Whether or not I know what it means to walk is one question. Whether I need to know what it means to walk is a different question. You are fairly good at diversion, but not good at answering. Try answering the question, please without diverting it to something else. "Derivation" is not a primitive, since I can define it.
How do you define "derivation"?
The meaning of a proposition is just it` s truth value. That is, to ask about meaning is about semantics, or, the question of "what is true?". Why is this related to derivability, or fornal rules?
You said you want to know(justified true belief). In this case, derivability is not true. Derivability is a normative notion. You just do it, because it is good to do it. Just like it is good to not get piss off so easily.:sarcastic: