As the man said: the world is more complex than you ''can'' imagine. And when building software you'll soon have constructed a new world that's certainly more complex than you thought it was going to be.

Humans are bad at dealing with complexity. There are many tools and techniques available to assist you with this. But, your "intuition" will mislead you more times than not. InevitableIllusions discusses many examples of this. Your "common sense" view of the world (and mine) is just plain ''wrong''

Therefore, don't use your CommonSense. Use your higher faculties. 

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But mom, it's all I've got!

''I don't believe that for a second. Don't you have a degree? Learning how to think is an important skill in problem solving.'' 

Well, different people mean different things by "common sense".  On this page, the meaning seems to be, "whatever seems to make sense to you."  Certainly your mother would never tell you to abandon common sense.  And as a matter of fact, recent college graduates are often crippled by book-learning, desperately in need of regenerating their common sense.

''I agree common sense is a good way to reduce complexity, however it isn't the only means available to you. Forcing yourself to switch perspectives, ala SixThinkingHats, generates new insights and sheds light on shadows. Moreover, common sense is often wrong. You shouldn't presume that your simplification of the complex world is necessarily correct. Actually, on the fringes of your experience, your common sense is more likely to be incorrect than correct.''

We probably don't disagree.  I normally avoid the term "common sense", because of the ambiguity, but I went along with it to reply to this page and now I've gotten into trouble.  (I've added some definitions to CommonSense to get across the extent of the ambiguity.)

I don't think that as our knowledge deepens and broadens, we switch to a "higher faculty".  Rather, using the same ol' faculty by which aborigines of the Amazon ascribe human-like motivations and reasoning to their prey in order to plan their pursuit, we simply learn more stuff and generate and toss out more failed ideas.  In practice, the appeal to a "higher faculty" is an exhortation to blindly crank symbols through a machinery of rules without any sense that what you're doing makes sense.

I think this is a disease of much higher education: one learns incantations to get good grades, without getting any sense that the incantations are ''true'' or at least a good educated guess.  Using these "higher faculties" amounts to applying ideas without a ''feel'' for where or why they're applicable.  Having distorted one's cognitive style in this way, one must insist that one possesses a path to truth that the great unwashed don't have and can't appreciate.  If learning all this stuff could be done with mere CommonSense, so that a real master could explain most of the ideas in an hour or two to any 12-year-old--well, the ability to write the incantations wouldn't feel so special.

But you probably didn't mean any of this.  You probably just meant not to remain stuck with the everyday insights that adequately describe things at everyday scales, since it turns out that they don't apply so well outside of those limits.  Is that right?  If so, then we totally agree.  And certainly I agree that it's wonderfully beneficial to switch among the SixThinkingHats, and many other ways of shaking up your brain, though I wouldn't call this a rejection of common sense.  Oops, I said I was going to stop using that term.  --BenKovitz

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See also: UseYourCommonSense, CommonSense, AdviceFromNowhere