I am trying to understand the first sentence of Wikipedia's page on generative grammar:
Generative grammar is a linguistic theory that regards grammar as a system of rules that generates exactly those combinations of words that form grammatical sentences in a given language.
I have read this sentence a thousand times and find it completely impenetrable. (I read: "Generative grammar is a linguistic theory that regards grammar as [tautological definition of grammar].")
Maybe I have missed the joke. But is there actually any refutable "theory" known as generative grammar? Or is "generative grammar" really more of a paradigm/an approach to analysis?
If "generative grammar" is a theory in the strict sense, what is its claim, and what might be a counterclaim?
Related:
What does "generative" mean? Can a linguistic theory be non-generative?