1) "ROV" VERSUS "KAROV" IN THE CASE OF A "RUBA D'LEISA KAMAN"
QUESTION: The Gemara quotes a Beraisa in which Rebbi Chiya states that Dam that is found in the "Prozdor" is assumed, mid'Oraisa, to be Dam Nidah which came from the "Mekor," because most Dam is located in the "Mekor" (as opposed to the "Aliyah"). The principle of Rov dictates that the Dam must be considered to have come from the "Mekor."
Is this Rov -- which indicates that the Dam came from the "Mekor" -- a "Ruba d'Leisa Kaman" or a "Ruba d'Isa Kaman"? A "Ruba d'Leisa Kaman" is a majority in frequency -- something usually occurs in this manner. The majority is not present and countable, but is a predictable consequence of natural events. For example, there is a Rov that "most animals are not Tereifos." This Rov is not present, but there nevertheless exists a fact that most animals are born healthy.
A "Ruba d'Isa Kaman," on the other hand, refers to a situation in which the Rov is physically present. For example, when one piece of Tereifah meat became mixed with two pieces of Kosher meat, the Rov (the two pieces of Kosher meat) is present. This type of Rov is considered more powerful than a "Ruba d'Leisa Kaman."
If it is a "Ruba d'Leisa Kaman" that determines that the Dam came from the "Mekor" and is Dam Nidah, then it can be deduced from Rebbi Chiya's statement that Rov overrides Karov even when the Rov is a weaker form of Rov, a "Ruba d'Leisa Kaman."
ANSWER: TOSFOS (DH v'Shama, in the "Hagahah," or, according to an alternative Girsa, in DH Hachi Garsinan) says that this Rov is considered a "Ruba d'Leisa Kaman." Tosfos asserts that if the Rov was a "Ruba d'Isa Kaman," Rava would not have needed to infer from Rebbi Chiya's statement that the principle of Rov is mid'Oraisa. It is obvious that the normal form of Rov, "Ruba d'Isa Kaman," is mid'Oraisa, as the verse states explicitly, "Acharei Rabim l'Hatos" (Shemos 23:2). From the fact that Rava needs Rebbi Chiya's statement to prove that a Rov is mid'Oraisa, it is clear that he is referring to a "Ruba d'Leisa Kaman," which is not necessarily learned from the verse. (See MAHARSHA.)
According to Tosfos who says that Rebbi Chiya's case is a case of a "Ruba d'Leisa Kaman," it follows that even such a Rov overrides a Karov.
(The Acharonim infer from the RAMBAM, however, that he maintains that a "Ruba d'Leisa Kaman" does not override a Karov. The Acharonim explain that the Rambam does not rule in accordance with the statement of Rebbi Chiya (PLEISI #63, ZICHRON YEHOSEF as cited by the PISCHEI TESHUVAH YD 48:14).)
Why, though, is the case of Rebbi Chiya considered a "Ruba d'Leisa Kaman"? Since the Dam of the "Mekor" is more abundant than the Dam of the "Aliyah," it should be considered a "Ruba d'Isa Kaman," since the body is present, and in the body there is a majority of Dam in the "Mekor" and a minority of Dam in the "Aliyah." (SHEV SHEMAITSA 4:1, CHIDUSHEI CHASAM SOFER)
1. The SHEV SHEMAITSA answers that had this Rov been based on the fact that there is more Dam in the "Mekor" than in the "Aliyah," then indeed this Rov would have been considered a "Ruba d'Isa Kaman." However, this Rov cannot be based on the abundance of Dam in the "Mekor." The fact that there is a greater amount of Dam in the Mekor cannot be considered a Rov because it is a case of "Kavu'a" in which Rov does not apply ("Kol Kavu'a k'Machtzeh Al Machtzeh Dami"). Rather, the Rov here is based on the fact that Dam flows more frequently from the "Mekor" than from the "Aliyah." This Rov is a "Ruba d'Leisa Kaman" (as per the above definition).
The SHA'AREI YOSHER (4:3, DH Lachen) challenges the Shev Shemaitsa's proof that the Rov in this case is not a "Ruba d'Isa Kaman." The concept of "Kavu'a" cannot determine the origin of the Dam because "Kavu'a" does not resolve a question that concerns an event that happened (in this case, whether or not the Dam separated from the "Mekor"). The Sha'arei Yosher agrees, however, that there is a Rov that the majority of Dam comes from the "Mekor" (which is a "Ruba d'Isa Kaman"), and that there is another Rov -- a "Ruba d'Leisa Kaman" -- that Dam flows more frequently from the "Mekor" than from the "Aliyah."
2. The CHASAM SOFER answers that this Rov is considered a "Ruba d'Leisa Kaman" because it is not certain that this woman has any Dam at all in her "Mekor," and thus there certainly is no Rov that indicates that a majority of her Dam is in her "Mekor." Rather, the Rov is based on the fact that women in general have more Dam in their "Mekor." This is a "Ruba d'Leisa Kaman," because the majority is not present and countable, and the Rov is merely a predictable consequence of natural events.
The KOVETZ SHI'URIM argues with the Shev Shemaitsa's explanation of the difference between a "Ruba d'Isa Kaman" and a "Ruba d'Leisa Kaman." The Shev Shemaitsa understands the difference to be based on whether the Rov is present and countable. However, there is another difference between a "Ruba d'Isa Kaman" and a "Ruba d'Leisa Kaman." In the case of a "Ruba d'Isa Kaman," the nature of the majority can be determined based on all of the individual details. In contrast, in the case of a "Ruba d'Leisa Kaman," knowledge of the general situation indicates what the situation is in each specific case. For example, there is a Rov that most animals are Kesheros. That is knowledge of the general situation, which then can be applied to a specific situation to determine that a certain animal is part of the Rov and is kosher. According to this, the Rov in Rebbi Chiya's case is a "Ruba d'Leisa Kaman" since the Rov is not based on an actual measurement of the amount of Dam in the "Mekor" compared with an actual measurement of the amount of Dam in the "Aliyah." Rather, it is based on general knowledge that, normally, a majority of Dam is in the "Mekor." (I. Alsheich)
24b----------------------------------------24b
2) A TREE PLANTED NEAR A CITY
QUESTION: The Mishnah states that one is forbidden to plant a tree within twenty-five Amos of a city. If a person does plant a tree in that area, he must cut down the tree. If the city preceded the tree, then he is not reimbursed for his tree, but if he planted the tree first and then the city was built, he is entitled to be reimbursed for his tree. When there is a doubt as to whether the city was there first or the tree was there first, the owner of the tree must cut down his tree and, due to the doubt, he does not receive reimbursement for his tree.
The Gemara asks why this case differs from a case in which a person's tree is within twenty-five Amos of his neighbor's Bor, and there is a doubt whether the tree preceded the Bor or vice versa. In such a case, the Mishnah (25b) says that the owner of the tree is not required to cut down his tree.
The Gemara answers that in the case of the tree and the city, the owner of the tree is obligated to cut down his tree regardless of whether it was there first; the only question is whether he receives reimbursement for his tree (and since it is a Safek, he cannot exact compensation without proof that his tree was there first). In the case of the tree and the Bor, the owner does not have to cut down his tree if his tree was there first, and, therefore, he is not required to cut down his tree in a situation of doubt.
Why does the Gemara here not give the same answer it gives to an earlier question? Earlier, the Gemara explains that there is a difference between a privately-owned Bor and a publicly-owned city; if damage is caused to a publicly-owned city, the Halachah is more stringent and requires the owner of the tree to cut it down. Why does the Gemara not give this answer here? (GILYON TOSFOS, cited by TERUMAS HA'DESHEN #341)
ANSWERS:
(a) The GILYON TOSFOS writes that the Gemara indeed could have given this answer, but it preferred to give a better answer.
(b) The MAHARAM MI'ROTENBURG writes that the earlier answer -- that there is a difference between a privately-owned Bor and a publicly-owned city -- cannot be used to answer the Gemara's question here. The Gemara here asks that when a tree was planted near a Bor and there is a doubt as to which came first, the owner of the tree should not be required to cut down his tree because "ha'Motzi me'Chaveiro Alav ha'Re'ayah" -- the owner of the Bor must prove that his Bor was there first. The Gemara asks why the Halachah is different in the case of a tree planted near a city, when there is a doubt as to which came first. In this case, too, the owner of the tree should be able to say to the residents of the city that he will cut down his tree (without reimbursement) only when they prove that the city was there first. Until they bring proof, he should not be obligated to cut down his tree, in accordance with the general principle of "ha'Motzi me'Chaveiro Alav ha'Re'ayah." With regard to this principle, there would be no difference between a privately-owned Bor and a publicly-owned city. (I. Alsheich)