A PARTIAL BECHOR
(Mishnah - R. Tarfon): If a firstborn was born Yotzei Dofen (through Caesarian section), and the next animal (from this mother) was born normally, both of them graze until they get a Mum, then the owner eats them;
R. Akiva says, neither is a Bechor;
The first is not a Bechor because it is not Peter Rechem (the first to leave the womb);
The second is not a Bechor because another animal was born to this mother before it.
Question: What do they argue about?
Answer: R. Tarfon is unsure whether a partial Bechor (i.e. in only one respect, it was the first offspring or the Peter Rechem) is a Bechor. R. Akiva is sure that it is not a Bechor.
(Beraisa) Question: What is the method of expounding Klal ha'Tzarich li'Frat (a general term that cannot be understood without a specific term) and a Prat ha'Tzarich li'Chlal (a specific term that cannot be understood without a general term)?
Answer - Suggestion #1: Perhaps "Kadesh Li Chol Bechor" includes females!
Rejection: It says "Zachar."
Suggestion #2: Perhaps "Zachar" teaches that the first male born is a Bechor, even if females were born before it!
Rejection: It says "Peter Rechem."
Suggestion #3: Perhaps "Peter Rechem" teaches that the first animal to leave the womb is a Bechor, even if a previous animal was born Yotzei Dofen!
Rejection: It says "Bechor."
Question (Rav Sheravya): The Tana did not refute Suggestion #2 by saying that a male born after a female is not "Bechor". This implies that a partial Bechor is a Bechor;
To refute Suggestion #3, he says that an animal born after a Yotzei Dofen is not "Bechor". This implies that a partial Bechor is not a Bechor!
Answer #1 (Abaye): He holds that a partial Bechor is not a Bechor;
Suggestion #2 really means 'perhaps "Zachar" teaches that if the firstborn is a male it is a Bechor, even if it was Yotzei Dofen!'
Answer #2 (Ravina): He holds that a partial Bechor is a Bechor. Even so, "Bechor" refutes Suggestion #3;
If an animal born after a Yotzei Dofen would get Kedushas Bechor, there would be no need for the Torah to write "Bechor"!
It is not needed to exclude when a female was born previously. Peter Rechem excludes this!
Conclusion: "Bechor" teaches that an animal born after a Yotzei Dofen does not get Kedushas Bechor.
Objection (Rav Acha mi'Difti): If a partial Bechor is a Bechor, the simple meaning of "Bechor" does not exclude a partial Bechor, just it may be expounded to exclude (the most reasonable case to exclude);
Indeed, we would exclude a male born normally after a male Yotzei Dofen ("Bechor" is extra to exclude this case, for it is a Bechor with respect to the womb, but not with respect to males);
However, we would not exclude a normal male after a female Yotzei Dofen (for the male is a Bechor with respect to the womb and with respect to males).
Rather, we must answer like Abaye.
WHEN ARE WE CONCERNED FOR BECHORAH?
(Mishnah - R. Yishmael): If Reuven bought an animal from a Nochri. and does not know whether it already gave birth (and now it gave birth to a male):
If (it was) a goat (and it) gave birth in its first year, he gives the kid to a Kohen. (It is surely a Bechor.) If it gave birth after this, it is a Safek. (It grazes until it gets a Mum, and then Reuven eats it);
If a sheep gave birth within two years, he gives the lamb to a Kohen. If it gave birth after this, it is a Safek;
If a cow gave birth within three years, he gives the calf to a Kohen. If it gave birth after this, it is a Safek;
R. Akiva: If the Halachah were that only a proper child exempts from Bechorah, you would be right;
However, Chachamim taught that Tinuf (a dissolved fetus; alternatively, bubbles of blood) in a small animal is a sign of a (miscarried) child. (It exempts from Bechorah.) A Shilya (fetal sac) in a large animal is a sign of a child;
In a woman, Shapir (skin in the form of a child) and Shilya are both Simanim of a child (regarding Tum'as Yoledes).
The general rule is, if we know that an animal previously gave birth (or miscarried), the Kohen does not receive anything (from the next birth);
If we know that it did not give birth before, the Bechor belongs to the Kohen;
If we do not know whether or not it gave birth before, the owner eats it when it gets a Mum.
(Gemara) Question: Why does R. Yishmael say that after one year, it is a Safek? The majority of goats become pregnant and give birth in their first year. We should follow the majority and say that a kid born after one year is definitely not a Bechor!
Answer #1: R. Yishmael holds like R. Meir, who is concerned for the minority.
Answer #2: He can hold like Chachamim;
Chachamim follow a majority d'Isei Kaman (everything is in front of us), such as the majority opinion of judges on the Sanhedrin, or the majority of stores in the city (to determine whether meat found in the street is Kosher or Nevelah);
They do not follow a majority d'Leisei Kaman (not in front of us, i.e. a statistical majority, e.g. that most goats in the world give birth in their first year).
Objection: Chachamim follow a majority d'Leisei Kaman regarding minors!
(Beraisa - R. Meir): A (minor) boy or girl may not do Yibum or Chalitzah.
Chachamim: We agree that a minor may not do not Chalitzah. It says "Ish," and the Torah equates the Yevamah to the Yavam;
However, why do you forbid Yibum?
R. Meir: We are concerned lest he or she is a Seris or Ailonis (one who will not develop to be a normal male or female. In such a case, there is no Mitzvah of Yibum. The "Yibum" is merely marrying a sister-in-law, which is Chayavei Kerisus.)
Chachamim are not concerned for this. They follow the majority (most people are normal).
Conclusion (Rava): We must say that R. Yishmael holds like R. Meir.