Why 'quotes' work ...

I recently read an essay in which C.S. Lewis stated that 99% of all our knowledge, 99% of all the things we know comes from 'authority.'  Let me give you an example.  Have you ever been to Paris?  No?  Then how do you know it is there?  For those of you who have been to Paris, how much money do you have in the bank?  Really?  How do you know it's there?  The point is, most of what we believe or know, we know because the information comes from a trustworthy and/or experienced source.  I can't tell whether the Earth moves around the Sun, or if the Sun moves around the Earth.  I know the Earth moves around the Sun because I believe Copernicus is a reliable source of authority.

And that is why, when Mark Twain says,

"Don't go around saying the world owes you a living; the world owes you nothing.  It was here first," 

I believe it because I consider Mark Twain is a reliable, experienced and trustworthy authority.