Eruvin 15-16 More on Eruv principles, dispute, and הלכה למשה מסיני

Our two daf contain pivotal sugyos regarding the laws of partitions and Eruvin.

One of them is a famous dispute between Abaya and Rava regarding a לחי העומד מאליו (a post that was already there prior to it being designated for use in closing off a מבוי.

The classic example is if a part of the one wall sticks out at a 90-degree angle to the wall, forming an effective post.

So long as he had in mind the day before that it should be used as a post for the Eruv, Abaya is of the view that it is acceptable.

On the other hand, Rava is of the view that seeing as it was not placed there specifically to serve as an Eruv pole, it is invalid.

After much back and forth, the Gemara brings a proof that Rav held like the lenient opinion of Abaya, which seems to be conclusive in allowing us to rule in his favor.

It is interesting that although we have a general rule that whenever Abaya and Rava disagree, we follow the ruling of Rava, the Gemara (Bava Metzia 22b ) gives an acronym יעל קגם for 6 cases where we follow Abaya, and Rashi identifies our case, לחי העומד מאליו as one of them.

We should note that at least in the case of our sugya, as well as the sugya quoted above, this is because the Gemara was able to find strong evidence in his favor.

We mentioned in our previous post that the Rambam (Mamrim 1/3) is of the view that things mentioned explicitly in the Torah or passed on orally to Moshe at Sinai are not subject to מחלוקת (debate,) and debates are only find regarding laws based on Chazal’s interpretations of the former through the rules of interpretation or rabbinical decrees and the like.

He also said (ibid 1/4) that even such debates were always settled eventually by the בית דין הגדול (great court or “Sanhedrin” of 71 ordained judges,) and once they were settled, there was no room for halachik debate.

In contrast, once the great court ceased to function, new debates remained essentially unsettled and each sage was free to follow and teach his own view to his students, who would typically follow their Rabbi- the default rule for undecided debates was to be stringent in biblical matters and lenient in rabbinical ones. (Mamrim 1/5)

In reality, this has not been the case, and in Amoraic Bavel where the much-weakened Sanhedrin back in Tiberius had little power, as well as after it ceased to function altogether, later Amoraim have come to conclusions regarding disputes which have thereafter also been regarded as binding.

There have even been rules of thumb formulated, such as following Rav over Shmuel, Rabbi Yochanan over Rav or Shmuel, and Rava over Abaya etc.

The Rambam himself (introduction to M.T.) explains the dictum of רבינא ורב אשי סוף הוראה (Bava Metzia 86a) as meaning that the later Amoraim, Ravina and Rav Ashi, who sealed the Talmud Bavli, essentially had the authority of בית דין הגדול for the last time in history, given that their rulings spread and were accepted by the Jewish people as a whole and all or most of its sages.

Although there is much to discuss and analyse here, it seems clear that a simple understanding of the earlier-quoted Rambam that makes authoritative dispute resolution entirely dependant on בית דין הגדול itself is not sufficient.

In another pivotal dispute, רב פפא, and רב הונא בריה דר’יהושע debate whether פרוץ כעומד (open area equivalent to closed area) is acceptable to consider a side as partitioned off or not.

The general rule is that when מחיצות (partitions) are used to close off a רשות היחיד, gaps of up to 10 אמות are permitted, and considered to be an acceptable פתח (opening) rather than a פירצה (gap)

However, there is an additional requirement recorded in the Mishna on 15b, that there may not be more open space than closed space (in the absence of a צורת הפתח in which case it is more complex.)

The Gemara on this Mishna opens with the above-mentioned debate regarding whether it is sufficient if the closed area is equal to the open area, or whether it needs to be MORE than the open area.

The Gemara seems to understand that the requirement that most of the partition not be open is a הלכה למשה מסיני (law given orally to Moshe at Sinai and passed on via tradition.)- (the precise term used here is “אגמריה רחמנא למשה” which seems pretty self-explanatory!)

It then understands the dispute to be a question of the nature of this הל”מ.

Was it a requirement not to allow most of the partition to be open, or was it a requirement requiring most of the partition to be closed?

Much debate follows onto daf 16 until in a major curveball, the halacha is resolved according to the lenient view, but this seems to be an explicit example of a dispute regarding something passed on explicitly to Moshe at Sinai, a counter-example to the Rambam’s hypothesis limiting such debate to matters involving the rules of interpretation or rabbinic decrees.

Once again, it seems that a simple explanation of the Rambam might not seem feasible and more analysis is required!

These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha.

Eruvin 2 Introduction, Technical measurements and clean language.

I was discussing my daf posts with my friend and colleague, Rabbi Matthew Liebenberg of Claremont Shul, Cape-Town, and he tried to warn me that keeping up the pace and variety of posts will be much more challenging when we get to Eruvin, which is known as a particularly complicated and technical masechta.

Though I could not deny that I share a degree of concern, I replied that Eruvin is actually one of my “favorite” tractates, assuming it is possible or appropriate to say such a thing. In addition to being filled with fascinating and extremely practical rules essential to understanding the practicalities of Eruv building, something almost all of us need to know, it also contains many general ideas and topics that apply to all of Torah holistically.

This combination of material typical of the Gemara can be found right here on the first daf as well.

The thrust of the first daf deals with the technical requirements for a quiet side-street or alley to be considered a private domain on Shabbos.

