Thinking By The Book

One of the points Rav Haym Soloveitchik makes in his classic essay, Rupture and Reconstruction, is that Jews today are more likely to practice "by the book" because of a loss of connection to tradition that we used to use as the basis of our practices.  Once upon a time people learned about keeping kosher from their parents.  Today it's from the Artscroll book.  Once upon a time a boy learned how to make kiddush by watching his father.  Today there are detailed instructions available for exactly how to hold the cup in order to active the correct sefiros, and so on.  Tell someone you do something a certain way because your parents did so and you are often expected to explain what chapter and paragraph of the Shulchan Aruch it comes from.  Much of the dynamisn and liveliness of Jewish practice is lost through this although it does provide a sense of security for people who want to be able to answer the challenge "But nu, where it is written?"
I was thinking about this when reading through Rav Yaakov Mencken's recent piece in Cross Currents.  The article starts off nicely and advertises the Mishnah Berurah Yomi program which is quite an achievement and has also produced 4 volumes of an enhanced Mishnah Berurah so far. But then he illustrated the importance of his learning with this little vignette:

Several weeks ago, I woke up very early, and found myself with time to review before going to the early Shabbos morning minyan. At the time, following Dirshu’s schedule, we were studying the laws of putting out a fire that breaks out on Shabbos. Now today, most of these laws are not relevant, because we live in more urbanized settings in which a fire will almost certainly endanger someone’s life if not put out immediately. In earlier days, it wasn’t so obvious that one should put out a fire on the Sabbath! So, among the laws with little bearing in our day, I found a note in the Musaf Dirshu (Siman 334, note 63, quoting the HaShulchan HaAruch HaRav) which points out that one is allowed to advise a non-Jew to do something on behalf of himself or another non-Jew. An unlikely situation, to be certain!

Shortly before I left the house, there was a loud roar of an engine followed by an even louder crash. The driver of a borrowed pickup truck, apparently distraught about something, had intentionally gunned the engine and rammed the vehicle into several parked cars — a block away from my house, and on the route I was to follow to get to prayers. When he came to his senses, he abandoned his (mildly) injured passenger and ran away.
I came upon the scene at the same time as a friend of mine who was also planning to go to the same minyan. My friend saw a non-Jewish neighbor emerge from his house, and told him that he ought to turn off the pickup’s engine, as it and other vehicles were leaking. And then he turned to me and said, “I wonder if I was allowed to do that.”
Can you imagine? I was able to show him “chapter and verse,” thanks to Dirshu.

Perhaps it's harsh of me to ask this but when did the halacha outlaw common sense?  You have a car leaking gas and an active car engine nearby.  A resultant explosion could have tragic results.  And you need to check a book to tell you that it's permissible to turn off the engine because it's Shabbos?  Really?
Years ago I was speaking with our local Rosh Kollel (back then we had one in our community) and he was musing about whether or not the prohibition of being kind to idolaters meant that if he was walking through a door and a gentile was behind him whether it was permissible to hold the door open for the person or should he slam it shut in their faces so as not to transgress this mitzvah?  And I couldn't think of a good response that didn't start with the words "Are you serious?"
Common sense is often a danger to some in the religious world.  It's not something quantifiable.  You can't come up with rules and guides for it.  It's just something people with a mature sense of religious priorities develop and work with.  As a result it's often derided or minimized if not outlawed.
Look at the Purim story.  Here's a tale of Mordechai and Ester acting with common sense so that they can save our ancestors from being slaughtered wholesale yet every year we are treated to midrashim that try to rationalize their actions based on the assumption that they would only ever do anything if it was written down somewhere.  Go back further into Nach and you see again lots of times that the hard rules are pushed aside when common sense dictates that they simply won't work.  Not yet satisfied?  How about all the references in the Gemara to sages who, when they couldn't get a conviction of a known convict through the standard beis din proceeding resorted to extra-judicial methods to get the job of punishment done.  not for nothing is the old saying: the fifth section of the Shulchan Aruch is Common Sense.
In general we need the words of our Sages and Poskim to guide ourselves properly through life but once in a while the right decision does not come chapter and verse from a treasure tome somewhere but from that thought process the Ribono shel Olam gave each of us the potential to use.  Perhaps if we tried using it a little more things might be better for us.