would not be jewish.
However, my uncle, Rav Shabtai Rappaport has a very unique (and complex) approach to this issue that I found in an article online - see here. He considers the gemara in Yevamos 97 evidence for determining the family relationships in regard to עריות but not for the purpose of determining status as a Jew. He suggests that the fact that the gemara in Yevamos 78 considers the child of a pregnant convert to be going through his own conversion, implies that the child's religious affiliation is determined at conception by the genetic mother. Since the genetic mother is a non-jew at the time of conception, the child would not be a Jew unless we consider him to have undergone his own conversion. Even if the mother converts while pregnant and the child is born to a Jewish mother, this would not transform him into a Jew since his genetic material wasn't Jewish at the moment of conception. In the case of surrogacy it would then follow that the surrogate mother is considered the mother, but the genetic mother determines whether the child is a Jew. When the surrogate mother is a non-jew and the genetic mother is a Jew, the child will be Jewish but his "mother" will be the non-jewish woman.
The approach of Rav Shabbtai Rappaport is novel, but it is odd to separate between the question of who is the mother and the one who passes on the Jewish "gene". To me it seems that the proof from the pregnant mother converting doesn't force us to say that Jewishness is passed on by the genetic mother. Perhaps if the mother were able to convert without also converting the fetus she is carrying, the child would still become Jewish upon birth from a Jewish mother. But, since the conversion of the mother automatically works on the child that she is carrying, the child is considered Jewish due to conversion rather than a result of being born to a Jewish mother.

Bechoros 45b - Kohein Marrying a Gerusha

The Mishna says that a kohein who marries a woman who is forbidden to him must make a neder to make her off limits in order to be kasher to do avoda. The gemara says that even if he hasn't actually divorced her, he can make the neder to continue doing the avoda and divorce her when he is done with the avoda. The gemara explains that we insist on a neder rather than just a formal acceptance that she should be off-limits to him (which is what we require for a kohein who is me'tamei l'meisim) because there more of a yetzer ho'rah for women who are forbidden to him.

The Shulchan Aruch (128:40) writes that a kohein who is married to a divorcee is not allowed to do birchas kohanim, nor is he entitled to any privileges of a kohein such as reading first in the torah. Even if he actually divorces her, he isn't entitled to these privileges until he makes a neder על דעת רבים which cannot be overturned that he will not marry women who are forbidden to him. Although the gemara seems to allow him to continue to do avoda after making the neder, even before divorcing her, we demand both that he divorce her and that he make the neder. The Be'er Hei'tev explains that the gemara only allows him to temporarily complete the avoda because he will divorce her immediately when he is done, but he is not allowed to simply make a neder and continue to stay married to her (he must divorce her at the first opportunity).

The M.B. explains that this penalty applies only to aveiros that are specific to kohanim, not to aveiros that apply to regular Jews as well (such as chilul shabbos). The M.B. quotes the Rambam who explains that when a kohein is lax in one mitzvah we don't add to his laxity in mitzvos by forcing him to forfeit the mitzvah of birchas kohanim. The concern of a rasha giving a bracha to klal yisroel he downplays because the bracha is really from Hashem, not from the Kohein.

The situation recently arose about a kohein who has been living with a non-jewish woman for many years and was recently told that he can no longer du'chan. What is the status of a Kohein who is living with a non-jewish woman? Does this qualify as a violation of something that we penalize him for by removing his privileges to du'chan and get the first aliya, or is this considered to a be a violation of other aveiros that doesn't ruin his rights as a kohein (which the mishna berura says includes even arayos)? Would we consider being married to a gerusha worse in this sense than being "married" to a non-jewish woman? To me it would seem very strange that a kohein who is "married" to a non-jewish woman would be kasher to duchan but if she would convert (making the issur slightly less severe), he would be passul. It is possible that although we don't remove privileges of a kohein who violates arayos or other aveiros, that is because each aveira is separate and in between he is not in a state of doing aveira. But, when he is "married" to a goy, since he is in a constant state of "being married" (meaning living b'kvius with her), it is not better than being married to a divorcee and we don't let him du'chan. A similar distinction is made by the Biur Halacha who discusses a kohein who is me'tamei l'meisim. The language of the Shulchan Aruch implies that even if he only does it once he becomes passul, but the language of the Mishna implies that only if he does it regularly does he become passul. The Biur Halacha asks, why when he marries women even one divorcee would he become passul, he only did it once? To this he answers - כיון דהוא מחזיקה לאשה ועומד במרדו הלא הוא מועד לאיסור זה. Meaning, a kohein who marries a gerusha is in constant violation of the prohibition, and the same may be said when he "marries" a goy. It seems to me that although there is to תפיסת קדושין to a goy, the penalty should still apply. Just as those opinions who hold that there is no tefisas kiddushin between a kohein and a gerusha would certainly agree to the Mishna that we penalize a kohein from "marrying" a gerusha, the same can be said for a goy. Even though there is no technical tefisas kiddushin, the k'vius of being legally married or living together permanently could be similar to marriage to a divorcee.
I just found that the Aruch La'ner addresses this question in his teshuvos Binyan Tziyon (6).  SEE HERE. He seems to assume that a goy is considered a p'sul kehuna because the Rambam writes that a kohein who has relations with a goy receives lashes for relations with a "zona". The Rambam clearly considers a goy to be from the p'sulei kehuna. Yet, he leans toward being ma'tir since the issur here seems to only be a penalty d'rabonon and we only find it in a situation where he is actually married. However, he isn't willing to be matir l'ma'aseh unless another posek would agree with him.

Bechoros 38b - Is a Mum that can be cured considered a mum ka'vuah?

It is clear that when a bechor has a mum that will heal by itself, it qualifies as a temporary mum. Although it cannot be sacrificed as a korban until the mum heals, it would not constitute a mum to permit the shechting of the bechor as the gemara said on 37b. Tosafos discusses a mum that will not heal on it's own, but is curable through medical intervention. According to the first approach of Tosafos any mum that is curable, even if it will take medicines or surgeries, would qualify as a temporary mum thereby retain full kedusha of bechor. According to the second approach of Tosafos, a mum that requires some form of medical intervention to heal it, would qualify as a permanent mum and the bechor my be shechted and eaten without the medical intervention. 

This second approach of Tosafos opens up a very peculiar status. One can have a bechor with a mum that is curable but will not heal on it's own and is permitted to shecht it since it doesn't retain the kedusha of bechor. But if he decides to offer the medical treatment to cure the mum, the kedushas bechor will return. The Maharit Algazi questions whether this it is possible for the kedusha of a bechor to be restored through the healing of it's mum. It is very different than a temporary mum where the bechor retains it's full kedusha status even while it has a mum, just that it can't be brought as a korban. Here the kedusha status actually disappears when it gets the mum that will not heal on it's own, therefore you can shecht the animal and eat it, but if you fix the mum the original kedusha status will return. 

The Maharit Algazi cites a very interesting source for this phenomenon. The gemara says in Yoma 64a learns from a pasuk that after a temporary mum heals the animal can be brought as a korban. Why would we need a source for this, can't we simply learn from bechor that after the temporary mum passes the animal becomes fit for a korban? It must be that the pasuk comes to teach us that even when the mum is a mum that won't heal on it's own so that it qualified as a permanent mum and the animal lost it's kedusha status, after the mum is healed through medications the kedusha will return.

Bechoros 37a - Doing Avoda with Temporary Mum

The gemara says clearly that a temporary mum doesn't qualify as a mum at all to permit the shechting of a bechor outside the mikdash, or for redeeming pesulei hamukdashin.  However, it qualifies as a mum to prevent the animal from being brought as a korban until the mum heals. It isn't clear if a temporary mum would invalidate a kohein from doing the avoda even temporarily.

The Chachamim in the braisa say that a kohein cannot become a nirtzah since it will require the making of a mum and invalidate him from doing avoda. From this the gemara proves that the piercing is done in the cartilage part of the ear, rather than the fatty part, since in the fatty part it wouldn't make a mum. Rashi explains that a hole in the fatty part would heal and therefore not be considered a mum. Rashi implies that since the mum will heal, it isn't considered a mum at all to invalidate the kohein from doing the avoda, even temporarily. The Maharit Algazi points out that the third answer of Tosafos (d.h. ka'an) that a temporary mum would invalidate the kohein temporarily seems to be against Rashi.

Bechoros 31a - Paskening For Yourself

The Braisa says that one is not allowed to pasken on their own Bechor that it has a mum to allow himself to eat it. The gemara explains that we are speaking about a kohein who was given a bechor and qualifies as a יחיד מומחה who can normally pasken by himself, but we don't allow him to pasken on his own animal because we are afraid that he will be mo'reh heter for personal benefit.

Tosafos asks that based on this we should never permit anyone to pasken for themselves on any question of issur v'heter. Furthermore, the gemara in eiruvin says in that a talmid chacham can pasken for himself - how does this fit with our gemara?

The Rash in Negaim (cited by Gilyon HaShas) asks Tosafos question and says that it is dependent on whether it is אתחזק איסורא. When the item has a status of being forbidden and relies on the p'sak of the chacham to permit it, one cannot permit their own. But, when there is no default status of issur, one may pasken on their own. The Binas Adam (sha'ar issur v'heter 2) elaborates about this Rash and explains that when a question of issur v'heter would arise on the kashrus of an animal in the shechita process, that would qualify as a chezkas issur where one cannot pasken on their own. But, when it comes to checking the shechita knife on which there is no chezkas issur, one can check their own. It should follow from this that if the shechita knife would get a p'gam in it causing it to be invalid for shechita, the shochet shouldn't be able to check his own knife. However, the Lechem Chamudos (cited by binas adam) explains that anything which is one's control to fix, he is believed on even if it is אתחזק איסורא. Since the schochet can fix his knife by sharpening and removing the nicks, he is believed to say that it has been fixed.

The Binas Adam adds that we learn from our gemara that in a case which is אתחזק איסורא and not in one's own control to fix, even a talmid chacham isn't believed. This is clear from the case of Bechor where a יחיד מומחה isn't believed to pasken on his own.

Following this approach, the Chochmas Adam (109:6) paskens that although a husband may pasken on the bedika cloth of his wife (and she may pasken on her own), if a question develops about chatzitza while immersing in a mikva, the husband cannot pasken. The rationale for the distinction is that he can only pasken when it is not אתחזק איסורא. Once she is established as a Nida and the question is about her becoming tahora, it is אתחזק איסורא.

Bechoros 30b - Accepting Mitzvos Except for One

The Braisa says that a Goy who accepts Mitzvos with the exception of one mitzvah, is not accepted as a convert. R. Yossi Bar Rav Yehuda adds that even for a detail that is d'rabonon we don't accept him. It is unclear from the gemara whether אין מקבלים אותו means that l'chatchila the Beis Din pushes him off, or that even bidieved would prevent the conversion from being binding. In the Teshuvos Beis Yitzchok (cited by Achiezer 3:26:5) he questions whether this is only lichatchila or even bidieved. The gemara in Shabbos 31 about the story with Hillel and the ger who didn't want to accept the oral torah implies that it is only lichatchila. If acceptance of everything would be essential to the geirus working, Hillel couldn't have converted him today just because he was confident that later on he would truly accept. But if it is only a lichatchila, it would be possible for Hillel to convert him today and wouldn't reject him because he was confident that with time he would fully accept (Even within the approach of Rashi who says that he didn't reject the oral Torah just didn't trust it's divinity, it would still seem impossible for Hillel to accept him today unless it would be binding bidieved regardless).
R. Chaim Ozer (Achiezer) rejects the notion that this requirement is merely lichatchila. The Rambam writes that the acceptance of the mtizvos is integral to the conversion (similarly Tosafos in Yevamos writes that it must be done by day in the presence of a Beis Din), the gemara in Bechoros seems to simply be defining "accepting the mitzvos". Therefore, if one doesn't accept a Torah mitzvah the geirus isn't binding. But R. Chaim Ozer questions that perhaps the rejection of a Rabbinic mitzvah wouldn't invalidate the geirus on a Torah level. R. Moshe Feinstein (E.H. 2:4) concurs with R. Chaim Ozer that the accepting of all the mitzvos is essential and not doing so would undermine the conversion entirely. Just as for the Kohen and Chaver mentioned in the braisa, if they lack commitment to their requirements, their acceptance would be void even bidieved, the conversion of the goy would also be void bidieved.

However, there is a very fundamental dispute between R. Chaim Ozer and Rav Moshe regarding the definition of חוץ מדבר אחד. They were faced with Jews coming to convert who were living with non-jewish women and would be Rabbinically prohibited to stay with them after the conversion. Therefore, the entire conversion was with the assumption that they would be violating the issur of staying together. Another example would be a Kohein who comes to convert his non-jewish wife, and clearly plans on staying with her after the marriage. This would be a conversion with the intent of violating a Torah prohibition.
Rav Chaim Ozer (3:26:4) writes that one who converts with the realization that their desires to violate a mitzvah is too strong and they will be in violation, would not qualify as a חוץ מדבר אחד and the conversion would be binding. The Braisa only intends to exclude one who stipulates that they are converting on the condition that such activity will not be prohibited to them. They are essentially picking and choosing which laws will be part of their Torah. But one who accepts all of them, just that he or she intends to violate some of them, would be a valid convert. R. Chaim Ozer realizes that following this approach one can potentially "accept" all 613, but not keep to any of them - would their conversion be valid!? He qualifies this by saying that if we are sure that he will definitely violate major prohibitions in the Torah such as Shabbos and Kashrus, it is and indication that he doesn't mean to truly accept mitzvos, and the lip service of declaring his acceptance is worthless. It is hard to understand where exactly R. Chaim Ozer would draw the line. Perhaps he would not consider violation of details an invalidation of the conversion, only the uprooting of an entire mitzvah. The underlying approach of R. Chaim Ozer seems to be that one need not commit to fulfill every detail, but they have to accept and recognize that this is a prohibition which they should be keeping. Based on this R. Chaim Ozer permits accepting a convert who is honest about where he stands and says that he will not be strong enough to keep one of the mitzvos in the Torah.

Rav Moshe takes a much clearer and harder line on this issue. Anyone who converts with the understanding that they will not be fulfilling one of the mitzvos in the Torah, even if they theoretically recognize it and accept it's divinity, cannot be a convert and the conversion isn't binding. Acceptance by definition is accepting to keep it. Although a ger may be ignorant and doesn't need much education to convert (the gemara in shabbos discusses a case of a ger who wasn't aware of the issur to worship idolatry), he must accept to follow the mitzvos of the Torah as he is taught them. Rav Moshe is troubled with the gemara in Shabbos where Hillel converted someone who wasn't willing to recognize the oral torah. This seemingly is no worse than חוץ מדבר אחד so how was the geirus binding? He explains Rashi to be saying that the convert wasn't rejecting the oral Torah, rather the convert didn't yet believe that the p'sakim of Hillel and Shamai were part of that divine torah. He hadn't yet come to terms with the sages of the generation being able to convey the divine message but wasn't rejecting any particular law. Even so, Hillel wouldn't have accepted him as a convert unless he was confident that in the future he would recognize that even that the discussions of the Rabbis were part of the oral torah. Rav Moshe understands from Rashi that had this qualified as a חוץ מדבר אחד, the geirus wouldn't be binding even bidieved, but since it was merely a lack of education which misled him to think that the torah discussed by hillel and shamai wasn't part of the oral torah, Hillel's confidence that education  would change his attitude was sufficient to convert him today.
The D'var Avrohom (3:28) wrote a letter to R. Chaim Ozer thanking him for sending him a copy of his sefer and offers some comments on this particular teshuva. He writes to R. Chaim Ozer that after reading his distinction of "accepting the mitzvos" and "keeping" the mitzvos, he laughed - ואני חוכך בזה. In this aspect he concurs with R. Moshe that if one "accepts" something with the intent of violating, it doesn't qualify as an acceptance. But regarding the first issue whether the חוץ מדבר אחד is enough to invalidate the geirus, he questions that it may only be a lichatchila requirement as suggested by the Beis Yitzchok. Strangely enough, Rav Moshe (Y.D. 3:106) in a later teshuva leans toward saying that the חוץ מדבר אחד is only a lichatchila for the beis din to reject him, but is not me'akev the geirus. He bases this on the point that was mentioned by R. Chaim Ozer that the rejection of a d'rabonon couldn't invalidate the geirus on a Torah level, therefore it would just be a lichatchila. Since the same language is used for the rejection of a Torah mitzvah - אין מקבלים אותו, this would also only be lichatchila.

There are some orthodox batei dinim that are lax in their insistence on kabalas ha'mitzvos. According to R. Chaim Ozer this would often not prevent the geirus from being binding, but according to Rav Moshe (in the earlier teshuva) any mitzvah that wasn't fully accepted at the time of the geirus would invalidate the entire process.
Unfortunately, I have seem many converts who reject certain halachos such as hair covering and other tznius related issues very soon after their conversion, and there is reason to believe that they had never intended to adhere to these rules. R. Moshe (y.d. 3:106:1 end of section) writes that when the religious people of that community are lax in certain halachos, it wouldn't be fair to consider these things a חוץ מדבר אחד to invalidate the geirus because the fact that all the "religious" women don't abide by it, causes the convert to think that it is just a chumrah being imposed by the beis din.Therefore, rather than regarding this as a חוץ מדבר אחד where she fails to accept something, it can be regarded as a lack of education which would not invalidate the geirus.

Bechoros 29a - Payment for Mitzvos

The Mishna says that one is not allowed to receive payment for judging, testifying, or doing the mitzvos associated with para aduma, and if one receives payment he is penalized that we invalidate what he did. The gemara explains that this is based on a general principal of מה אני בחנם אף אתם בחנם, which is learned from a pasuk that demands that we model ourselves after G-d and not take payment for the doing of mitzvos such as teaching Torah or paskening on questions. Although there is already a prohibition against a judge taking a bribe, Tosafos explains that this source is necessary to forbid him from taking payment that is not meant to influence the outcome of the judgement (but if it influences the outcome in either direction, it is regarded as a bribe).

When the gemara cites the source for not accepting payment as being the requirement to model G-d and do it for free, Rashi gives the examples of authorizing a p'sak i.e. din, and teaching Torah. Rashi fails to mention the issue of testifying and preparing the para aduma waters. The Cheishek Shlomo suggests that accepting payment to testify according to Rashi is only prohibited m'drabonon, not from the Torah. If it were forbidden m'doraysa it would be tantamount to a witness taking money to testify falsely categorizing him as a רשע דחמס and being passul for all testimonly. The Mishna implies that we only invalidate this testimony, implying that his violation isn't d'oraysa. It also isn't clear from Rashi whether payment for other mitzvos is forbidden m'doraysa or only m'drabonon.

The Rashash cites the Bartneura who elaborates about those who officiate gittin and take payment. He is assuming that sidur ha'get qualifies as din and would invalidate the gett. However, the Rama (E.H. 154) says that it doesn't qualify as din, just as limud ha'torah. The Rashash points out that this would justify the gett being kasher, but wouldn't justify the practice to accept payment for officiating a gett since it would still be a violation of מה אני בחנם אף אתם בחנם as we find by talmud torah. Tosafos justifies those who take payment for studying Torah based on the דייני גזירות in Yerushalayim who relied on this for their livelihood and therefore became the community responsibility to support them so that they can maintain their important work. This logic may also apply to mesadrei gittin or those who do other mitzvos i.e. milah for their livelihood. Someone asked me how I can charge to do a bris - i answered that the mitzvah of bris milah is to cut. I don't charge for the mitzvah of doing a bris, I only  charge for stopping the bleeding.