The typical neighborhood in the times of Chazal (as can still be seen in some older neighborhoods of Yerushalayim) consisted of a מבוי – a short and narrow side-street or alley which opened to the main public thoroughfare on 1 or 2 sides.

Various חצרות (courtyards) opened to this central מבוי and each courtyard had houses that opened to it.

מדאורייתא ( at a biblical level,) any area enclosed on 3 sides (the exact number of sides/partitions is subject to debate later) was considered a private domain, and carrying within it was permitted.

As such, as far as biblical law is concerned, it is permitted to carry from one house to another within the courtyard, from one courtyard to another within the common מבוי , or within the courtyards or מבוי , so long as the מבאי is only open on one side to the public domain.

If the מבוי is open on two sides to the public domain, it is more complex, as the מבוי itself could be considered part of it.

Our Mishna and sugya deals with a מבוי that is closed on 3 sides and only open on one side to the public domain.

We see later that there is a rabbinical requirement to symbolically mark or enclose such a מבוי with either a pole on one side, or a beam going from one side to the other (there is some debate about these precise requirements as well.)

Our Mishna focusses on the maximum height that this pole or beam may be, as well as the maximum width of the open side, and rules that if they are higher than 20 amos (arm-lengths/cubits) or wider than 10 amos respectively, they need to be lowered or narrowed.

Rabbi Yehuda disagrees and says there is no such requirement.

It is unclear from the Mishna whether Rabbi Yehuda holds that the fourth side can be of infinite height or width, or whether he too places a limit on this, but simply a higher or wider one, but it would seem that if the later is correct, one could have expected him to say what this limit is.

The Gemara notes that a similar maximum height is discussed regarding a Sukkah (Sukkah 2a,) but the language used there is different.

Whereas in our case, we are told that a מבוי that is too high needs to be lowered, regarding Sukkah, we are simply told that it is פסול (invalid.)

As in both cases, lowering it is both compulsory and effective, the difference in language needs to be explained, and the parallel sugya in sukkah asks the very same question and gives the very same answers.

Two answers are given :

  1. Seeing as the Sukkah is דאורייתא (biblical,) the Mishna uses the word “invalid.” As the pole or beam of aמבוי are only rabbinical requirements, the mishna simply tells us the תקנתיה (solution.)
  2. The later language is also appropriate in theory for the biblical requirement of Sukkah, but seeing as a Sukkah has multiple constraints, each requiring a different solution, the Mishna chooses one word that applies to all of them, for the sake of brevity. Rashi explains that this is based on the principle (Pesachim 3b) that one should always teach one’s students using concise language.

There are various approaches in the Rishonim as to how to understand the first answer.

Rashi seems to understand that when the Gemara contrasts the biblical Sukkah with the rabbinical מבוי , it is not referring to the actual requirement of dwelling in a Sukkah or putting a pole or beam on a מבוי, even though the distinction certainly applies to that as well, but to the maximum height of the Sukkah and the מבוי.

We derive the maximum height of a sukkah from a verse in the Torah: למען ידעו דורותיכם כי בסוכות הושבתי את בני ישראל (“So that your generations will know that I placed the Jewish people in sukkot” -Vayikra 23/43.)- the Sukkah has to be low enough for the roof to be noticed.

As such, this requirement predates the writing down of the mishna by far, and it is appropriate to say that it is already invalid.

In contrast, the requirement to mark a מבוי with a pole or a beam itself is only rabbinical and its maximum dimensions are also. Seeing as the Mishna is the first to teach us these maximum dimensions, it is not appropriate to label the מבוי as already invalid but only to tell us how to solve the issue from the beginning.

This explanation has various difficulties, but I shall not dwell on them in this post.

Tosfos understands the answer a little differently- Due to the strict biblical requirements of sukkah, we are concerned that using a softer language would make us think that the requirement to fix it up is only לכתחילה (in the first place,) but if one sat in the sukkah without making these corrections, one would fulfill the mitzva still בדיעבד (post-facto.)

As such, the harsher language is preferred.

In the case of Eruvin, seeing as the requirement is only rabbinical, we are less concerned that a person might make this error, and we choose to use the softer language, in keeping with the principle (Pesachim 3a) that it is always best to use לישנא מעליה (positive language ) where possible.

We see that there are 3 principles at work here, which sometimes need to be traded off against each other, and it is fascinating to note that both Rashi and Tosfos refer to the same sugya in Pesachim which discusses 2 of these principles and the trade-off between them, but for completely opposite purposes.

  1. Language needs to be נקיה (clean), and that doesn’t just mean avoiding foul language but specifically choosing לשון מעליא (positive language.)
  2. Language needs to be concise (probably to make it easier to comprehend and remember.)
  3. Language needs to be clear or strong enough to convey the historical timeline of the law (Rashi) or the stringency of the law (Tosfos)

According to the first answer in the Gemara, the third factor over-rides the first factor, and strength of message over-rides the need for positive language.

According to the second answer in the Gemara, either positive language still takes priority over strength of message, or the positive language given is still considered appropriate or strong enough to give over the importance of the message.

However, the second factor certainly takes priority over the first, and concise direct language is preferred over positive language, as is indeed the conclusion of the above-quoted sugya in Pesachim.

There is lots more to say about the requirements for language to be clean, concise, and strong enough and how they trade-off with each other, but we have certainly seen on this first daf how the Gemara is able to focus on the one hand on specific and technical rules relating to the subject at hand, and at the same time teach us multiple principles that could apply to every aspect of our lives!

These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha.