R. Hershel Schachter has a great devar Torah on common sense and emunat chachamim at TorahWeb.org (via Hirhurim). According to the Midrash, Korach challenged Moshe’s authority by appealing to “common sense” arguments about tzitzit and mezuzah.

Korach claimed that since all Jews have the same level of kedusha, everyone has the right to interpret the halacha as he sees fit. His argument against Moshe’s halachic position had great appeal to the masses. It was based on common sense. He got two hundred and fifty Jewish leaders to wear four-cornered garments made of techeiles and to appear before Moshe, asking whether it was necessary to tie the techeiles strings (in tzitzis) to their garments. Common sense dictated that this was not necessary. If one string dyed techeiles takes care of a garment of any other color, then if the entire garment consists of techeiles strings, no additional strings of techeiles ought to be needed.

Moshe rabbeinu, on the other hand, argued that halacha is a self-contained discipline where common sense does not always play a role. In the discipline of biology the Talmud points out that one can not always use common sense; and the same is true of physics. Each discipline is self contained, and has its own style of logic. The same is true of the halacha.

But that doesn’t mean we should leave our common sense at the door of beit midrash either.

In our religion, are we not permitted, or better yet – obligated, to ask questions when we come across a halacha that makes no sense? Isn’t that what “lernin” is all about: to make sense out of the halacha! Our Torah is a Toras emes: it corresponds to reality, and does not contradict it! Rav Chaim Volozhener would often sign off at the close of a tshuva “Kel emes nosan lanu Toras emes, u’bilti el ho’emes eineinu – the true G-d gave us a truthful Torah and we always have to try to be honest to discover the true meaning of the halacha.” If there are two ways to understand a halacha, one which makes sense and the other does not, of course we should choose the interpretation that makes sense!

Yes, indeed, emunas chachomim is a very fundamental principle in our faith: we believe Hakadosh Baruch Hu will give divine assistance to an honest and deserving talmid chochom that he should be above his personal negios in issuing a psak; he will not have an agenda. But it doesn’t mean that we should believe in nonsense. Every exaggeration is by definition not true. It does not correspond to reality. The halacha is very nuanced because the world is very complex. Most simanim in Shulchan Aruch have many se’ifim. You can not cover all the cases in one short statement. The challenge of “lernin” is to be able to formulate the halacha precisely, without any exaggeration leaning in either direction, with “sechel”.