A Koine Greek grammar states that nouns in simple apposition are semantically understood as predicate nominatives.
So, "Paul the apostle" unpacks to "Paul is the apostle" and "the apostle is Paul" and is a reciprocating proposition.
The grammarian says:
The appositive functions very much like a PN in a convertible proposition— that is, it refers to the same thing as the first noun. The difference, however, is that a PN makes an assertion about the S (an equative verb is either stated or implied); with appositives there is assumption, not assertion (no verb is in mind).
Does English work this way as well?