Eruvin 33 and 34 שבות בין השמשות and Eruv Techumim

Our Masechta is starting to move deep into the detailed laws of עירוב תחומין, another type of Eruv that we have not focused on much till now.

In addition to the forbidden melacha of transporting things from one domain to another, there are also limitations on where a person himself may walk on Shabbos.

Though there is no prohibition on walking from one domain to another, there is a prohibition of walking outside one’s תחום של שבת, one’s shabbos domain.

This domain is measured 2000 amos (around or a little less than a km) from the place where one is or intends to base oneself for shabbos, as at nightfall before shabbos.

By default, it is measured from one’s own house, or if in a halachically defined city or enclosed private property, from the halachik boundaries of that city or private domain.

There is a debate on the next daf (Eruvin 35) as to whether the law of תחומין is biblical or rabbinical, but the 2000 Amah domain is very stringent, to the point that if someone leaves this area on shabbos, he might have to stay put within his own 4 amos for the rest of the shabbos!

Clearly, this has a major impact on people who wish to walk from one village to another on shabbos, sometimes even from one suburb to another, if the suburbs have significant open space between them (about 139 amos, which is not very much.)

In suburban neighborhoods with large open yards, this could even affect walking from one house to another, as each house might make up its own תחום!

This also applies to going for nature walks or hikes outside fenced resorts, or even within unfenced resorts.

To address this problem, Chazal allowed one who intends in advance to travel more than 2000 amos but less than 4000 amos from his shabbos base, to make an ערוב תחומין before shabbos.

By placing some food just under 2000 amos away from his base and intending to make that place his symbolic shabbos base, he would be permitted to go anywhere with a 2000 amah radius of where he put his food, rather than from his house.

The disadvantage of doing this, is that his house will now be on or at least closer to the boundaries of his new shabbos domain in the other direction, limiting his walking over the same shabbos in that direction- as such, his shabbos movements need to be planned very carefully.

One of the requirements for the food used for the Eruv is that the food has to be accessible from the place that one makes one’s new symbolic shabbos base.

The Mishna on 32b tells us that If one places one’s Eruv food on top of a tree, this might thus present a problem.

If one’s intended shabbos base is at the bottom of the tree, but the Eruv is more than 10 handbreadths high, and more than 4 handbreadths wide, the part of the tree above 10 handbreadths might form its own private domain.

This means that carrying his Eruv from the top to the bottom, assuming the tree is in a public domain, would be forbidden, and the Eruv would thus be invalid.

The mishna rules that if the Eruv is below 10 handbreadths, the Eruv is valid.

This seems to be despite the fact that an area between 3 and 10 handbreadths above a public domain might be considered a כרמלית (neither a private or public domain) and carrying the Eruv from there to one’s shabbos base at the bottom would thus be rabbinically forbidden.

In addition, there is a rabbinical prohibition against making use of a tree on shabbos, which extends to removing something from it.

As such, regardless of where it has been placed, it should be forbidden to remove it, and the Eruv should be invalid.

The Gemara solves the later problem (and according to Rashi, by implication the former too) by explaining that the validity of the Eruv is based on whether it may be carried to one’s shabbos base during the period of בית השמשות on shabbos eve.

Although its precise time and definition is also subject to much debate, this is generally viewed as the time between שקיעה (sunset) and צאת הכוכבים (the time the stars come out), and is also referred to as ספק חשכה ספק אינה חשיכה , a time when there is a doubt whether it is considered night yet or not.

This means that during this time, it is a doubt whether it is shabbos yet or not.

When it comes to biblical law, it goes without saying that one has to treat this time as if it is shabbos, due to the rule of ספק דאורייתא לחומרא .

Yet when it comes to rabbinical law, it is possible that Chazal followed the general rule of ספק דרבנן לקולא and did not treat that time as shabbos, thus making performing rabbinically prohibited activities (שבותים) permitted during that time.

It is also possible that seeing as Chazal were aware of the ambiguous nature of this period, but did not want to confuse us whether it is shabbos or not, they intentionally applied rabbinical prohibitions during this time as well, making it no longer a question of doubt.

The Gemara explains further that the author of our Mishna follows the view of Rebbe, who holds that Chazal did not impose their own rabbinical shabbos restrictions during this twilight period.

As such, at the crucial time of בין השמשות that determines the validity of the Eruv, the biblical prohibitions of removing something from a tree (or transferring it from a כרמלית to a רשות הרבים) does not apply, and the Eruv is valid!

On 33a, the Gemara brings an explicit Beraisa where Rebbe and the רבנן argue about an Eruv placed at a height of between 3 and 10 tefachim on a tree.

Rebbe is of the view that even though this area is a כרמלית and the Eruv may thus not be moved to the public domain at the base of the tree on shabbos itself, seeing as this rabbinical prohibition did not apply during בין השמשות, the Eruv is valid for the entire shabbos.

The Rabbis disagree, arguing that any Eruv that cannot be moved to one’s shabbos domain, is invalid- the Gemara seems to understand that while they agree that בין השמשות is the definitive time, they hold that these rabbinical prohibitions apply during בין השמשות as well.

This crucial debate is also found on 34b, regarding the same Mishna’s permission to place the eruv in a pit deeper than 10 tefachim, even though it too forms its own private domain.

The Gemara understands that this part of the mishna is referring to a case where one’s chosen shabbos base above the pit is a כרמלית , and that this once again reflects the lenient view of Rebbe that rabbinical restrictions of Shabbos do not apply בין השמשות.

It follows from all the above that according to Rebbe, though biblical prohibitions of shabbos apply from sunset on Erev shabbos, activities that are only forbidden rabbinically remain permitted until dark, which could be extremely useful for those well versed in shabbos laws (and very dangerous for those who are not.)

According to those Rabbis who disagree with him, both biblical and rabbinical prohibitions come into force the moment the sun sets on Friday. (I have assumed for purposes of this post that what we refer to today as sunset is the same as the talmudic concept of שקיעה, something which is in fact the subject of an entirely different discussion.

Given the rule that הלכה כרבי מחבריו, (the law usually follows Rebbe against his colleagues,) it seems likely that his lenient ruling here might actually be authoritative.

However, we need to examine closely at least one other major source on this subject.

This is an explicit Mishna (Shabbos 34a ) which states that during ספק חשכה ספק אינה חשיכה , the twilight period, certain actions forbidden on shabbos are forbidden, but others are permitted.

At first glance, this might seem to support the lenient view of Rebbe.

However, when examining the list, one finds some things that are only rabbinically forbidden on shabbos which one may also not do during twilight!

The list of forbidden things:

1. separating tithes from ודאי (produce that has definitely or probably not been tithed)
2. Immersing new vessels (טבילת כלים)
3. Lighting candles

Whereas lighting candles is clearly a biblical prohibition, separating tithes and immersing vessels seem to be rabbinical prohibitions, yet they are still forbidden during twilight!

The list of permitted things:

1. Separated tithes from דמאי (produce bought from an ignorant person who has probably but not definitely already separated tithes.)
2. Making an Eruv
3. Insulating hot food

The above 3 are all rabbinical requirements.

This Mishna seems to take a view between that of Rebbe and the Rabbis and permit certain rabbinically forbidden actions during twilight but forbid others.

This needs serious clarification, and there seem to be two main approaches to reconciling these Mishnayos amongst the commentators, but that is it for our daf!

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.