Principles of P’sak (Klalei Hora’ah)

Question

I am a yungerman learning Gemara and halacha b’iyun with the she’ifah (goal) to, be”H, eventually serve as a posek. Recently, I came across two klalei hora’ah that are unclear to me, and if possible, I would like to ask Rav Auerbach to clarify them.

D. Halevi

Yerushalayim

Safeik Pelugta

Question

My first question is in regard to one of the klalei hora’ah cited by the Mishnah Berurah (318:2). The Mishnah Berurah explains that when there is a case of doubt involving a dispute among the poskim (safeik pelugta) concerning maaseh Shabbos—forbidding something upon which a melacha was performed on Shabbos—we permit the use of the food on Shabbos.

One example of this rule concerns the shiur at which food is considered cooked for purposes of hilchos Shabbos. Some poskim rule that the shiur is maachal ben Derusa’i (partially cooked), while others maintain that the food must be mevushal kol tzorko (fully cooked). If food had already reached the stage of maachal ben Derusai and was then later cooked further on Shabbos until it became mevushal kol tzorko, one may rely on the lower shiur and be lenient.

However, I noticed that in the case of irui—pouring hot water from a kli rishon—we do not seem to apply this rule. Irui is the subject of a dispute among the Rishonim as to whether we follow Rabbeinu Tam, who holds that it has the status of a kli rishon, or the Rashbam, who maintains that it has the status of a kli sheini. In such a case, the Mishnah Berurah (ibid., 74) rules that even in a situation of doubt, we act stringently. What is the difference?

Rav Auerbach

First of all, I want to compliment you on learning Gemara and halacha b’iyun in order to arrive at halacha lemaaseh. Both my father-in-law, Rav Yosef Shalom Elyashiv, and my father, Rav Shlomo Zalman Auerbach, emphasized that clarifying the final halacha is an integral aspect of fulfilling the mitzvah of talmud Torah. Understanding the klalei hora’ah is a significant part of achieving this.

We only apply the rule of safeik pelugta when both opinions are cited in the Shulchan Aruch or the Rama, such as in the case you mentioned (318:4). With regard to irui kli rishon on Shabbos, the Shulchan Aruch in hilchos Shabbos (318:10) cites only the opinion of Rabbeinu Tam that we treat it as a kli rishon, and therefore, we do not apply that principle.

Minhag Haposkim vs Popular Minhag

Question

My second question relates to following minhagim. Until now, when the shliach tzibbur recited Kedusha, I always said the entire nusach of Kedusha along with him. Recently, I saw that the Mishnah Berurah (125:2) and Biur Halacha (109:2) write that this practice is based on the ruling of the Taz (125:1). However, elsewhere, the Mishnah Berurah writes that the correct ruling is not to recite the entire Kedusha. Rather, the tzibbur should only recite three parts of Kedusha: 1) Kadosh, Kadosh, Kadosh, 2) Boruch Kevod Hashem Mimkomo, and 3) Yimloch Hashem. This is in accordance with the view of the Vilna Gaon and numerous other poskim (125:1).

I am confused about the final ruling of the Mishnah Berurah. Should I continue to follow the popular minhag and recite the entire nusach of Kedusha, or should I instead change and recite only the three parts of Kedusha, as the Mishnah Berurah writes is the proper practice? 

Rav Auerbach

In order to answer your question, we need to distinguish between situations in which minhagim—popular practice—contradict the ikkar halacha. In such cases, something stronger than a minhag is at stake, and we may not follow the general minhag.

However, when the question is whether to follow the popular minhag—that is, the way most people actually conduct themselves—as opposed to a practice that is not the ikkar halacha but rather a minhag haposkim, we generally follow the popular minhag.

It seems to me that reciting only part of the wording of Kedusha is merely a minhag haposkim and not the ikkar halacha. For that reason, the correct path is for you to follow the minhag ha’olam.