On the Banks of the Pit

Shabbat (11:2) | Yisrael Bankier | 13 years ago

The eleventh perek discusses the prohibition of carrying on Shabbat. It began with the prohibition of carrying between a private domain and a public domain and then the prohibition of carrying four amot in the public domain. Broadly speaking the definition of a private domain (reshut hayachid) is any area that is walled off with a fence ten tephachim high and is at least four by four amot in area. The Mishnah (11:2) adds that a pit that is ten tephachim deep or a mound that is ten tephachim high is also defined as a reshut hayachid, provided it contains the above stated minimum area.

To be more precise the Mishnah taught that if the bank of the pit is ten tephachim high then one will have transgressed the prohibition if transferring an object from the public domain on to its bank. How the ten tephachim are measured and the dimensions of the pit are the subject of debate. 

The Gemara(Shabbat 99a) asks why it was necessary to teach the more complicated case of a pit in combination with its bank and not simply a case of a pit that was ten tephachim deep. The Gemara answers that this Mishnah would be supporting to position of R’ Yochanan who explains that the depth of a pit and the height of its bank can combine to make ten tephachim defining the pit as a reshut hayachid. 

According to the simple reading of the Gemara, the case in our Mishnah is where the depth and height of the pit and bank are together ten tephachim, and therefore one cannot transfer items to and from the pit from the public domain on Shabbat (see Rashi and Ritva).

The Tosfot however question the necessity of the Mishnah teaching this case. The reason is that a Mishnah in Eruvin (99b) teaches this exact same point. Consequently the Tosfot suggest that the case of our Mishnah is where the area of the pit is only four by four amot in combination with the walls. Consequently the inside of the pit is not a reshut hayachid. So what is a reshut hayachid? What is the Mishnah then trying to teach? The Tosfot explains that the bank alone is ten tephachim high. The Mishnah is teaching us that the pit it surrounds can combine with it to make its area four by four amot. This explanation fits closely with the words of the Mishnah that seems to only refer to the height of the bank and mentions a transgression when transferring to and from the bank (and not the pit). Indeed the Gemara in Eiruvin (77a) discusses the very cases and explains that since one could easily place something over the bank and find the surface usable it is defined as a reshut hayachid. 

One point that is discussed is the original case where the ten tephachim is made up of the pit and the bank and the area inside the pit is four by four amot. Would one be liable if they placed something on the bank? Is the bank considered part of the reshut hayachid?  

The Tosfot answer that only if the bank itself was ten tephachim high would one be liable. Presumably the bank is only usable to those in the public domain at that height. 

The Ritva(Shabbat 99b) however only requires the combined height and depth to be ten tephachim. In that case the bank is considered part of the reshut hayachid. This is much like how holes in a reshut hayachid share its status despite not being its space. The doubt the Ritva(Eiruvin 87b) has however is whether the bank must be at least three tephachim high. One the one hand, we know that any surface that is less than three tephachim is considered batel and part of the public domain. Consequently the bank would need to be at least three tephachim high to be considered part of the reshut hayachid. Alternatively, and it is this understanding he prefers, since the bank is constructed to serve the pit, it would not be annulled in this case even if it was less than three tephachim high. 

Download