Bechoros 25a - More about Davar She'eino Miskavein

The gemara suggest that R. Yossi Ben Meshulam agrees with Rav (who paskens like R. Yehuda) that דבר שאינו מתכוין is forbidden. How then does he permit the cutting of the black parts of the hairs of the פרה אדומה leaving behind only the red parts, although he isn't intending to be גוזז but to fix the parah a'duma, it should still be a violation? The gemara implies, and Rashi explains explicitly that since his intent when he is cutting the black parts of the hair is to fix the cow rather than take the hairs, it would be considered a דבר שאינו מתכוין. Tosafos points out that this seems to be a very strange application of דבר שאינו מתכוין. Normally a דבר שאינו מתכוין is where one doesn't even intend to do the ma'aseh issur, but where one intends to do the act of issur just that he is doing it for a different purpose than it is normally done for, it would be considered a מלאכה שאינה צריכה לגופה (which is a special p'tur in hilchos shabbos due to מלאכת מחשבת- it doesn't apply to other areas of halacha and even on shabbos is exempt from punishment but forbidden). In this case where the person is cutting the hairs of the parah a'duma intending to do the act of cutting, it would be similar to a standard מלאכה שא"צ לגופה, but shouldn't qualify as a דבר שאינו מתכוין? Tosafos asks this question in very few words -

 דאין זה כשאר לשון "אין מתכוין" בעלמא דכיון דבכוונה גוזז במספרים. Why does the gemara consider this to be a davar sh'eino miskavein? 

It seems to me that by certain מלאכות the purpose of the act is so integral to the melacha, that when the act is done for a different purpose it is tantamount to not intending to do the act at all. The prohibition of גוזז on kodshim is that it is forbidden to do things that enable one to take the products of the animal (whether it is the wool, the work in the field or the milk), while it is still alive. Although Tosafos (d.h. sa'ar) explains that the issur is a ma'aseh issur of cutting the wool, unlike the issur of the milk which is an issur on the product, the nature of the issur to cut the wool is because normally one would do this act to obtain the product. When one is גוזז but has no interest in the wool, it undermines the act of גוזז to the point where we consider him to not be intending for גוזז at all. Therefore, when he cuts the blackened parts of the hairs for the purpose of fixing the parah aduma, not for the purpose of using the hairs, it is considered as if he isn't intending to do the act of issur.

Bechoros 24b - Davar Sh'eino Miskavein

There is a machlokes between the Teruma HaDeshen and the Magen Avrohom whether we can be matir one to do a פסיק רישא דלא ניחא ליה - an inevitable action where he isn't interested in the issur outcome, when the issur is only d'rabonon. The Terumas HaDeshen permits a פסיק רישא דלא ניחא ליה באיסור דרבנן and the Magen Avrohom forbids it (O.C. 314:5). R. Akiva Eiger proves that the Magen Avrohom is correct from a gemara in Succah.

Normally we pasken like R. Shimon that a דבר שאינו מתכוין is permitted, not like R. Yehuda who forbids it. However, when it is inevitable - פסיק רישא, even R. Shimon admits that it is forbidden as the gemara says 25a. When the gemara speaks about a p'sik reisha it is usually in a context where the person is interested in the issur outcome. But when the person isn't interested in the outcome - פסיק רישא דלא ניחא ליה, Tosafos in Kesubos 6a cites the Aruch who permits it even by an issur d'oraysa. Tosafos disagrees and holds that it is forbidden at least by an issur d'oraysa. The Terumas HaDeshen and Magen Avrohom argue if we can be matir by an issusr d'rabonon.

Tosafos explains in our sugya that even though Rav paskens like R. Yehuda who forbids a דבר שאינו מתכוין, that is when the issur is d'oraysa. But if the issur is d'rabonon (either because it is mekalkel, or because תולש לאו היינו גוזז), it would be permitted. It seems that a דבר שאינו מתכוין  according to R. Yehuda is worse than a  פסיק רישא דלא ניחא ליה according to R. Shimon. The Aruch holds that פסיק רישא דלא ניחא ליה is permitted, so even though we hold like Tosafos that it is forbidden, we see that there is grounds to be matir. It would be logical to assume that if Tosafos holds that even R. Yehuda would permit a דבר שאינו מתכוין when it is only d'rabonon, according to R. Shimon who is always matir דבר שאינו מתכוין, but is machmir for a פסיק רישא דלא ניחא ליה, he would at least be meikel when the entire issur is only d'rabonon. This would seem to support the opinion of the Terumas HaDeshen, against the Magen Avrohom. However, the M.B. writes that l'ma'aseh, most achronim agree with the Magen Avrohom to forbid a פסיק רישא דלא ניחא ליה even when the nature of the issur is only d'rabonon.

Bechoros 23a - Understanding Bitul B'rov

The gemara raises a concept of an item which is batul whether it is viewed as כמאן דאיתיה דמי. The gemara assumes that if we regard an item that is batul as if it doesn't exist then when a tamei item is batul it wouldn't even be me'tamei by carrying, but if we regard it as existing even while it is ba'tul it would be me'tamei through carrying but not through touching. The gemara leans toward the distinction between carrying and touching implying that we view the tu'mah to be in existence even while it is batul. The rationale for the distinction between carrying and touching is that when one touches something they cannot be touching every molecule at once. Therefore, we can only consider him to be touching an item of tu'mah if the majority is ta'mei, otherwise we would consider the entity to be not tamei. However, when it comes to ma'sah, since when something is carried, every molecule in it is carried, the existence of the tu'mah even as a minority would render the carrier tamei.

Tosafos (d.h. 23a) asks that eating an item should be more similar to tu'mas ma'sah than to tu'mas ma'ga. Why do we permit one to eat an issur that has been batul in rov? Since the minority is considered to still be in existence, it should be comparable to ma'sah where the entire item is being carried or eaten and therefore should be eating issur? Tosafos answers that when one eats something, every small amount that is swallowed is batul b'rov and is therefore similar to ma'ga where the touching of multiple times doesn't make it as if were touched at once. Therefore, just as by tu'mas ma'ga we would identify the entity based on the majority ingredient, the same would be for eating. Tosafos assumes that it would be impossible to eat the entire amount all at once. Perhaps it is because the בית הבליעה can only contain a beitza at one time which it 2 kezaysim. For there to be a full kezayis of issur in the בית הבליעה at once of something that has been batul b'rov, there would have to be more than 2 kezaysim in the beis ha'blia at one time, which is impossible. Furthermore, there should be an issur of eating even a chatzi shiur of issur, unlike tu'mah for which there is no contamination if it is less than the amount needed to be metamei.

The Rosh (Gid HaNashe end of 37) asks the very same question as Tosafos except that the Rosh preempts the answer of Tosafos in his question and says that one should have to be careful to eat in a way where every swallow could potentially contain only the heter food and not the issur food so that it would be more similar to ma'ga than ma'sah? The Rosh answers that we cannot compare tu'mah to issur. There are two types of tu'mah, therefore the chiddush of bitul b'rov may apply to one and not the other, such as to ma'gah and not ma'sah. However, regarding eating, if we would consider there to be any issur in what the person was consuming, the Torah wouldn't allow it's consumption. The fact that the Torah allows one to eat issur that has been ba'tul is a gezeiras hakasuv that in the world of issur, we view it כמאן דליתיה דמי, as if it weren't in existence. Therefore, a piece of issur that is batul in two pieces of heter can even be cooked together (on a torah level) and eaten all together as if the issur disappeared.

The approach of the Rosh seems to assume that the concept of tu'mah that has been batul being metamei by carrying to be d'oraysa, whereas Tosasfos concludes that it is likely only m'drabonon.

Bechoros 22a - Shiur for Opening of Uterus

The gemara quotes the Mishna in Ohalos (7,4) which says that the shiur for pesichas ha'kever is עד שיעגילו ראש כפיקה. The gemara explains that it is the size of a פיקה של צמר which is used for the שתי stitch. The context of the mishna is to know at which point the cervix is considered open enough so that the dead fetus inside can no longer be considered טומאה בלועה and will be me'tamei the vessels that are in the same room as her. It is unclear if this is also the shiur for פתיחת הקבר in the context of the statement in nidah - אין פתיחת הקבר בלא דם. The Nodeh B'Yehuda cited by the Pischei Teshuva (Y.D. 194,4) says that even forcing the cervix open from the outside would qualify as an opening of the cervix and we would have to be concerned that some blood was let out of the cervix. R. Moshe (Igros Moshe Y.D. 1, 83) says that although the binas adam and chasam sofer disagree with the nodeh b'yehuda, they only disagree when one would use a finger to open the cervix because they assume that a finger wouldn't reach through the cervix. However, even they would agree with the Nodeh B'yehuda that if a tool or instrument is used to enter the cervix, it could qualify as an opening of the cervix where we would say אין פתיחת הקבר בלא דם. R. Moshe (Igros Moshe Y.D. 1, 89) says that although the Nodeh B'yehuda says that only something with a very small diameter such as a pieces of straw wouldn't be considered an opening of the cervix, implying that if it were slightly larger it would be considered an opening of the cervix rendering her a nidah. R. Moshe disagrees because the only shiur that we find in chazal for the opening of the cervix is the shiur of כפיקה של צמר, which they also term as a פתיחת הקבר, therefore it is logical that this would be the shiur also in the context of אין פתיחת הקבר בלא דם. Although it is difficult to know exactly the size of the פיקה של צמר that is used for the שתי stitch, R. Moshe assumes that it must be smaller than the diameter of a small finger. Being that the Rambam paskens that it is possible to have an opening of the cervix without any bleeding, and it is possible that an externally forced opening wouldn't qualify as a פתיחת הקבר, R. Moshe is confident in being lenient with any instrument where the diameter is less than the size of an average persons pinky finger.

Bechoros 21b - What Can You Assume When Buying an Animal from a Jew?

The gemara has three opinions when one purchases an animal from a Jew and wasn't told whether or not it had already given birth to a Bechor. Rav says that the assumption is that the first born will be a bechor because if the it had already given birth the Jew would have mentioned it to praise his the item he is selling. Shmuel says that it is a safeik since the seller may have assumed that the buyer wanted it to shecht so it wasn't relevant whether or not it had already given birth. R. Yochanan says that the buyer can assume that it is not a bechor because there is an obligation on the seller to notify the buyer if the first born would be a bechor otherwise he would be in violation of lifeni iever (tosafos).

