Student or Learner
In the following, ex1's a seems to denote the concept of "one of many" and so does ex2's a, but we've learned "a" means unspecific things while "the" means specific things, maybe this makes sense.
But in numerous cases of ex2 when you define something or some person, if you think "a" means an unspecific person, it is contradictory as you are also pointing at the very specific person of "He", so I'd like to know what they think in ex2 in terms of specific or "one of many".
ex1)Where can I buy a newspaper?
ex2)He is a student.