The argument from Biblical miracles

This is a brief sequel to my previous post:

http://triablogue.blogspot.com/2014/11/is-argument-from-miracles-circular.html

The question at issue is whether it's viciously circular to cite Biblical miracles to evidence Christianity. Insofar as Biblical miracles presume the veracity of the source, aren't we begging the question? 

There are different ways of responding to that objection. But let's consider this example:

The signs of a true apostle were performed among you with utmost patience, with signs and wonders and mighty works (2 Cor 12:12).

Should we believe Paul wrought miracles because he says so? Put that baldly, the appeal would be circular. But that's not the actual form of Paul's claim. 

Paul is reminding the Corinthians of the miracles he performed in their presence. So that's not reducible to circular attestation. 

Would Paul make a claim like that unless it was true? It's a highly exposed claim. For if it's false, the Corinthians would simply retort: "Au contraire!"

Notice that the credibility of Paul's claim doesn't even presume that he's honest. It only credits him with the mother-wit not to make imprudent claims that will be shot down, and instantly expose him as a fraud. 

Put another way, the credibility of the claim depends less on addresser than the addressee. A claim like that puts Paul at the mercy of the Corinthians. For if the claim is false, they'd say: "No, Paul–you did no such thing!" 

Now, even though the modern reader wasn't there to see for himself whether or not Paul performed miracles, that doesn't alter the logic of the claim. So long as this is an authentic letter, Paul's claim is compelling. If Paul wouldn't make a claim like that unless it was true–given the audience–then the fact that a modern reader is not in the position of the Corinthians is irrelevant.