There is a machlokes Rashi, Tosafos and Rabbeinu Gershom within the opinion of Rav as to what the advantage would be in telling the buyer that it had already given birth. Rashi says that it would have more value since the animal born from here on wouldn't have to be given to the kohein. Rabbeinu Gershom says the advantage would be that it is an animal capable of providing offspring. Tosafos (quoting rashi) says that the advantage would be that the animal has proven it is capable of surviving child birth and therefore more valuable. The Maharit Algazi asks although when the seller doesn't say anything we don't have to be concerned that it actually gave birth to a viable child, but why are we not concerned that it miscarried (ti'nuf) which would also exempt the next born from being a bechor? He explains that according to the rationale of Rashi and Rabbeinu Gershom, the logic would apply to ti'nuf as well. According to rashi since ti'nuf exempts from having to give the next born to the kohein, the seller would notify about tinuf as well. According to Rabbeinu Gershom, perhaps even ti'nuf would be an advantage in showing that it is capable of conceiving (although wasn't able to produce a viable offspring). But, according to Tosafos where the advantage is that the animal is capable of surviving childbirth, this wouldn't apply to ti'nuf. According to Tosafos the seller would have no reason to tell the buyer about the ti'nuf so we should be concerned that it was me'taneif and the next born may not be a bechor? Perhaps this is why Tosafos offers an alternate approach.

************************

Tosafos writes that only a Jew would be believed about the advantage of having already survived a childbirth and therefore being more valuable but a goy wouldn't be believed about this. Tosafos proves from here that even if a goy is מסיח לפי תומו, talking without trying to make a halachic statement, he isn't believed since we assume he is lying to make the item seem more valuable. The Maharit Algazi asks that this implies that if the goy was truly מסיח לפי תומו and not trying to make his item seem more valuable he would be believed even for bechor. But, the gemara says in yevamos that a goy is never believed מסיח לפי תומו on an issur d'oraysa, he is only believed when he is מסיח לפי תומו on an issur d'rabonon, but this is an issur d'oraysa? From this the Maharit Algazi concludes that the Rov of most animals having already given birth after reaching the ages listed earlier in the perek, is a valid rov on a d'oraysa level, just m'drabonon not a good rov since it is dependent on an action (gemara 20a). Since m'doraysa we have a rov that the next born is not a bechor, and it is only d'rabonon that we can't rely on the rov, we can believe a goy if he is truly מסיח לפי תומו without any motive to glorify his item.

Bechoros 19b - Following the Majority

The gemara suggests that perhaps the halacha of following rov only applies to רובא דאיתא קמן, a rov that is in front of us such as the majority of the sanhedrin voting on an issue, or 9 kosher stores and one non-kosher. But a רובא דליתיה קמן may not command the same status and we wouldn't follow it. The gemara rejects this from the fact that we follow the majority in assuming that most children will not turn out to be a s'ris or ay'lonis, even though that is dependent on a statistic of רוב קטנים לאו סריסים ורוב קטנות לאו איילונית נינהו, which is a רובא דליתיה קמן. However, why do we consider the rov by ketanim to be a רובא דליתיה קמן - just as we consider the 9 stores to be a רובא דאיתיה קמן, we should consider the rov of ketanim to be רובא דאיתיה קמן since most ketanim that are alive in the world today aren't s'risim or ay'lonis? Rabbeinu Gershom seems to address this question and writes- דלא חזינא רובא דעלמא אי הוי סריסים אי איילונית אי לא ואפ"ה אזלי בתר רובא. Even though we have a statistic telling us something that exists right now, since the numbers aren't obvious and can't be counted in front of us, it would qualify as a רובא דליתיה קמן. Similarly, the fact that most cows aren't treifos is a רובא דליתיה קמן because the statistic will not create a רובא דאיתיה קמן since they cannot be counted in front of us.

On another note, the gemara says that we don't follow a rov that is dependent on an action such as the fact that most animals would be pregnant by a certain age, which is dependent on the action of mating with a male. The rationale for not following this rov, the Ramban (Halachos of Bechoros) writes that a mi'ut which happens by itself is stronger than a rov that is dependent on an action. Rashba in Chulin 9a says that this limitation is only d'rabonon. Meaning, m'doraysa we follow rov even if dependent on an action but the Rabbonon tell us not to. Therefore, the Chazon Ish writes that we can only be machmir to not follow a rov dependent on an action, but we cannot be lenient to do so. The Binas Adam (sha'ar rov v'chazaka) proves that the Rashba is correct that it is only d'rabonon based on Tosafos ד"ה אי בעית אימא who says that R. Meir who is concerned for the mi'ut is only d'rabonon. Since the first answer of Rava that the concern of the mishna that the animal born now is a bechor is only m'drabonon, the answer of Ravina about not relying on rov which is dependent on an action is also only d'rabonon. However, this proof isn't very solid because when there is a chazaka that supports the mi'ut even R. Meir would agree that we are concerned for the mi'ut even m'doraysa and here there is a chazaka that supports the mi'ut (as tosafos explains in d.h. me'chvarta). The issue of whether R. Meir is concerned for a mi'ut only m'drabonon or even m'doraysa (when there is no chazaka), is a dispute between tosafos and mordechai (mentioned in this blog on the first perek of chulin).

Bechoros 9b - Spending Money for Safeik Mitzva

The Mishna says that if one has a safeik whether they have a peter chamor, they must redeem it with a sheep but don't need to give it to the kohein  since the rule for giving is המוציא מחבירו עליו הראיה - the burden of proof is on the collector. The gemara says that this follows the opinion of R. Yehuda who says that a peter chamor is forbidden to derive benefit from, therefore one must redeem it even though it won't be given, but according to R. Shimon who says that it is permitted, there isn't even a mitzvah to redeem it. 

Tosafos raises an interesting question - A peter chamor without redemption requires it's neck to be broken. Since the mitzvah to break it's neck (arifa) is like any mitzvah where we are strict when there is a doubt, even if it weren't assur b'hanah, there should be a requirement to break it's neck. Tosafos answer cryptically and says that just as one doesn't need to give it to the kohein, there is also no requirement to do the arifa out of safeik. It isn't clear what Tosafos means to say - the concept of המוציא מחבירו עליו הראיה exempts the giving to the kohein but doesn't exempt the breaking of it's neck? 

The Maharit Algazi suggests that since we have a concept of המוציא מחבירו עליו הראיה and apply it even to mitzvos that one is obligated to do by the torah such as all safeik of gifts to the kohein, we can similarly apply this concept to any mitzvah where it is questionable if one needs to fulfill it and the fulfilling of it would entail a loss of money. Since the arifa of the peter chamor would be a loss of money, one isn't required to incur the loss for a safeik mitzvah.

This approach is very difficult to accept. It should follow that if one is in doubt whether they are obligated in matzah on pesach or whether they have already fulfilled their mitzvah, they shouldn't be required to incur any expense to fulfill the mitzvah. Had this been true, it should have been mentioned in earlier poskim. Rather, we generally assume that this rule is limited to mitzvos that require giving, but doesn't apply to expenses that need to be incurred to fulfill mitzvos between man and G-d. Therefore, this concept shouldn't apply to the mitzvah of arifa (breaking the donkeys neck).

The Rashash explains that Tosafos doesn't mean to fully equate the mitzvah of breaking the neck with the giving to the kohein, since the concept of המוציא מחבירו עליו הראיה wouldn't apply to the mitzvah of arifa. Rather, Tosafos holds that the arifa is the consequence when one doesn't fulfill the mitzvah to give the sheep to the kohein as redemption of the newborn donkey which is incumbent upon him. When there is no requirement to give a sheep to the kohein, the mitzvah of arifa would also not apply.

Bechoros 6b - Heter to Drink Kosher Milk

The gemara says that the fact that milk of a kosher animal is permitted to drink is a chiddush because one could have argued that it would be included in either the prohibition against blood (דם נעכר ונעשה חלב), or the prohibition against אבר מן החי since it is part of a live animal. The gemara cites three possible pesukim as the source of the fact that milk is kosher (either the pasuk when Dovid brought milk to the troops, or the pasuk that praises the land of Israel for it's milk which indicates that it is permitted to drink, or a pasuk in Yeshaya).

The Shita Mikubetzes asks, why not use the pasuk by Avrohom when he fed the angels butter and milk. Being that Avrohom kept the entire Torah, the fact that he was willing to give milk to the angels indicates that it is permitted to drink? The R"I answers that Avrohom thought that they were bnei noach. Even if milk were forbidden to Jews, it wouldn't be one of the 7 Noachide laws and permissible for them to drink it. The Shita then cites a Yerushalmi (which is not in the Yerushalmi but in the pesikta and quoted by the da'as zekeinim on parshas vayera) that indicates they ate meat and milk (unlike the gemara in baba meztia which implies that didn't actually eat, and also says that it was served one by one i.e. milk before meat) . When it came time to give the Torah and the mal'achim were complaining they wanted to keep it, Hashem said that every child knows that meat and milk can't be eaten together, yet they ate meat and milk when they visited Avrohom. It isn't clear how this midrash connects to the discussion of the Shita Mikubetzes. Perhaps the Shita is trying to prove that Avrohom thought they were bnei noach from the fact that he fed them meat and milk, so there wouldn't be any proof from there about milk being permitted to drink.

The Maharit Algazi asks that according to the rationale that milk would be assur as אבר מן החי, it would surely apply to non-jews as well. The answer of the Shita that Avrohom assumed they were bnei noach doesn't work if the issur on milk would be an offshoot of אבר מן החי? The Chasam Sofer (y.d. 70) answers that the gemara never really suggested that milk would actually be אבר מן החי or בשר מן החי because it is neither an ei'ver or ba'ssar. Rather the gemara was suggesting that it should be LIKE אבר מן החי in the sense that it would be assur (not not for goyim), based on concept of הטמאים - לאסור צירן ורוטבן וקיפה שלהן. Meaning, since אבר מן החי is assur and the animal is assur when it is alive, so anything that comes from it when it is alive should be included in the prohibition of הטמאים. This prohibition would certainly apply to Jews only, therefore Avrohom would have had no problem giving milk to b'nei noach.

Bechoros 5b - Categorizing Animals Based on Features or Genetics

The Mishna discusses a case where a mother cow gives birth to a child that looks like a donkey. The gemara learns from the pasuk of פטר חמור that the child would not have Kedushas Bechor. It is clear from the gemara that we completely exempt it from any kedusha of bechor, but it isn't clear from the gemara which type of kedusha it would have if not for the pasuk excluding it. Meaning, do we regard it as a cow since genetically it is a cow, just that it looks like a donkey, or do we regard it as a donkey since it looks like a donkey?

