If a set of theorems, or wff's, are used in conjunction with one another, does this have an impact on their completeness in terms of soundness?
For example, I have five theorems of logic, or well-formed formulas that are together an argument against dualism of the mind. If four of them act as premises for the fifth, which is used as a conclusion, would this argument using wff's be stronger or weaker if I instead used premises that were not wff's?
I understand that wff's are often used as lemmas to prove a final wff, but my question is exactly whether this method of proof is actually stronger or weaker than a formalized argument using premises which are not wff's.