In propositional logic, when modus ponens stands in for a syllogistic/categorical argument, with the antecedent being the conjunction of the original syllogism's premises, and the consequent the conclusion, is it the standard interpretation to regard the affirmation of the antecedent as thereby entailing the conclusion only on the assumption that the original argument was valid, i.e the validity is external to the conditional itself, as opposed to that validity somehow being transferred to the conditional so long as the antecedent-as-premises is affirmed?