Schrodinger's Purim: How It Can Be Purim And Not Purim On the Same Day And Other Paradoxes in Jewish Life.

(1) The Megilla is read on the eleventh, on the twelfth, on the thirteenth, on the fourteenth, or on the fifteenth of the month of Adar, not earlier and not later. The mishna explains the circumstances when the Megilla is read on each of these days. Cities [kerakin] that have been surrounded by a wall since the days of Joshua, son of Nun, read the Megilla on the fifteenth of Adar, whereas villages and large towns that have not been walled since the days of Joshua, son of Nun, read it on the fourteenth. However, the Sages instituted that the villages may advance their reading to the day of assembly, i.e., Monday or Thursday, when the rabbinical courts are in session and the Torah is read publicly, and the villagers therefore come to the larger towns.

The Gemara asks: What is the reason for the opinion of the tanna of our mishna? The Gemara explains: It is derived through a verbal analogy between one instance of the word unwalled and another instance of the word unwalled. It is written here: “Therefore the Jews of the villages, who dwell in the unwalled towns” (Esther 9:19), and it is written there, in Moses’ statement to Joshua before the Jewish people entered Eretz Yisrael: “All these cities were fortified with high walls, gates and bars; besides unwalled towns, a great many” (Deuteronomy 3:5). Just as there, in Deuteronomy, the reference is to a city that was surrounded by a wall from the days of Joshua, son of Nun, so too here it is referring to a city that was surrounded by a wall from the days of Joshua, son of Nun.

“Places walled from the days of Joshua bin Nun read on the Fifteenth.” Rebbi Simon in the name of Rebbi Joshua ben Levi: They honored the Land of Israel which was desolate in those days and attached it to the days of Joshua bin Nun.

(1) Walled and Unwalled Cities / What Is a Walled City?

(2) As we already learned (15:4), the Sages established two separate times for celebrating Purim. Most places celebrate on the fourteenth of Adar, whereas Shushan, along with cities that were surrounded by walls at the time of Yehoshua bin Nun, celebrate on the fifteenth of Adar.

(3) It makes no difference whether the city is located in Eretz Yisrael or outside of it; any city that had a wall at the time of Yehoshua is considered a walled city, even if its wall was subsequently destroyed. Shushan, where the miracle actually took place, is the only exception; it is considered a walled city even though the city had not yet been built at the time of Yehoshua bin Nun (SA 688:1).

(4) When the Men of the Great Assembly instituted the holiday of Purim, many large cities, especially in Eretz Yisrael, had a tradition that they had been surrounded by a wall at the time of Yehoshua bin Nun. The residents of these cities, therefore, celebrated Purim on the fifteenth of Adar. Over the centuries, however, these cities have been destroyed, and the traditions regarding their status have been lost. Some modern cities, like Lod, have the same name as cities that were known to have been surrounded by a wall at the time of Yehoshua bin Nun. The problem is that we do not know with certainty whether the modern city is located exactly where the city stood in Yehoshua’s time, or perhaps it is simply named after the ancient city but is actually situated somewhere else nearby. Some ancient cities became devoid of Jews, and we do not know whether they existed at the time of Yehoshua, because the traditions regarding their status were lost. There are other cities, such as Hebron, that we know existed at the time, though we do not know if they had a wall. There is only one city concerning which there is a clear tradition that it was surrounded by a wall at the time of Yehoshua bin Nun: our holy and glorious city of Jerusalem. Jerusalem is the only place where Purim is celebrated nowadays on the fifteenth of Adar. We will first elaborate on the laws of Jerusalem and then discuss the laws of the various uncertain places.

(1) Walled and Unwalled Cities / Uncertain Places

(2) There is uncertainty about when to celebrate Purim in the following cities: Tiberias, Hebron, Shechem, Jaffa, Lod, Gaza, Tzefat, Akko, and Haifa. Some add the following cities to the list: Beit She’an, Jericho, Beersheba, Ramla. In addition, the following cities outside the Land of Israel have uncertain status: Tyre, Sidon, Damascus, Izmir, and Baghdad.

(3) The Rishonim disagree about how residents of cities of uncertain status should conduct themselves on Purim. All agree that the Megilla must be read on the fourteenth of Adar, with a berakha, in these cities, since even a resident of Jerusalem fulfills his obligation, be-di’avad, if he reads the Megilla on the fourteenth, when most of the world reads it. Therefore, in places of uncertain status, the Megilla must be read, le-khatḥila, on the fourteenth, with a berakha. The question is whether residents of these places must read it on the fifteenth as well.

(4) Some maintain that residents of uncertain places celebrate Purim exclusively on the fourteenth, with no obligation whatsoever to read the Megilla on the fifteenth. Only those who wish to follow a pious custom read it on the fifteenth without a berakha (Ramban, Rashba, Ran, Ritva).

(5) Others maintain that in places of uncertain status, the Megilla must be read on the fifteenth as well, without a berakha, so that the uncertainty surrounding these cities is not forgotten. An additional reason is to enhance the honor of Eretz Yisrael. Nevertheless, the berakha is omitted because of the uncertainty of the matter (MT, Laws of Megilla 1:11, Me’iri, Shibolei Ha-leket, SA 688:4). The poskim debate the matter of the other mitzvot of Purim – mishlo’aḥ manot, matanot la-evyonim, and se’uda. Some maintain that residents of uncertain cities observe these mitzvot only on the first day, which is Purim for most of the world (Pri Ḥadash). Others maintain that they must perform these mitzvot on the second day as well (Ri’az). People who live adjacent to cities of uncertain status observe Purim exclusively on the fourteenth, as only those who live adjacent to a city that reads the Megilla on the fifteenth with certainty take on its status, not those who live adjacent to a city of uncertain status. However, some authorities rule stringently, stating that even in places that are near a city of uncertain status, the Megilla should be read on the fifteenth as well.

(6) In practice, most uncertain places today rely on the lenient opinion and celebrate Purim exclusively on the fourteenth. Only in places where the likelihood that it was truly a walled city is greater, like in Tiberias and Hebron, do many people customarily read the Megilla on the fifteenth as well. Some even fulfill Purim’s other mitzvot on the fifteenth as well in these cities.