- I was fairly  certain that    I   would   be  able    to  fly if  I   could   merely  flap    my  arms    hard    enough,
but Mary was dubious; she said I’d better flap my legs as well. - We    were    dubious about   the team’s  chance  of  success and,    as  it  turned  out,    our dubiety
(doo BYE uh tee) was justified: The team lost. 
Dubious and doubtful    don’t   mean    exactly the same    thing.  A   dubious person  is  a   person  who
has doubts. A   doubtful    outcome is  an  outcome that    isn’t   certain to  occur.
- Sam’s chances of  getting the job were    doubtful    because the employer    was dubious of
his claim that he had been president of the United States while in high school. 
Something    beyond  doubt   is  indubitable.    A   dogmatic    person  believes    his     opinions    are
indubitable.
empirical (em PIR uh kul) adj relying on experience or observation; not merely theoretical
Mnemonics:- Marco Polo    KNEW    about   the Chinese EMPIRE  because he  EXPERIENCED
it and OBSERVED it himself. - Good UMPIRES must make EMPIRICAL decisions.