Question: Why by pikuach nefesh, saving someone’s life who might be in danger, let’s say on Shabbos, we are not concerned for the majority and if for example a building collapsed and most people inside are gentiles but there might be a Jew there we are allowed to search for him on Shabbos but when it comes to dinei nefashos, judging life and death circumstances we do rely on the majority to help with two witnesses in order to sentence someone to death, but isn’t this a case of pikuach nefesh also for if one must save a person at all costs one definitely can’t kill someone? (Kovetz Shiurim Bava Basra 225)
A. The mitzvah to save a Jew’s life even at the expense of transgressing mitzvos is based on verse of “vichai bahem” that the mitzvos are to live by not die by. The mitzvah to sentence one to death if he transgressed a sin of that severity is “uviarta hara mikirbecha” you shall wipe out the evil from amongst you.
B. By pikuach nefesh there are two factors, the mitzvah of saving a life, and the mitzvah being transgressed. By dinei nefashos there are two factors: the mitzvah of eliminating evil and the mitzvah of saving a Jew’s life.
C. In both cases where is the source of the doubt in question and which one is the after effect that just has to be taken into consideration?
Answer: In terms of saving one’s life the source of the question is whether there is a mitzvah now to save one’s life and the byproduct is desecrating Shabbos so the verse of “you shall live by them” resolves the main question at hand and says Shabbos should be transgressed even if there is a small possibility that it’s saving a Jew, just like if one definitely knows he is saving a Jew. But by laws that concern capital punishment where the question is whether to blot out evil or not then if the majority resolves that question then which is the main question at hand then there is no doubt of needing to save a life since that’s just a byproduct of what the real issue is that is wiping out evil, which the majority poskined can be done so the minority issue of saving a life doesn’t exist anymore.