Unknown Unknowns

Found this nice saying from Donald Rumsfeld in LSST web site, highlighting our knowledge on universes.

 "As we know, there are known knowns.
   There are things we know we know.
   We also know there are known unknowns.
   That is to say we know there are
   some things we do not know.
   But there are also unknown unknowns,
   the ones we don't know we don't know."
                         

Lord Buddha said; " The subject of universe is infinite and only a Buddha can understand"
With unknown unknowns this is very true.