What is the origin of the use of the object (it) in the following sentences, and what is its purpose?
I like it here!
and
Did you like it there?
In essence, the things we are saying we like are really here (this place) and there (that place) themselves - whence the insertion of the antecedent-free pronoun?
Note: I can think of plenty of antecedents you could replace the "it" with, so that's not the answer I'm looking for.
It's called a dummy it, and according to Wikipedia it's used "when a particular verb argument (or preposition) is nonexistent (it could also be unknown, irrelevant, already understood, or otherwise not to be spoken of directly), but when a reference to the argument (a pronoun) is nevertheless syntactically required."
It’s known as ‘dummy it’. It has no antecedent and is meaningless, being used merely to provide an object where otherwise there would be none. It is also found in subject position (‘It’s raining’).
