When it comes to the Talmud, there are exceptions to every rule.
Near the bottom of yesterday’s daf, we encountered the first mishnah of the third chapter of Tractate Eruvin, which describes the laws of creating an eruv hatzerot, literally “a joining of courtyards.” Until now, our discussion of eruv has centered on marking various domains with posts or beams to demarcate them for the purposes of Shabbat carrying. But here we encounter a different type of eruv, one effectuated by the mixing together of shared food to join various domains together. (The word eruv literally means “mixture.”)
The type of eruv could refer to the “joining” of Shabbat borders by using food to establish a temporary domicile outside the city limits, thus extending the distance one could walk beyond the city on Shabbat. The mixing of food is also a way to merge courtyards in order to permit carrying in an alleyway shared by two or more courtyards on Shabbat.
Whatever its purpose, the mishnah tells us that all types of food could be used for this kind of eruv, except for two: water and salt (brine). This is because brine was not considered food, which is why it was also ineligible to be brought in fulfillment of the second tithe, the ancient ritual in which a farmer brought a tenth of his produce to Jerusalem
Which all leads us to a general rule about not learning from general rules:
Rabbi Yoḥanan said: One may not learn from general statements, i.e., when a general statement is made in a mishnah using the word “all,” it is not to be understood as an all-inclusive, general statement without exceptions. This is true even in a place where it says the word “except.”
According to Rabbi Yohanan, even though our mishnah noted that “all” foods could be used “except” for salt and brine, there may be other exceptions that weren’t noted. And as we will see later on the daf, there are in fact other exceptions: mushrooms and truffles don’t qualify either.
The Gemara notes that Rabbi Yohanan must have had a different mishnah in mind when he formulated this rule, one that didn’t note any exceptions but maybe should have. He was thinking of a mishnah about women’s obligations to perform mitzvot.
That mishnah, in Tractate Kiddushin, states that women are exempt from “all” time-bound positive mitzvot. That is, women do not have to perform positive commandments (the “thou shalls” rather than the “thou shall nots”) that must be done at a specific time. And yet we know this is not the case. Women are in fact obligated to eat matzah on Passover and rejoice in a sukkah on Sukkot, to hear the megillah on Purim and light the Hanukkah candles. And they are also free from some mitzvot that are not time-sensitive, like procreation and studying Torah. This doesn’t mean that women aren’t allowed to do these things — obviously women are essential for procreation — only that they aren’t required to. Clearly, the mishnah in Kiddushin was not to be taken literally.
Other examples of generalizations with exceptions follow on today’s daf, but this one has important contemporary ramifications. Whether women are obligated in mitzvot or not has become a central issue as women have sought expanded roles in Jewish life in modern times. So it’s important to remember that general rules only get you so far. There are always exceptions. And knowing what they are — and, perhaps, what they ought to be — is important to engaging with Judaism as a living and evolving tradition.