If       (input contains a chemistry term)
then say (Are you a chemist?)

If       (input contains a medicine term)
then say (Are you a doctor?)

          if I said (Are you a chemist?)
and the person said (Yes)
               then (#user is a chemist)
            and say (That's very interesting.)
                and (#should ask for name)


if       (#user is a chemist)
then     (#(Are you a chemist?) is a bad question)

if       (#user is not a chemist)
then     (#(Are you a chemist?) is a bad question)



If input (is X Y?)
and      (X is possibly Y)
then say (Possibly)