Building and Destroying: Vessels (II)

The mishna (Shabbos 146a) says that it is permitted to break a barrel to take food from it on shabbos, as long as one does not intend to “make a vessel”  (i.e. to make a neat opening).  This seems to be a simple law, but it is clear from the gemara in another place (Beitza 33b) that if breaking a barrel with intent to make a vessel would be a Torah prohibition, then it would be rabbinically prohibited to break it even without such intent.  Therefore, it must be that even if one breaks it with intent to make a vessel, it is only a rabbinic prohibition.

Tosfos (שבת שם ד"ה שובר) explains that the mishna is dealing with a mustaki.  This is a barrel that is made from gluing together small pieces of pottery and is an intrinsically flimsy.  It is permissible to break a mustaki for one of two reasons.  Either it is not possible to violate a biblical prohibition of making a vessel because it is intrinsically flimsy; or, even though it is technically possible, since it is such a flimsy vessel, the Rabbis were not concerned that one would try to do it neatly, and therefore never decreed that it is prohibited.

The Ran and the Ramban learn this gemara differently.  They learn it is not possible to violate the prohibition of binyan because we are dealing with a kli, and there is no binyan b’kaylim.  Rather they hold that this case is dealing with a prohibition of maka b’patish.  This is allowed because of tzorech shabbos, that it is needed for shabbos, and is only rabbinically prohibited.

Building and Destroying: Vessels (I)

There is a dispute between Beis Hillel and Beis Shammai if yesh binyan b’kaylim or not.  This dispute is whether or not there is a prohibition to build with vessels.  Everyone agrees that we rule in accordance with Beis Hillel; however, there is a dispute among the Rishonim what exactly this means.  Rashi holds that there is no building with vessels.  Period.  No exceptions.  All of the cases that the gemara prohibits that seem to be because of binyan b’kaylim are actually prohibited because of maka b’patish, making the finishing touch to something.

The Ran and Ramban hold that there is no prohibition to build vessels.  Even so, to take various pieces and to make a vessel is prohibited.  Tosfos holds that “complete building”, i.e. making a very big change to a vessel, is considered building.

The most obvious place to see a practical difference between these opinions is with destroying a vessel.  According to Rashi it is permitted, because it has no connection to any prohibition.  There is no prohibition to undo a finishing touch.  According to the Ran and Ramban it is also permitted because the destroying is done with a vessel (that is to a vessel).  But according to Tosfos it is prohibited because it is a very significant change to a vessel.