Literary critic Adam Kirsch is reading a page of Talmud a day, along with Jews around the world.Since the current cycle began in August 2012, Daf Yomi readers have been making our way through Seder Moed, the division of the Talmud devoted to holidays: Shabbat, Pesach, Yom Kippur, Sukkot. This week, however, we began Tractate Beitzah, which is not the name of a holiday but, oddly enough, the Hebrew word for “egg.” What sort of holiday is Egg? In fact, the alternative title for this tractate is simply “Yom Tov,” the generic term for holidays or festivals, and it covers features of Jewish law that are in force for all the holidays.The tractate has come to be called Beitzah because that is its very first word, and just as advertised, the pages we read this week were entirely devoted to eggs. “An egg that is laid on a holiday,” chapter 1 begins: What is its legal status? As always when the Talmud seems to be focusing on a trivial issue, the rabbis are not interested in eggs per se, but in the concepts that this particular question brings to light. In this case, we are dealing with our old friend muktzeh, a legal category that was dealt with extensively in tractates Shabbat and Eruvin.Muktzeh means “set aside,” and it designates a kind of object that cannot be moved or used on Shabbat or a holiday. Muktzeh is a good example of the rabbinic admonition, famous from Pirkei Avot, to “make a fence around the Torah”: The rabbis would introduce laws of greater strictness than the Torah’s own in order to reduce the chance that a Torah law might be violated. Thus the Torah calls for avoiding certain broad categories of work on Shabbat and holidays, and muktzeh broadens the prohibition to include any object that is not specifically prepared in advance for use on the holy day. By avoiding everything “set aside,” we lessen the chance that we will come to carry an object or do work with it.One category of muktzeh is the “just born”—something that comes into existence on the holiday itself. Naturally, such an item cannot possibly have been intended in advance for use on the holiday, since it didn’t exist yet. A newly laid egg would seem to be such an object: Is it muktzeh, or are you allowed to eat it? (Insofar as I understand the complicated rules of muktzeh, I believe this questionwouldn’t arise on Shabbat, because food preparation is generally forbidden on Shabbat, while it is permitted on holidays. That is why the egg problem is raised here rather than in Tractate Shabbat.)The first mishna on Beitzah 2a gives us the competing answers of Beit Hillel and Beit Shammai. Almost always when these two schools of thought disagree, Shammai is the more stringent and Hillel the more lenient; but in this case they change places. Beit Hillel rules that an egg laid on a holiday may not be eaten, while Beit Shammai allows it. The reasons behind this ruling turn out to be exceptionally complex, and the next six pages of Gemara are devoted to unraveling them.To answer the egg question, the Gemara turns, logically enough, to a chicken question. What is the status of the chicken that laid the egg? Here the principle turns out to be rather counter-intuitive. You might think that if you designate a chicken in advance for laying eggs, and it then lays an egg on the holiday, you could eat that egg, since it was in a sense expected. In fact, the reverse is true: If a chicken is designated for laying eggs, then the chicken itself was not intended to be eaten, and so it is muktzeh. According to Beit Hillel, then, the egg that emerges from it is also muktzeh, since a product shares the status of its producer. Conversely, if the chicken was designated for cooking and eating, but before it’s slaughtered it happens to lay an egg, that egg is considered merely a separated portion of the chicken, and so it too is edible.As often happens in the Talmud, the issue at stake here is how to define a substance: Is the egg its own entity, or is it part of something else? At what point does it make the transition from one state to the other? Later in the discussion, the rabbis try to clarify the question by using analogies from other areas of law. In Tractate Eruvin, for instance, the rabbis rule that fruits that fall from a tree on Shabbat are “just-born,” and so they are muktzeh. Is an egg that emerges from a chicken like a fruit that falls from a tree? Not quite, Abaye objects: The point of the fruit rule was not that the fruit itself shares the status of the tree. Rather, it was a secondary decree, designed by the rabbis to discourage people from picking fruit on purpose, which is a clear Shabbat violation. But this