Talk:Formal Logic/Sentential Logic/Derivations

"That is, a derivation system is sound (has the property of soundness) if and only if every formula (and argument) derivable in its derivation system is valid (given a syntax and a semantics)."

Is this correct? I thought validity and soundness were attributes of arguments, not formulae. This also sounds more like validity than soundness. Isn't soundness the state of being valid and having actually true premises?

Even if this quote is correct, I think it should be made clearer in light of these confusions.

I'm frustrated with this book in general. It reads like a reference work, not a textbook for pedagogy.