When a chicken lays an egg, its ovary first releases a yolk (the process taking around 30 minutes). As it travels down the oviduct, a thin membrane and then the albumen (egg white) is added (3 hours). It continues traveling, assuming an oval shape and obtaining a double-membrane (1 hour). It enters the uterus and the shell is created (20 hours). A bloom is applied to the shell’s surface (1 hour), and then the hen lays the egg (20-30 minutes). The process takes about 26 hours, so each day the egg is laid two hours later. Hens don’t lay at night, so eventually, this resets to the early morning. Thus, an egg laid on one day was begun—indeed, almost finished—on the preceding day. (See Rabba, Beitza 2b.)
Masechet Beitza begins by discussing the law of an egg laid on Yom Tov. Bet Shammai are uncharacteristically lenient, saying one may eat it that day, while Bet Hillel maintain it is prohibited. Amoraim proffer differing explanations for these positions.
Outside of Israel, in Babylonia, there are two days of Yom Tov, and the unique question arises (4b) of whether an egg laid on the first day may be eaten on the second, predicated on whether the second day is due to doubt as to the true day, in which case it would be permitted (Rav) or whether it is simply instituted as one long day, in which case it would be forbidden (Rav Asi, first-generation Babylonian Amora). However, in terms of the two-day Rosh Hashanah, Rav and Shmuel (extremely influential first-generation Babylonian Amoraim) both adopt Rav Asi’s position that the egg is forbidden (5a), implicitly because they consider it a single long day.
Much of this daf’s dynamics depends on the participants’ biographical backgrounds. Rabba (b. Nachmani, third-generation Amora) brings evidence from a Mishnah in Rosh Hashanah that the intent of Rabban Yochanan b. Zakkai (second-generation Tanna) in decreeing two days of Rosh Hashanah after the destruction of the Temple was as doubt, rather than as a long day. Abaye (fourth generation), his nephew/student, objects. How could Rabba argue against a unanimous Rav and Shmuel?! Rav and Shmuel are extremely prominent first-generation Amoraim, and a third-generation scholar cannot simply ignore them. Rabba replies, “I tell you Rabban Yochanan (b. Zakkai), and you tell me Rav and Shmuel?” That is, Rabba is citing (/interpreting) a second-generation Tanna, and moreover, the very fellow who established the edict. If anything, it is a problem for Rav and Shmuel!
The Talmudic Narrator then resolves how Rav and Shmuel can disagree, saying הָא לַן וְהָא לְהוּ, “this is for us and that is for them.” The Mishnah targets Israel, where Rabban Yochanan b. Zakkai’s edict and his doubt reasoning holds, while Rav and Shmuel, Amoraim of Bavel, addressed Babylonia, where the ancient edict and its lengthy-day reasoning holds. This bifurcated approach is used by Rava to harmonize two braytot (see Beitza 14b, about grinding with a mortar and pestle on Yom Tov, and Sukkah 36a, about using a Cushite etrog, while each time his disputant Abaye adjusts the meaning of one brayta), and by Rav Amram to resolve contradictory statements by two Amoraim (Rabbi Yochanan/Shmuel on Kiddushin 29b of whether to marry or learn Torah first, and Rabbi Yochanan/Rav Chisda on Berachot 44b on whether to reference “its fruits” in the blessing after fruits of the Land), where cultural and practical differences lead to a different ruling. The Talmudic Narrator uses this in many other instances, including here, instead of leaving a difficulty or suggesting that Rav and Shmuel understood that Mishnah differently.
Tosafot raise a strong point. In Eruvin 39a, Rabbi Yossi (fourth-generation Tanna) also maintains that for Rosh Hashanah, an egg laid on the first day may not be eaten on the second day. Since Rabbi Yossi lived after the destruction, he wouldn’t reference the earlier edict, which had no practical purpose. What was, was! Since he lived in Israel, he wouldn’t reference the Babylonian practice. One wouldn’t say הָא לַן וְהָא לְהוּ. They suggest that Rabbi Yossi addressed the pre-destruction edict, and it was still relevant since that understanding impacted Babylonian practice. Yet, I think an alternative is that Rav and Shmuel understood the Mishnah differently from Rabba and agree with Rabbi Yossi.
We should point out that in Eruvin, Rabbi Yossi explains a dispute between Rabbi Eliezer (b. Hyrcanus, third-generation Tanna, before and after the Temple) and his contemporaries, so a Temple-era edict makes sense. Further, Rabbi Yossi was ordained in defiance of a Roman decree and fled to Asia Minor until the decree was lifted (Bava Metzia 84a), so he has connections to Chutz LaAretz. Also, a Mishnah stated that they fashioned a ramp to protect the scapegoat from Babylonians, who would pluck at its hairs and say “take our sins and go.” When Rabbi Yehuda (Yoma 66) says it was actually Alexandrians, Rabbi Yossi tells him “you have comforted me,” which implies (Rashi) that his family was from Babylonia. However, after a Mishnah informs that when Yom Kippur occurred on Friday the Babylonian priests would eat the goat sacrifice on Friday night raw, Rabbi Yossi says it was Alexandrians, and Rabbi Yehuda is comforted (Menachot 100a). Likely one sugya is flipped due to a scribal error.
Rabbi Dr. Joshua Waxman teaches computer science at Stern College for Women, and his research includes programmatically finding scholars and scholastic relationships in the Babylonian Talmud.
