Rosh Hashanah 13

All the measures of the sages are true.

As we have often seen, the rabbis are often preoccupied with measurement and defining precise boundaries. On today’s daf this comes into play in a discussion about how to determine which produce is grown in which year — information that is necessary for the purposes of observing the shmita (sabbatical year).

Especially in a year when land is not intentionally sewn, produce sprouts on its own schedule. Further, growth is a gradual process, much of which is invisible to the human eye. So what counts as produce grown during the shmita year? Is it produce that started growing that year? Did most of its growing during that year? Finished growing that year? Over the course of the daf, the rabbis offer a few different ways of dating produce: fruit are evaluated according to the moment of pollination; vegetables are assigned to the year in which they are picked, certain grains are linked to the moment when they took root, and wheat and grapes that grew to ⅓ of their total height by Rosh Hashanah are considered as belonging to the previous year. 

Amidst these dizzying calculations, Rav Yirmeya turns to his colleague Rabbi Zeira and says what perhaps many of us were thinking: 

And are the sages able to discern precisely between produce that reached 1/3 of its growth and produce that reached less than 1/3 of its growth? 

It appears that Rabbi Yirmeya is questioning whether one can accurately determine if a given fruit is “one-third grown” — a reasonable question, since a farmer would have to take measurements of the grain at the turn of the year and then measure the final product later to compare and determine if the plant had indeed grown to one third of its final height during shmita! It seems a fair question.

Rabbi Zeira responds, however, with a verbal thrashing so severe it suggests something else lies behind Rabbi Yirmeya’s question. 

Rabbi Zeira said to him: Do I not always tell you that you must not take yourself out of the bounds of the halakhah

Why is he so worked up? Rabbi Zeira seems to understand that Rabbi Yirmeya is questioning not the accuracy of farmers’ measurements, but something fundamental about the role of the rabbis: their very ability to set these rules, to craft the standard to begin with.

This is not the first time Rabbi Yirmeya has questioned rabbinic standard measures. In Bava Batra 23b, we learn that a fledgling bird found within 50 cubits of a dovecote can be assumed to belong to that dovecote, but at a distance of 51 cubits the dovecote owner has no claim on the bird — even if there are no other nearby dovecotes. Rav Yirmeya asks, perhaps cheekily, about a bird found with one foot within 50 cubits and one foot outside the limit.

It is not for splitting hairs but for questioning, perhaps even mocking, the whole system that Rav Yirmeya is not just rebuked, but thrown out of the beit midrash

Back on our daf, after rebuking Rabbi Yirmeya for challenging the rabbis, Rabbi Zeira reiterates his support for the rabbinic system, quoting a mishnah in Menachot (12:4) that articulates standards of measurement that are even more impossible to achieve: 

All the measures of the sages are true. One immerses himself in a mikveh containing 40 se’a of water, but in 40 se’a less a kortov (a tiny amount), he does not immerse. Similarly, an egg-bulk of impure food can render other food ritually impure, but an egg-bulk less even the volume of a sesame seed does not render food ritually impure.

Interestingly, these examples are drawn from the arena of ritual purity: ritual bath and the transference of impurity through food. Rabbi Zeira says these standards are “true.” Something real (perhaps metaphysical or invisible, but real nonetheless) changes in the world at these precise measurements: food becomes impure when it touches this amount and not that amount of impure food, a state of impurity is only removed with this exact minimal amount of water. In ritual law, the rabbinic measure creates ritual reality.

There are different kinds of measurements, some are readily visible, while others require special technology to detect, and others may rely on communal consensus and legal decisions. The case of plants growing during shmita, on our daf, is incredibly tricky because the rabbis are placing a human standard on the natural world. Rabbi Yirmeya questions whether the rabbinic algorithm for measuring growth in fact runs roughshod over the real world and our common sense ability to evaluate reality. But it’s not something the rabbis are willing to relinquish. While Rabbi Yirmeya’s question may have been dismissed today, questions about rabbinic standards will return over and over throughout the Talmud — leaving his critique of the rabbis as part of their legacy.

Read all of Rosh Hashanah 13 on Sefaria.

This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on October 22th, 2021. If you are interested in receiving the newsletter, sign up here.

Discover More

Rosh Hashanah 11

Dating historic events.

Rosh Hashanah 12

The dragon that brought on the flood.

Rosh Hashanah 20

Do our Babylonian colleagues understand the favor we did for them?