Another classic factor in psak that causes poskim to rely on positions they wouldn’t normally rely on is hefsed – monetary loss. Shiur and sources (including many summaries from Encyclopedia Talmudit) are available: here.
That the Torah cares about the economic stability of the Jewish people is clear. There are two formulations of this that are explicitly connected by the Yerushalmi (and many Rishonim and Achronim). Specifically, the notion of HaTorah Chasah al Mamonam shel Yisrael, the Torah had pity on the money of the Jews, and the dispensation found throughout Shas in cases of hefsed merubeh, great economic loss.
The former concept explicitly appears in Shas to explain why certain mitzvoth are patterned the way they are. For example, the Gemara explains that while the Kohen Gadol uses a golden shovel for the ketoret on Yom Kippur, during the rest of the year he uses a silver one, so as not to incur extra expenses for the Jewish people. The exact parameters of this principle are unclear. Continue reading God is Concerned about the Jews’ Money (Halachic Methodology 11, Shaat HaDechak 3)
Another example relates to a famous statement by R. Meir about the issur of Niddah.
תלמוד בבלי מסכת נדה דף לא עמוד ב
תניא, היה ר”מ אומר: מפני מה אמרה תורה נדה לשבעה – מפני שרגיל בה, וקץ בה, אמרה תורה: תהא טמאה שבעה ימים, כדי שתהא חביבה על בעלה כשעת כניסתה לחופה.
R. Meir asks why a Niddah is assurah to her husband for seven days. He answers that the Torah wanted to separate them for seven days so that when they are together again “she will be as beloved to her husband as he was she got married.” R. Meir can either be understand as explaining why there is a notion of separating for Niddah at all, or why the issur formulated as it was – as seven days with all the laws that go along with, regardless of when she stops bleeding. [Separating during menstruation was relatively common in many ancient cultures. The specific laws of Niddah are more of a chiddush than the basic notion of separation.] Either way, he offers an explanation for the laws of Niddah.
The simplest understanding is that this is homiletic/philosophical, but has no normative value. For example, there is no obligation to be a Niddah for a week every month, and if someone uses hormones to minimize how often she is a Niddah, that is fine. There is no obligation to create this distance that makes the heart grow fonder.
However, there was one Rishon (that I know of) who thought it did have (quasi-)normative value. Continue reading Homiletics or Halacha: An Example from Niddah