What is the origin and logic behind the perfect aspect which is used for actions started in the past and ongoing at present time or past states which is still valid at present time.
My question isn't about the progressive aspect.I am especially wondering the grammatical logic of using "been" (with the -ing form of a lexical verb) or another state verb in the past participle form to describe unfinished actions which started in the past and continue up to the present (or past situations still true).
I have been working here since 1990.
I have been here for a long time.
I have known him for five years.
I have loved her since we met.
I have wanted to go to London for all my life.