Obviously as a Muslim I read articles on spiritual philosophy through that lens.
That said, I can certainly agree that the "trick" to understanding yourself spiritually is to gain the ability to step outside yourself, look back, and try to analyze yourself through a dispassionate lens.
But, THAT said, I also have to add that the "everybody knows that's the way it is" thought is not always wrong. :-), and certainly true when it comes to religious dogma. If you believe in the Semitic Creator-God (call Him Jehovah, Yawheh, Allah, whatever you will) and you believe in those source documents, then you are under obligation to believe that what is clearly stated by Him in those source documents is undeniably true.
For example, "Thou shalt not commit adultery" is pretty clear. Thus, it makes no sense to say "I am a Jew/Christian/Muslim, but I believe adultery is OK."
Of course, few things in spiritual documents are so categorically clear. :-)