The fundamental premise is false; nevertheless, in the course of polite debate and discussion we block their claim at this point and ask them to furnish proof that the Disciples are messengers of God—yet they possess no such proof. For it cannot be established that the Disciples are messengers of God unless it is first established that the Messiah is God; and their attempt to establish the Messiah’s divinity must rely either on rational demonstration or on transmitted revelation. Reason not only fails to prove it; it actually deems it impossible, and they themselves do not allege a rational proof.

At most they claim that reason shows the bare possibility of such a thing, not its actual existence—though even that is unsound. Instead, they claim its reality is affirmed by transmitted evidence, that is, by words they attribute to the prophets. They allege that those words are authentically from the prophets and that they point to the Messiah’s divinity. Their method is like anyone who argues from revelation: for the most part they discuss the soundness of the isnad (chain of transmission) without demonstrating the text’s meaning, and both premises are invalid.

Accordingly, we say to them in this setting: you cannot prove that the Messiah is God except through these books; you cannot authenticate these books unless you first show that the Disciples were infallible messengers of God; and you cannot prove that they were messengers of God unless you first prove that the Messiah is God. Thus the argument becomes a vicious circle, and a vicious circle is impossible.