In practice, most observant Jews follow the lenient position and carry in cities, relying on an eruv of the tzurat ha-petaĥ type. This leads to an interesting question: given that half of the poskim are stringent, believing that an eruv of the tzurat ha–petaĥ type is not sufficient in cities with streets wider than sixteen amot (and that it is irrelevant how many people pass through), how is it that most observant Jews follow the lenient position? After all, it is a case of doubt pertaining to a Torah law, where we are normally stringent.
The simple answer is that in rare cases, when dealing with an issue in which it is very difficult to be stringent, sometimes the custom takes hold to rely on a lenient opinion even though there is a possible Torah violation at stake. Furthermore, it truly is difficult to follow the stringent position here, as that would mean that no one could go out on Shabbat with anything in his pockets, even tissues and the like, which are sometimes necessary. Additionally, families would not be able to visit one another, because one may not push a stroller in a reshut ha-rabim, and there would be no way to bring diapers, bottles, and so on. Since there is no alternative, and given that half of the poskim are lenient, we can rely on the lenient position in this case.
We should add that the poskim are not really evenly divided in this case. As we will see, some poskim ruled that there are additional requirements that must be met in order for an area to be considered a reshut ha-rabim by Torah law. If we take these requirements into account, it turns out that according to most poskim, today’s streets would not qualify as a reshut ha-rabim. Therefore, an eruv of the tzurat ha-petaĥ type is sufficient. First, according to some poskim, an area is considered a reshut ha-rabim by Torah law only when the street bisects the entire city in a straight line. If it is slightly crooked, it is no longer a reshut ha-rabim. Most cities do not have a main street that is completely straight, and thus we may rely on an eruv of the tzurat ha-petaĥ type. Second, some poskim feel that since our streets are laid out such that every street is intersected by another street, all the streets are considered enclosed by a wall on three sides. Accordingly, they do not qualify as a reshut ha-rabim by Torah law, and an eruv of the tzurat ha-petaĥ type is sufficient (AHS and Ĥazon Ish). There are additional reasons to be lenient, as explained in the notes.
When we combine all these opinions, it turns out that according to the majority of poskim, today’s streets are considered a karmelit, and carrying in them can be permitted with an eruv of the tzurat ha-petaĥ type.
Nevertheless, according to many, since a Torah prohibition may be at stake, le-khatĥila it is proper not to rely on an eruv of the tzurat ha-petaĥ type in a place where there are streets wider than sixteen amot.
. There are four, maybe five reasons that our streets are not considered reshut ha-rabim by Torah law.1) As we have seen, according to half the poskim, if 600,000 people do not traverse an area daily, it is not a public domain. Very few places meet this condition. Even though some maintain that even a street that occasionally has that many passersby is considered a reshut ha-rabim (AHS 345:26; Beit Ephraim, OĤ 26; Hilkhot Eruvin, p. 25 based on the Rishonim’s expression “600,000 found there”), such a street is uncommon as well.
2) According to Rashi and others, a street is only considered a reshut ha-rabim if it bisects the city in an absolutely straight line. Generally, this is not the case. (However, Igrot Moshe, OĤ 1:148 rejects this reasoning.)
3) Some (Beit Ephraim, OĤ 26; AHS 345:19-22; Ĥazon Ish, OĤ 107:5-8) state that given the way our streets are laid out, where each street is intersected by another street, all the streets can be considered enclosed by a wall on three sides. For according to Torah law, a wall only needs to be mostly closed. Since buildings line most streets, closing off most of the area, a street is already enclosed by two walls. Since another street intersects it, and this second street also has buildings that are close enough together to be considered a wall, the intersecting street provides the third wall. It turns out that every city street is enclosed by three walls, and thus by Torah law is not deemed a reshut ha-rabim. It is only rabbinically that an enclosure requires four walls and that a wall must be completely closed. Since this is a doubt about a rabbinic law, we can be lenient.
4) One can present a reasonable argument that it is the Sages who decided that an eruv of the tzurat ha-petaĥ type is not sufficient to permit carrying in a reshut ha-rabim; by the original Torah law, a tzurat ha-petaĥ is considered a true wall. Thus the entire debate is on the rabbinic level, and when there is a doubt about a rabbinic rule, we are lenient. (BHL presents this in 364:2 as the opinion of Rambam. Even though difficulties have been raised with it, Or Le-Tziyon 1:30 suggests that Rosh as well maintains that a tzurat ha-petaĥ is considered a wall by Torah law, in which case the debate is on the rabbinic level.)
5) Perhaps we may also say that since part of the State of Israel is surrounded by walls on three sides (albeit very distant ones), according to Tosafot they are considered legitimate walls by Torah law, so once again we are faced with a doubt about a rabbinic law (see Harĥavot 29:4:3).
Thus we see that the poskim are not truly evenly divided in this case. Rather, according to most poskim, our streets are not defined as a reshut ha-rabim by Torah law. Additionally, it is a sfek sfeika (in fact, there are four uncertainties). According to the rules of halakhic jurisprudence, in such a case the law follows the lenient position.
Some big cities contain streets where 600,000 people indeed pass through every day – not by foot but by car or bus. At first glance, it would seem that carrying in such cities cannot be permitted with an eruv of the tzurat ha-petaĥ type. Nevertheless, it seems reasonable to suggest that these intracity highways are not considered reshut ha-rabim. For since they are closed to pedestrians, they are not really open to the public. Besides, each car is considered a reshut ha-yaĥid (Yeshu’ot Malko, OĤ 26). Following this reasoning, all would agree that most streets today are not public domains according to Torah law, because once we disqualify the part of a street used by cars, the street is no longer sixteen amot wide. Some disagree with this approach (AHS 345:26; Igrot Moshe, OĤ 1:139).
Other objections have been raised to our eruvin. First, if a city contains non-Jews or Jews who desecrate Shabbat, the Sages decreed that they cannot be included in the halakhic partnership on which an eruv is based, and thus it cannot work. See below 29:7 for solutions to this problem. Second, there are often large gardens in cities, larger than beit satayim (see n. 1). These areas disqualify the eruv because they are not designed for walking in. However, in practice, if one may walk in these gardens and there are paths running through them, they do not disqualify the eruv. If the gardens are enclosed by a fence, they also do not disqualify the eruv. Third, Rambam maintains that an eruv of the tzurat ha-petaĥ type is not effective if the distance between the poles is greater than ten amot (4.56 m). However, since most poskim disagree with him, and the law is rabbinic, we do not take his position into account. (This is according to the anonymous position cited in SA 362:10.)
Even in an area enclosed by an eruv, some people try to avoid relying on it. For example, when they need to bring a baby or anything else from one house to another via the street, they walk nonstop until they reach their destination. Since there is no hanaĥa in the reshut ha-rabim, according to many this is not considered carrying by Torah law (as explained in n. 3). Doing this adds another rabbinic element to the equation, and it seems that one may thus be lenient even le-khatĥila.