It would seem that the answer lies in the end of the Mishna which cites a rule that היוצא מן הטמא טמא והיוצא מן הטהור טהור. The mishna seems to indicate that the genetic makeup of an animal determines the species to which it belongs, therefore an animal born from a kosher animal (even if it looks like a donkey) is kosher. Similarly, an animal born from a non-kosher animal (even if it looks like a cow) is not a kosher animal. If genetics determines the category, we would have to say that a cow that gives birth to a donkey would have been treated like a בהמה טהורה and been brought as a korban on the mizbei'ach, if not for the pasuk excluding it.

However, the implication of the mishna which uses a pasuk of פטר חמור to exclude this case, implies that we really need the pasuk to exclude it from the requirement of פטר חמור, not from kedushas mizbei'ach (although the gemara confirms that it would certainly be excluded from kedushas mizbei'ach as well). The Steipler (4) proves from Tosafos that this is true. Tosafos suggests that for a cow that gives birth to a donkey the pasuk of the mishna (פטר חמור) would be necessary to exclude if from the mitzvah of redemption like a donkey, and the pasuk in the gemara would be necessary to exclude the reverse (a donkey giving birth to a cow) from kedushas mizbei'ach. Although Tosafos concludes that either pasuk would exclude it completely, their logical default for not having a pasuk would be that the animal should be treated as it looks, not as the species of it's mother. Meaning, a cow that gives birth to a donkey would have been treated like a donkey to require redemption despite that it's genetic makeup is that of a cow. The Steipler proves from here that the species of any animal is determined by it's appearance, not by it's genetics. Nevertheless, there is a separate rule that if it looks like a kosher animal but is born from a donkey, it cannot be eaten - היוצא מן הטמא טמא, not because it's a donkey, but because it is a non-kosher cow. Similarly, if it looks like a donkey it is a donkey, yet if born from a cow it can be eaten because היוצא מן הטהור טהור. This approach of categorizing a donkey born from a cow as a "kosher donkey" is significant because for purposes other than eating i.e. eiver min ha'chai it would have status of what it looks like, not what it is genetically.

The gemara 6a seems to strongly support the approach of the steipler that the species is determined by it's appearance rather than it's genetics. According to the rule that having similarities to it's mother can make it have kedusha of bechor, the gemara questions whether a donkey that has similarities to it's mother which is a cow, would have kedusha. The gemara's suggestion of why it is too different from the mother and wouldn't have kedusha is - הא טמאה והא טהורה, הא קדושת הגוף והא קדושת דמים. The gemara describes it as a non-kosher animal and as the value having kedusha rather than inherent kedusha. Clearly, the gemara is understanding that since it looks like a donkey, if it were to have kedusha (because it has similarities to the mother), it would have קדושת דמים like any donkey, not קדושת הגוף like it's mother.

Bechoros 3b - Avoiding Kedushas Bechor

The gemara discusses exactly how much of an animal must be given over to a goy in order to avoid kedushas bechor. The predominant opinion seems to be like R. Huna that the ear is enough, since we find that Rami Bar Rachel did that as well. Tosafos entertains the possibility that we would pasken that one would have to give over to the goy a portion in the animal that if missing would render the animal a neveila or treifa (rav chisda and rava), but considers it to be a chumra. Regarding the fact that one is removing kedusha from animal entirely by selling a portion to a goy, Tosafos suggests that it would only be an issue if one were to sell a portion of the fetus which itself would have otherwise had kedusha, but would not be an issue when selling a portion of the mother. Even though this may not be ideal, Tosafos considers it the proper thing to do nowadays since there is no better alternative and if this isn't done someone will surely violate a more severe prohibition with the animal.

The Turei Even (Rosh HaShana 13) suggests that being mafkir the animal would NOT be sufficient to remove the kedusha of bechor from the fact that Rami Bar Rachel who was looking for the simplest option, didn't use the method of hefker. The Chasam Sofer (Y.D. 316) dismisses the proof since it could be that a proper hefker in the presence of others could have been more complicated and difficult than simply selling the ear to a goy. The Maharit Algazi suggests a complicated approach. Hefker wouldn't work to remove the obligation of bechor on an animal that already has kedushas bechor. However, if one were to be mafkir the fetus prior to it's birth, since at the time when it would be fit to receive kedushas bechor it doesn't have an owner, it wouldn't get kedushas bechor. He then backs off based on a gemara in Chulin and says that even if born as hefker, as soon as a Jew would take possession of it, it would assume kedushas bechor.

Chulin 141b - Punishing for Shiluach Hakein

The gemara says that R. Yehuda gave malkus to someone who clipped the wings of a bird and then sent it away on its feet to fulfill the mitzvah of shiluach hakein because he holds that it must be sent away by flying, not by hopping. The Mishneh L'melech (hil. avadim 18) asks how he was able to punish for this mitzvah. We have a rule - כל מצות עשה שמתן שכרה בצדה אין ב"ד של מטה מוזהרין עליו, meaning that Beis Din doesn't punish for any mitzvah that has a reward tagged onto it. How was R. Yehuda able to punish for shiulach hakein which has the reward of long life attached to it? 

The Maharatz Chiyus suggests based on Rashi (?) that the reason that beis din doesn't punish when there is a reward attached is because by writing the reward the torah is hinting that the this is the reward for doing it and not receiving this reward is the punishment for not doing it, to the exclusion of any other punishment. The Maharatz Chiyus explains that this rule works by other mitzvos, but by shiluach hakein the mishna 142a says that the reward needs to be written to teach that there is tremendous reward even for small mitzvos such as this for which there is very little expense. From here we derive that for all mitzvos there is great reward, making it unnecessary to dictate the specific reward if not for the purpose of exempting you from any other punishment. Therefore, shiulach hakein is an exception to the rule since it serves as the source for teaching that there is great reward for even seemingly simple mitzvos, and is not meant to exclude any other punishment.

It seems to me that Rashi himself is coming to answer the question as to how R. Yehuda was able to punish for a mitzvah that the torah writes the מתן שכרה בצדה. Rashi says that the purpose of his "punishment" wasn't punitive, rather it was רידוי בתוכחה שלא ירגיל בזה, ואין לה קצבה אלא עד שיקבל עליו. Meaning, the purpose was not to punish, rather to change the person and motivate him to fulfill the mitzvah. Although Beis Din may not "punish" or "penalize" for mitzvos on which a reward is tagged on, they may still have the ability to encourage and motivate one to fulfill the mitzvah even through force.

Chulin 139b - Searching after mitzvos

The gemara says that one may have thought that they would be required to search after the mitzvah of shi'luach ha'kein and put in effort to find a birds nest on mountains and hilltops, to which the gemara responds that it only applies when you chance upon it. There is a great debate among the achronim regarding the mitzvah of shiluach ha'kein, whether it is an absolute obligation to send away the mother bird even if one has no particular interest in the baby birds, or is it a mitzvah more similar to divorce where if one wants to do something i.e. take the babies, or divorce their wife, the torah prescribes a format that must be followed. The Chacham Tzvi (83) and Chasam Sofer (100) suggest from this gemara that thought to demand searching after the mitzvah on mountain tops, that it is an absolute obligation. Although the gemara concludes that one isn't obligated to go to the extreme of trying to locate a birds nest, the underlying assumption that it is an absolute imperative even if one has no interest in the babies is never rejected.

On a bit of a different note using the same source, the Mekor Chaim (Nesivos on Hil. Pesach Siman 432) which I cited in my sefer Nasiach B'chukecha (195) proves from our gemara that one is required to invest effort into searching after mitzvos from the fact that the gemara required a specific pasuk to exempt the assumption of searching after the mitzvah on hilltops. Therefore, other mitzvos that don't have a pasuk exempting this level of effort, would demand that extreme amount of effort. However, in my edits on my sefer I pointed out that from Rashi we would be able to prove the exact opposite. Rashi writes - 

שנאמר שלח תשלח ב' פעמים, שומע אני לחזור אחר המצוה הזאת עד שתבא לידו. Rashi explains that the default position for having to put tremendous effort into searching after this mitzvah is not a gobal requirement or assumption that would be by all mitzvos. Rashi says that since we have the double language of שלח תשלח I would have understood that this mitzvah would require one to search after it in order to fulfill it, to which the gemara responds that כי יקרא implies the opposite. Therefore, other mitzvos which have no pasuk specifically implying that it demands an extreme level of effort, one would not have to put in tremendous effort to attain the mitzvah.

Chulin 135a - Reishis Ha'Geiz and Matnos Kehuna Nowadays

According to the Mishnayos both the mitzvah of ראשית הגז  and the mitzvah of מתנות כהונה apply without a Beis HaMikdash and even outside of Eretz Yisroel. However, Rav Nachman 136b made a statement that the minhag is to follow רב אלעאי by ראשית הגז and that it should only apply in E.Y. Rashi comments - והוא הדין במתנות, meaning that there is no rationale to differentiate between ראשית הגז  and the matanos of זרוע לחיים וקיבה. Since the minhag has become to follow רב אלעאי by ראשית הגז, we also follow him for matanos kehuna that they don't apply outside of E.Y. The Shulchan Aruch both in the halachos of Matanos Kehuna (y.d. 61:21) writes that they apply even outside of E.Y. and then cites a יש מי שאומר שאינן נוהגות בחוצה לארץ. The Shulchan Aruch in the context of matanos kehuna writes וכן נהגו on the lenient opinion even though the main opinion seems to obligate matanos even outside of E.Y. Interestingly, the Shulchan Aruch in the context of reishis ha'geiz doesn't even quotes the stricter opinion - he writes that it only applies in E.Y. to which the Rama adds that some says it applies even on a Torah level in chutz la'aretz but we aren't noheig to be machmir. The Shulchan Aruch is more confident about exempting from reishis ha'geiz in chutz la'aretz since that is explicit in Rav Nachman's statement. Although there is no rationale to differentiate between reishis ha'geiz and matanos, the gr"a (61:20) explains that the leniency is based on a minhag which may have only been to be lenient about reishis ha'geiz and not about matanos kehuna. The Beis Hillel (333) struggles with trying to understand why we are even lenient in E.Y. nowadays. Although the Pischei Teshuva (61:8) cites the chasam sofer who would routinely shecht an animal before yom tov and fulfill the mitzvah of matanos kehuna and reishis ha'geiz, the minhag is not to be makpid about fulfilling these mitzvos. The Beis Ephraim (on shulchan aruch 61) quotes the kerisi u'pleisi who wonders why we don't find people going out of their way to fulfill this mitzvah. He quotes the Pri Chadash who argues on the Beis Hillel's (who wrote that he was told that even in E.Y. people don't fulfill the mitzvah of matanos kehuna), and says that they didn't realize what they saw because it is מעשים בכל יום that matnos kehuna are given in E.Y. from the animals that are being shechted. The Beis Ephraim also quotes that the kreisi writes that his son in law insisted on giving matanos kehuna at the pidyon ha'ben of his son. Since he was being machzik the kohein as a kohein for the purpose of discharging his pidyon ha'ben obligation, he certainly can rely on his yichus to give him matnos kehuna.

Chulin 122b - How far do you have to go?

The gemara says that for tefilah and netilas yadayim one must travel 4 mil forward, and just under one mil backward. Rashi explains that we are talking about someone who is on the road travelling and he wants to stop for the day, but knows that he will have a shul 4 mil ahead to daven (Tosafos assumes that this means a minyan, not a physical structure), he must continue to go to the shul. Similarly, if one was hungry and wanted to eat bread but didn't have water to wash his hands, he would be required to wait until he travels 4 mil before he eats.

The Biur Halacha (163) assumes that the shiur of 4 mil is really a time requirement. Since it would take 72 minutes for the average person to travel 4 mil, the gemara is demanding that one wait 72 minutes. A possible scenario would be if one is on an airplane and wants to eat bread but can't leave his seat at the moment, since it is very likely that within 72 minutes he will be able to wash, he is obligated to wait. It isn't clear to me why the Biur Halacha assumes that this would be dependent on time. Rashi uses language of "tircha" implying that one must push themselves to continue to travel, implying that the amount of 4 mil was for a circumstance where he was on foot and walking 4 mil is a significant tircha. Perhaps if he were travelling with minimal tircha he would need to wait longer than 72 minutes.

The M.B. also comments that if one isn't certain that by waiting or continuing to travel they will find the shul or water, they aren't required to wait at all. This is certainly the implication of Rashi who writes in definitive terms that there is water and a shul in front of him.
Another point that the Biur Halacha makes in the name of the Chayei Adam is that if one isn't very hungry he should wait even more than 4 mil. However, Rashi gives an example of one who wants to stop while it is still day and the halacha demands that since it is still day time and easy to travel, he must continue. It would seem that a similar case by eating would be when one wants to eat now but can relatively easily delay. Perhaps if one is very hungry so that delaying is very difficult (on the level of travelling at night), they wouldn't even have to wait 4 mil.

Chulin 121a - Concept of Achshavei

There is a halacha that is recorded twice in Y.D., once at the end of hilchos sheratzim and once in siman 155 in the Rama - מותר לשרוף שרץ או שאר דבר איסור ולאכלו לרפואה אפילו חולה שאין בו סכנה. The obvious implication is that for the sake for refuah it is permissible to eat a prohibited item that has become inedible, but when it is not being done for refuah purposes, it is forbidden. The Yad Avrohom explains based on the Rosh (2nd Perek of Pesachim) that when one burns chometz before pesach rendering it unfit for consumption, it would still be forbidden to eat on Pesach since by eating it he is giving it importance - מדאכליה אחשביה. Based on this it would be forbidden under normal circumstances to eat a bug or other forbidden item that has been burned, but if it is merely being eaten for medicinal purposes it is permitted since the concept of אחשביה only applies when one is consuming it as a food item. This is to the exclusion of the Sha'agas Aryeh (75) who considers the concept of אחשביה to apply even when one is eating something for medicinal purposes. Either way, the concept of אחשביה is a Rabbinic concept. On a Torah level it would seem impossible for one's intent or purpose to determine an item forbidden or permitted.

However, according to R. Yehuda in the mishna, when one gathers the small pieces of meat that are attached to the inner side of the hide together to make a kezayis, it would have status of a kezyais neveila. Rav Huna explains that this is only when he himself gathers them together, indicating through his actions that he is considering it to be important - דאחשביה וגלי דעתיה דלא בטליה מעיקרא: רש"י. Rashi writes that the concept of אחשביה can be used here, not only in the realm of טומאת נבילה, but even in the realm of איסור נבילה. Meaning, his intent to consider the scraps to be meat restores their status even in the world of issur. Tosafos asks on Rashi, where do we ever find that intent could be the determining factor as to whether a food item is permitted or prohibited!? This would seem to be a machlokes between Rashi and Tosafos whether the concept of אחשביה can even work on a d'oraysa level in the realm of issur v'heter.

The gemara on 120a said that חלב -animal fat that had been liquefied should not be included in the prohibition of eating חלב since it would be drinking and not eating, and we need a special source in the Torah to include it. However, the gemara says that blood which the torah forbids as an issur to eat in it's natural state (as a liquid) would also be forbidden if it were congealed - כיון דאקפיה אחשובה אחשביה - since he gave it status through the act of congealing it. This gemara seems to support Rashi, because we are using the concept of אחשביה to maintain the issur of consuming blood even when it is in solid form. But, upon further analysis, we can ask a more basic question. Why does the gemara require this rationale and not simply state that if liquid blood qualifies as eating, then certainly solid blood would qualify? It seems to me that the gemara is bothered by another issue. Since blood is naturally in a liquid state, consuming it in it's solid state could be considered שלא כדרך אכילה - not the normal way of eating. The gemara is saying that since he congeals it for the purpose of eating it as a solid, it is still considered a normal way of eating. We aren't using this rationale to transform the status of the blood from issur to heter, only to say that it still qualifies as a normal way of eating.

Chulin 116b - Keiva as Rennet

The mishna speaks about "keiva" which refers to the enzymes that line the stomach wall of the animal, and the "or ha'keiva" - skin of the keiva, which is the actual piece of the stomach wall. The keiva is considered merely "pirsha" and therefore concludes that even the enzymes that line the stomach of a neveila or treifa animal can be used, but one cannot use as rennet the actual wall of the stomach of a neveila animal.

Rashi discusses milk that is found in the keiva of the animal that is then salted together with the stomach of the animal. Rashi points out that to permit using this milk that was salted with the stomach as rennet, we would have to assume that the milk found in the stomach qualifies as "pirsha" similar to the enzymes. Rashi rejects this notion and considers the milk to be actual milk so that when salted with the meat of the stomach qualifies as meat salted with milk and becomes assur m'drabonon as bassar b'cholov. We would then say that חתיכה נעשה נבילה so that all that milk has status of issur and when used as rennet will spread issur to all the milk since we say min b'mino is not batul (this is rashi's opinion 109a and many other places that we pasken min b'mino isn't batul. tosafos disagrees and holds that we pasken min b'mino is batul - but in this case where it is effective in being ma'amid the cheese, even tosafos would agree that we don't say bitul).

Rashi implies that had we considered the milk inside the stomach to be merely "pirsha", we would be able to compare this case to fish that was placed in a meat dish, which can be eaten with milk using the concept of נ"ט בר נ"ט, meaning a second generational no'sein ta'am. Both the Rashash on Rashi and the Shach (y.d. 87, 31) point out that even if we were to consider the milk that was salted with the stomach lining to be "pirsha" it would still not be comparable to the hot fish on a meat plate that can be eaten with a dairy food. The concept of נ"ט בר נ"ט  only applies when the second generation flavor stand alone as a permitted entity that you are now going to use with milk. However, when the milk is salted with the skin of the stomach, the "pareve" milk inside the stomach absorbs a ta'am rishon of meat. We then take that ta'am rishon and mix it with milk to create cheese. Since the ta'am sheini of meat is immediately mixing with milk, we consider that to be an issur. Rashi writes that he originally thought that the milk in the stomach qualified as pirsha and was matir, implying that he holds that if the milk were truly pareve because it was considered to be "pirsha" then we could compare it to the case of hot fish in a fleishig plate that could be eaten with milk, and doesn't seem concerned with the aforementioned distinction. 

Rashi 111b (d.h. nosein ta'am) writes explicitly that one cannot put hot milk in a fleishig bowl because the second generation flavor of meat is going directly and immediately into the milk. The case here, even if we consider the milk in the stomach to be "pirsha" should be exactly identical to the milk being put in a fleishig plate where Rashi himself holds that it becomes assur!

Chulin 115a - kol she'tavti le'cha

Rav Ashi says that the source for meat and milk being prohibited to eat and benefit from is the pasuk which says לא תאכל כל תועבה from which chazal darshen כל שתעבתי לך הרי הוא בבל תאכל. The gemara suggests that the same problem should apply to food cooked on shabbos, and it should be prohibited to eat and benefit from, but darshens from the pasuk of כי קדש היא לכם that ma'aseh shabbos is permitted. The gemara further tries to suggest that when one violates the prohibition of plowing with an ox and mule together or muzzling while working, the product should be forbidden. The gemara answers that since we permit ma'aseh shabbos, we should certainly permit the products of plowing with an ox and mule, or muzzling it while working. Rashi struggles with an obvious question, why wouldn't we also learn from ma'aseh shabbos that even bassar b'cholov should be permitted to derive benefit from. Rashi explains that there is a difference. When it comes to meat and milk, one is eating the actual issur that the Torah despised, whereas by ma'aseh shabbos and these other aveiros, we are merely speaking about the product of the issur, not the issur itself.

Tosasfos (end of d.h. choreish) struggles with why we consider the food cooked on shabbos to be merely the product of the aveira but not the תועבה itself, whereas by meat and milk we consider the food to be the actual תועבה that was despised by the Torah? Tosafos explains that it must have to do with how apparent the issur is within the item. By meat and milk where the issur is apparent in the product, the product of the aveira is considered the תועבה, but by ma'aseh shabbos where the issur isn't apparent in the product because one cannot tell from the product that it was cooked on shabbos, the food isn't considered the תועבה.

Tosafos approach seems to be using a d'rabbonon style logic to distinguish between bassar b'cholov and ma'aseh shabbos on a Torah level. It would seem difficult to say that appearance of the product would determine whether the Torah renders it a תועבה. The Rashash suggests another distinction to answer Tosafos question. The cooking of meat and milk is that act of prohibition that the Torah forbids, therefore the product of that act is considered a תועבה. But by ma'aseh shabbos the Torah doesn't forbid specifically the cooking of food, rather the Torah forbids any melacha to be done on shabbos. The food that is cooked on shabbos is not a direct product of what is specifically forbidden by the Torah, therefore not considered a תועבה.

I would like to suggest a slightly different approach. According to the approach that meat and milk that have been cooked together are forbidden to eat and benefit from because they are considered a  תועבה due to the fact that an issur was done with them, it should only be forbidden if cooked by a Jewish adult. Had the cooking been done by a child or at least by a goy, where there was no violation in the process of cooking the product shouldn't be considered a תועבה. Yet, Rashi 114b writes that even if cooked by a goy or a child (rashi implies that we don't render an aveira done by a child to be a ma'aseh aveira), we would consider the product a תועבה. Rashi 114b explains that it is not the act of the aveira that renders the product a תועבה, rather the תועבה is the item itself. Rashi understands that it is as if the Torah would have said that meat and milk is a תועבה, therefore stay away from cooking it. When the Torah identifies an item and forbids an action associated with that item, it can be understood that the action doesn't cause the item to be forbidden, rather the torah recognizes the item as something despised herefore forbids the action i.e. cooking. This would only apply when there is a specific item referred to by the Torah such as meat and milk. The Torah considers meat and milk that is cooked together to be a תועבה, therefore forbids any Jew from cooking it. But, even if a goy were to cook it, the item is still a תועבה. In contrast to the issur of ma'aseh shabbos - the Torah doesn't despise the product, therefore forbid the action of cooking. If that were the case then even something cooked by a goy should be included. The fact that it is only considered ma'aseh shabbos when done by a Jew indicates that the action is what is considered forbidden, and the food is merely a product of the forbidden action to cook. This would not give the food a status of תועבה.

Chulin 114a - Is it Forbidden to Benefit from McDonalds?

According to Shmuel there is an extra pasuk to teach that the issur of meat and milk is binding even on top of a preexisting issur of neveila, therefore one who eats neveila cooked in milk would receive lashes. However, the gemara cites an argument between R. Ami and R. Asi limiting the discussion to be whether one who cooks neveila with milk would receive lashes for the act of cooking, but all agree that since the eating is already forbidden due to the issur of neveila, the prohibition to eat meat and milk isn't binding on top of the preexisting prohibition of neveila.

Based on this, the Rambam (machalos assuros 9) paskens that one who cooks neveila with milk would receive lashes for cooking meat and milk, but one who eats it wouldn't receive lashes for eating meat and milk. However, both the gemara and the Rambam (in mishne torah) are silent regarding the prohibition to benefit from meat and milk. Would that be similar to eating and not apply to neveila, or would it be compared to cooking and apply to neveila?

The Dagul M'rvava (y.d. 87) cited by the Pischei Teshuva (6) quotes the Rambam in his commentary to the mishnayos on krisus who suggests that benefit and eating go hand in hand. Since the issur to eat meat and milk isn't binding on top of the prohibition of neveila, the prohibition to benefit is also not binding. The Pischei Teshuva quotes in the name of the kanfei yona who disagrees with the dagul m'ravava, and the Chasam Sofer who says that one who relies on the dagul m'rvava can't be rejected, but in his opinion the kanfei yona is more correct.

The source of the dagul m'rvava is the Rambam in what he refers to as a נקודה נפלאה in his commentary on krisus. The Rambam asks that the issur to eat basar b'chalav should be binding on the issur of neveila since it is an איסור מוסיף by virtue of the fact that meat and milk is forbidden even to derive benefit from. To this the Rambam says that the issur to eat and the issur to benefit aren't independent entities, rather the prohibition to benefit is an extension of the issur to eat (we see a similar concept in succah 35a by an esrog that is forbidden to eat where rashi writes that it doesn't qualify as לכם. Rashi explains that "lachem" implies that you can benefit from it in all ways - an esrog that is forbidden to eat is missing a major source of benefit). Based on this Rambam, the issur to benefit isn't considered a new issur to cause the issur achila to be binding, and the dagul m'rvava therefore proves from here that even the issur to benefit itself wouldn't be binding. There is a lot of discussion about this Rambam because he seems to say that the approach only works because there isn't an independent source to forbid benefiting from meat and milk, yet in sefer hamitzvos he writes himself that the third repetition of לא תבשל גדי בחלב אמו is an independent source to forbid benefit.

Chulin 103b - Rules of Eating to violate Eiver Min Hachai

The gemara (according to Rashi) has two versions of R. Yochanan as to whether the concept of כדי אכילת פרס applies to אבר מן החי, like it would by all other issurim. On the top of the page the gemara assumed that it would not apply, and on the bottom of the page when it deals with eating a half kezayis and then another half kezayis, assumes that it does.The rationale that אבר מן החי would be different and not have this halacha l'moshe misinai is that even inedible foods combine to the shiur of kezayis. Since אבר מן החי is a chiddush, the halacha l'moshe misinai that allows us to combine all eating within כדי אכילת פרס wouldn't apply to a chiddush case. Without the concept of כדי אכילת פרס the gemara assumes that the entire kezayis must be consumed בבת אחת, but then enters a discussion as to what would qualify as בבת אחת - at one time.

There seem to be three opinions in the gemara what would qualify as בבת אחת, and is dependent on the definition of אכילה. R. Yochanan considers eating to be a function of הנאת גרונו - the mouth. Reish Lakish considers eating to be a function of הנאת מעיו - the stomach. Therefore, R. Yochanan will say that as long as there is a kezayis in the mouth at one time, it is considered בבת אחת, whereas Reish Lakish will say that a kezayis must be swallowed at one time (Rashi explains that it is not possible to chew a kezayis and swallow it all at once since it will naturally begin to slip down his throat, so the only way to swallow a full kezayis would be without chewing. Rashi also seems to hold that swallowing something which is normal to chew wouldn't constitute דרך אכילה, therefore the gemara is forced to make the case of גרומיתא זעירתא which is normal to be swallowed without chewing).

Within the opinion of R. Yochanan that it only qualifies as בבת אחת if a kezayis enters the mouth at the same time, Rashi and Tosafos argue whether we require the kezayis to literally be one unit when it is put into the mouth (tosafos), or whether it can be cut in half so long as there will be a full kezayis in the mouth at one time (rashi). Similarly, they will argue in the opinion of Reish Lakish. Rashi should only require a kezayis in the stomach at the same time, even if it were swallowed in parts (this is actually tosafos question on rashi because reish lakish seems to hold that a full unit of kezayis must be swallowed at one time), whereas Tosafos requires a full unit of a kezayis to be swallowed at one time.

However, according to R. Elazar both Rashi and Tosafos would agree that if one would eat a half kezayis and after a slight pause eat another half, it would qualify as an eating בבת אחת to be chayev. The concept of כדי אכילת פרס would have only permitted the pause to be longer between the two half kezaysim. Since we don't apply כדי אכילת פרס, the pause must be very slight - רש"י - שנתרחקו זה מזה מעט.

The Rambam (Ma'achalos Ha'asuros 5:3-4) has a very different approach in this gemara. Firstly, the Rambam understands that the case of חלקו מבחוץ is not when one eats a half kezayis and then another half kezayis as rashi says, nor is it a case where one splits the kezayis in half and puts both halves in his mouth together as Tosafos says. Rather, the case is where he separates the meat from the bone so that it is no longer one unit. The Rambam understands that the chiddush ha'torah which allows you to combine the bones to make up the kezayis only applies when the integrity of the limb is maintained. As soon as one separates the meat from the bone, the bones are no different than bones by other issurim which don't qualify as an eating. Therefore, the case of חלקו מבפנים that you are going to be chayev is when one puts the meat in his mouth with the bone, and only in his mouth do they separate from one another. Since they were placed in his mouth together, they combine.

The Rambam also holds that paskening like R. Elazar wouldn't undermine the assumption of R. Yochanan. R. Elazar who allows one to be chayev even if they would break the eiver into pieces and eat a half kezayis and then another half, would only apply if ultimately he ate a full kezayis of MEAT. Therefore, if he actually ate a full kezayis of meat, he is chayev even though he separated the meat from the bone and ate it little by little (even with slight pause in between) which is the halacha of R. Elazar. But, in order to combine the bones with the meat to fill the shiur of kezayis, he must place the bone in his mouth together with the meat and together they must make up a kezayis - which is the halacha of R. Yochanan. In other words, the Rambam understands that R. Elazar takes issue with the definition of eating בבת אחת that R. Yochanan establishes by relaxing the requirement of putting it in one's mouth together (when there is no need for bones to be considered toward the kezayis), but agrees with the din of when bones can be combined - only when they are together with the meat at the time they are consumed.

Chulin 102a - Eiver Min Ha'chai

The gemara says that even though the prohibition of אבר מן החי for a Jew may only apply to kosher animals (acc. to chachamim and R. Meir), for a goy it will apply even to non-kosher animals. Tosafos 33a questions how this can be. Wouldn't this be a violation of the rule that there is nothing prohibited to a goy that is permitted to a Jew - ליכא מדעם דלישראל שרי ולעכו"ם אסור. Tosafos says that since there would be a prohibition for the Jew to eat a non-kosher animal, even though it wouldn't be considered אבר מן החי, it would not violate the principle of something being permitted to a Jew and prohibited to a goy. Tosafos holds that the prohibition on the goy doesn't have to be the same prohibition on the Jew so long as there is some prohibition (R. Akiva Eiger in a teshuva 165 qualifies this idea and says that it would only be when the prohibition on the Jew is a lack of shechita such as a non-kosher animal, to the exclusion of a treifa where it has already been shechted properly and has not relation to the issur of eiver min ha'chai).

It seems to me that Rashi in our sugya is also addressing the same question. Rashi writes -

אבל בן נח מוזהר על הכל, דכל דקרינא ביה בשר לחודיה אכול, קרינא ביה אבר מן החי לא תאכל. Rashi says that whenever it is permitted to eat the meat after being killed, there is an issur of eiver min ha'chai to eat the meat prematurely. Perhaps rashi understands that the principle of there is nothing prohibited to a goy that is permitted to a Jew isn't violated here because the same exact principle that applies to the goy - don't eat alive what you can eat dead, applies to the Jew. The only difference is that the Jew cannot eat non-kosher animals when dead so there is not issur of אבר מן החי when it's alive, but for the goy there is. Since the principle applies equally to the Jew and goy it wouldn't violate the rule of ליכא מדעם דלישראל שרי ולעכו"ם אסור.

Chulin 101b - The Two Prohibitions of Yom Kippur

Rashi explains that when the gemara tries to prove that R. Yossi Haglili holds of איסור כולל from the fact that when yom kippur falls on shabbos and he does melacha he has to bring a korban both for shabbos and for yom kippur. Even though YK and shabbos are entering at the same time, one can only be liable for both since if theoretically one would start before the other, each can be binding on top of the first. Rashi explains that even if shabbos would enter prior to YK, the prohibition of YK would be binding on top of shabbos as an איסור כולל. The fact that YK forbids not only doing melacha, but also eating and drinking makes it an איסור כולל to allow the prohibition of melacha to be binding on top of the prohibition against doing melacha on shabbos - מיגו דאיתסר באכילה משום יוה"כ איתסר ליה נמי מלאכה משום יוה"כ. The difficulty of this rashi is how can we say an איסור כולל from the issur to eat to the issur to do melacha, they are totally separate prohibitions. From rashi we learn a new approach in understanding the nature of the issur to eat and to do melacha on YK. Although in the counting of mitzvos they are completely independent, and would seemingly be two completely separate prohibitions that apply on the 10th of Tishrei, that is not how rashi is viewing it. Rather, the kedusha of YK results in two halachos, one is a prohibition of eating and the second is the prohibition of melacha. Both are outgrowths of the kedushas ha'yom and not independent prohibition that apply to the calendar date of 10th of Tishrei. It would now make sense that Rashi can consider YK in the general sense to be an איסור כולל from eating to melacha, since both are merely outgrowths of the kedusha of YK.

I would like to suggest that the Rambam would not agree with rashi. Rambam (Hil. Shevisas Asor 1:6) writes that the mitzvah d'oraysa to add to YK before and after is limited to YK (not shabbos and yom tov) and limited to the עינוי of YK, it doesn't extend m'doraysa to the issur melacha. The Minchas Chinuch clearly understands the Rambam this way. The Rambam would seem to hold that m'doraysa when one is me'kabel YK early, they are prohibited from eating but not prohibited from doing melacha. The fact that by accepting kedushas ha'yom one can be prohibited from eating but not from melacha implies that the they are not an outgrowth of the kedushas ha'yom, rather two independent halachos that apply on the 10th of Tishrei and could theoretically exist one without the other.

Chulin 99b - Bitul in more that 60x

The Rama (y.d. 98) writes that foods with a very strong flavor such as spices are not batul in 60x because the flavor is still able to be tasted, however the Rama limits this to when the item is prohibited in and of itself (i.e. teruma or avoda zara), to the exclusion of spices that just have a non-kosher item absorbed in it. The source for the Rama is our gemara where we see that "grissin" which fall into lentils can give flavor even if there is 100x as much to be mevatel. Clearly, the idea of 60x is an assumption but doesn't apply to cases where the flavor is actually tasted. But, regarding the Rama's stipulation that this rule would not apply to foods that have the taste of issur absorbed in them, but are not assur themselves, the Gr"a quotes those who disagree. The Gr"a writes that in our gemara we find that fish brine isn't going to be batul until there is 192x as much, even though the actual water and vinegar in the brine isn't technically assur, just that it has the flavor of the fish fat absorbed inside of it. The same should apply to a spice which has the flavor of non-kosher meat - so long as the spice could be tasted in whatever dish it falls into, it should be assur even if there is 60x as much.

The Shach writes that when spices are able to assur foods even when there is more than 60x, it is only an issur d'rabonon. R. Akiva Eiger quotes the Ran who disagrees and holds that it would be d'oraysa. The Ran is easy to understand, but the Shach is harder to understand - why would it only be d'rabonon? It seems that the Shach understands that once there is 60x of the mutar food to the assur food, the flavor is weakened to a point that it isn't considered true ta'am and therefore it is only assur m'drabonon.

Chulin 99b - Gid Hanashe is Prohibited to Derive Benefit From

The gemara has a discussion in Pesachim about things that are prohibited to eat, whether they should also be prohibited to derive benefit from. Either way, one of the approaches to understand the nature of issurei achila - things that are prohibited to eat, is that it is essentially a prohibition to derive benefit, but the Torah only forbids the epitome of benefit from the item - eating. Meaning, that the nature of issur achila is that it is prohibited to derive the benefit that this item is meant to provide which is the benefit of eating. This would explain for example why we wouldn't consider an achila gassa (over eating), or eating of something which taste bad to be a violation of eating, since there is no pleasure or benefit associated with that eating. 

However, Tosafos makes a calculation in our sugya that undermines this premise. Tosafos proves from the gemara in Pesachim that according to the opinion who considers giddin (sinews) to have flavor, it is only prohibited to eat. But according to the opinion who doesn't consider it to have flavor, it is even prohibited to derive benefit from. Since we rule that Gid Ha'nashe doesn't give off flavor, we must rule that one cannot derive benefit from it - therefore it cannot be gifted to a goy, if the presence of the gid hanashe will raise the stature of the gift. Now, if one were to eat gid hanashe they would certainly be in violation of the prohibition to eat gid hanashe, even though there is no flavor so that they cannot be in violation of the issur to derive benefit. If it were true that the prohibition to eat is a form of deriving benefit, one couldn't be in violation of eating gid hanashe since there is no benefit and would only be in violation on selling or giving to a goy in which there is benefit. The fact that one is in violation even for the eating of gid hanashe which has no flavor, indicates that eating is in no way contingent on the pleasure or benefit one receives from the food, rather it is an act that the Torah forbids regardless of the benefit it provides.

Chulin 94b - Rules of Geneivas Da'as

The gemara on amud alef has three answers to explain the mishna. Tosafos writes that according to the first answer of the gemara that the mishna is speaking in a place where they call out so it is permitted to purchase from a goy, the mishna would contradict the braisa. To reconcile the contradiction Tosafos is forced to distinguish between a sale and a gift - only by a sale where money is being paid is there an issur of g'neivas da'as. However, according to the second and third answer Tosafos says that only when you explicitly lie is it considered g'neivas da'as, but if you just do something where the other party draws his own conclusion it would be considered איהו הוא דקא מטעי נפשיה (as we see in the gemara and isn't considered gneivas da'as). Tosafos modifies this slightly by saying when one does an action that is suggestive such as opening up a barrel of wine in the presence of the guest indicating that it is in his honor, that is tantamount to actually saying that you are doing it for him. Rashi seems to maintain that once the gemara introduces the concept of איהו הוא דקא מטעי נפשיה, we limit ALL the cases of geneivas da'as to where he explicitly told the person that he is doing it for him, or explicitly told the person that it was shechted meat. We see from here that one is not obligated to correct his friends misunderstanding of the situation, but cannot actively mislead him.

Chulin 94a - Geneivas Da'as

The gemara in trying to figure out the p'shat in the mishna that prohibits sending meat from which the gid ha'nashe was removed to a goy, offers a few explanations. The final explanation is that it is a violation of geneivas da'as. Being that the first two answers are able to explain the mishna without inventing a concept of geneivas da'as, perhaps we shouldn't pasken like the approach that relies on this concept. The Rosh takes this approach and rejects the notion of geneivas da'as when one sends a gift to a goy, such as the case in the mishna and limits the problem of geneivas da'as specifically to a sale. With this he is able to work out the various other sources that indicate geneivas da'as is a real prohibition, but rejects applying the concept to the case of the mishna since it was being sent as a gift rather than a sale (עיין במעדני יו"ט ס' ר' שמוכיח מהש"ס שאין חילוק בין מכר למתנה). It would seem from the Rosh's approach that geneivas da'as applies to a sale but not a gift, that it is essentially an offshoot of the prohibition to steal. When one is giving a gift and not receiving anything in return as part of the compensation, it cannot be considered stealing. But, when one is receiving some level of compensation, it is prohibited to fool the buyer since the entire compensation is now being given under a false pretense (even though the buyer may have paid the same price even had he known the truth).

In my opinion there are 3 approaches to the nature of the issur of geneivas da'as. The Rosh holds that it is an offshoot of actual theft. Rashi and the Rambam reject the approach of the Rosh, yet differ in how they portray the issur.

Rashi writes  multiple times in the sugya - ונמצא מחזיק לו טובה חנם. This implies that the prohibition is not stealing the compensation because rashi uses this logic even in the case of a gift where there is no compensation. Rather, the prohibition is not at the time of the geneivas da'as, it is violated afterward when you accept the goodwill of the receiver and his interest in responding in kind for something that he thinks you did for him, when in truth you didn't do for him as much as he thinks you did. It would seem from rashi that if one would notify the goy immediately after the violation of the geneivas da'as before he will have feelings of goodwill, he will avoid the entire prohibition. The issur is not in fooling the goy, nor is it in stealing compensation for the goy, but is is accepting his goodwill.

The Rambam in Hil. Dei'os 2:6 has what would be considered the simplest approach to the nature of geneivas da'as. The Rambam writes

אסור לאדם להנהיג עצמו בדברי חלקות ופיתוי, ולא יהיה אחד בפה ואחד בלב אלא תוכו כברו והענין שבלב הוא הדבר שבפה, ואסור לגנוב דעת הבריות ואפילו דעת הנכרי, כיצד לא ימכור לנכרי בשר נבילה במקום בשר שחוטה, ולא מנעל של מתה במקום מנעל של שחוטה וכו' ואפילו מלה אחת של פתוי ושל גניבת דעת אסור, אלא שפת אמת ורוח נכון ולב טהור מכל עמל והוות

The Rambam considers the prohibition to have nothing to do with the subject of the geneivas da'as. It is a violation of the מידת האמת that is expected of a Jew, and by lying to the anyone, even a goy, he is undermining this essential midah of being truthful. The difference between the Rambam and Rashi is that according to Rashi the prohibition exists because of the outcome of the undeserved goodwill that the Jew will receive from the goy, whereas according to the Rambam the issur is the act of deceiving another human being.