We are continuing in siman 2, where we learned that the Chayei Adam is matir performing tzad miderabanan as a davar she’eino miskavein (ie, for another purpose, but inevitably tzad occurs).
It is a machlokes achronim whether the Chayei Adam permits a davar she’eino miskavein in a case of melacha derabanan, or only in the specific melacha of tzad. The Mishnah Berurah, in siman 316:1, quotes the Chayei Adam. the Mosif Dirshu brings that Rav Nissim Karelitz understands that this heter is unique to the melacha of tzad, due to the unique aspects of tzad we discussed (shiur 666). However, the Ketzos Hashulchan disagrees. (The Ketzos Hashulchan was written by Rav Avraham Chaim Naeh, who is more known for his explanations and defense of the shiurim used by Yerushalmi Yidden that were smaller than the Chazon Ish’s shiurim.) He understands the Chayei Adam as based on the heter of psik reisha d’lo nicha lei (see explanation below). Rav Naeh writes that since it is a psik reisha d’lo nicha lei in a derabanan, it is muttar in a case of tzaar (pain or discomfort). Thus, Rav Naeh understands the Chayei Adam has three conditions to create the heter to close the window in our case: 1, the tzad is question is tzad derabanan; 2, it is a psik reisha d’lo nicha lei; 3, it is a case of tzaar.
We will explain psik reisha d’lo nicha lei. When a person drags a bench across the dirt, there is a possibility it will make a furrow in the ground. The person’s intent in moving the bench was not to make a furrow, but now that it exists, it may be beneficial and they may want to use it. Whether it was muttar or assur to drag the bench is the question is known as davar she’eino miskavein. Rav Yehuda says it is assur to have dragged the bench, and Rav Shimon holds it is muttar.
If the bench is extremely heavy, the ground is soft, or the feet of the bench are pointy, it becomes inevitable that the furrow will be created. This is assur according to both opinions because it is a psik reisha.
The next question is when the person has a negative or neutral reaction to the melacha, such as when the person had no interest in the furrow. It is a machlokes rishonim whether psik reisha applies in this situation. The Aruch holds it does not apply, and therefore it is muttar to perform a davar she’eino miskavein–even though it is a psik reisha that it will create melacha as well–because the person does not care for the melacha produced. The Aruch holds this heter applies to melacha deoraysa as well. Tosfos disagrees, and holds it is assur.
The Shulchan Aruch paskens in accordance with Tosfos. The Ketzos Hashulchan is suggesting that although we generally do not pasken in accordance with the Aruch, in a case of psik reisha derabban, and in conjunction with the fact that there is tzaar, the Chayei Adam is meikil. If so, according to the Ketzos Hashulchan, this heter can apply to other melachos as well.
Halacha lemaiseh, many poskim rely on the thought process of the Ketzos Hashulchan, so one may follow it.
Summary
There is a question whether it is muttar to perform tzad as a davar she’eino miskavein (ie, for another purpose, but inevitably tzad occurs). The Chayei Adam paskens it will only be muttar in cases of tzad miderabanan, but assur in cases of tzad mideoraysa.
There is further question whether the Chayei Adam’s heter is limited to tzad or can be applied to other melachos. Halacha lemaiseh we apply it to other melachos, but only with the conditions that the melacha in question is derabanan, it is a psik reisha d’lo nicha lei, and it is a situation of tzaar.