logic doesn’t apply in the case of eggs, since you can’t pick an egg as you can an apple.Rabbi Yitzchak raises another analogy: Perhaps the newly laid egg is like juice that seeps from a fruit, which is also prohibited on a holiday? After all, the Gemara observes, “an egg is enclosed” inside the hen before it is laid, while “juice is enclosed” inside the fruit before it is squeezed. But Abaye objects to this analogy for the same reason: The prohibition on drinking juice that seeped out on a holiday was not issued because the juice itself is prohibited, but rather in order to discourage people from squeezing fruit to get the juice. Throughout this discussion, much of the detail is devoted to figuring out exactly which Tanna would have held which position, and how you can tell, which often requires teasing out the implications of other rulings on very different subjects.Eventually the Gemara turns to consider a more far-reaching question. In Talmudic times, as today, Jewish communities in the Diaspora observe the festivals for two days, rather than the biblically commanded one. The reason for this is explained in the course of a further refinement of the egg debate. While the Temple stood, the Jewish calendar, which is based on lunar cycles, was established by observations of the moon in the Temple itself. When the new moon was officially sighted, this news had to be conveyed to Jewish communities outside the Jerusalem area.Jewish law is immune to the vagaries of history: The law is the law, and it can be changed only by due process.Originally, the Talmud says, this was accomplished nearly instantaneously, by means of a relay of signal torches. But at some point the Kutim—the Hebrew term for the schismatic Jewish sect we call Samaritans—began to interfere with the torches, intentionally lighting them at what the Temple authorities considered the wrong times. So, the Temple had to switch to a messenger system, dispatching people to outlying areas with news of the new moon. Because a messenger couldn’t get to everyone before the new month began, Diaspora communities were ordered to start observing holidays for two days, to make sure that at least one of them would be calendrically correct.At a later period, the sages began to calculate the calendar in advance, using astronomical observations, and the two-day rule became functionally unnecessary, since it was now easy for even distant Jewish communities to figure out when the holiday was supposed to fall. But the two-day practice was kept in force as a safeguard. “Be careful to observe the custom of your fathers that you have received,” the rabbis warned, since a time may again come when Torah study will be prohibited by the gentile authorities, and uncertainty about the calendar would arise once more. This precaution speaks volumes about both the rabbis’ reverence for tradition and their dark view of the conditions of Jewish life.This account of the origins of the two-day holiday, given on Beitzah 4b, raises a natural question. Are both days of the holiday actually holy, or is only the first day the “real” holiday, and the second merely a rabbinic reminder? Once again, the egg problem emerges as a test case. Say that an egg is laid on the first day of the holiday and is “set aside.” Can’t it then be eaten on the second day, since the second day is not subject to the same Torah prohibitions as the first? Or do we extend the prohibition to both days, treating them as equally sacred even though one is a kind of legal fiction?There is extensive disagreement about this, in the course of which the Gemara declares a fundamental principle of Jewish jurisprudence: “Any matter that was established by a vote requires another vote to permit it.” That is, if an authoritative Jewish court or Sanhedrin made a law, it can be repealed only by another such court, even if circumstances change in such a way as to render the law moot—for instance, the destruction of the Temple. In this way, the rabbis render Jewish law immune to the vagaries of history: The law is the law, and it can be changed only by due process, whether it is practicable at this moment on earth or not. Torah becomes its own virtual world, superior to the real world, in which the Jewish people are enclosed and preserved—and the Talmud itself becomes the key to the Jews’ unlikely survival.***Adam Kirsch’s Daf Yomi will return April 29, after a two-week publishing hiatus for Passover. To read Tablet’s complete archive of Daf Yomi Talmud study, click here.Adam Kirsch is a poet and literary critic, whose books include The People and the Books: 18 Classics of Jewish Literature.