There's a video clip floating around the internet in which Frank Turek is asked whether he'd continue to be a Christian if the Christian faith was proven false. Here's one link:
i) Up to a point, Turek gives a good answer. For instance, you have theological liberals who say their "Christian faith" is independent of past or future events. Their faith doesn't hinge on the Resurrection, or physical return of Christ, or historicity of the Exodus, or call of Abraham, or Noah's flood, or special creation of Adam and Eve. They treat all these accounts as parables.
Over against that dehistoricized, hallowed out Christianity, it is important to say, in a qualified sense (see below), that in principle, Christianity is falsifiable.
ii) Ironically, there are some evangelical apologists whose position differs from the theological liberals as a matter of degree rather than kind. They stake everything on the Resurrection. They are prepared to consign other biblical accounts to the status of fiction so long as they have the Resurrection.
iii) There's a certain paradox about evidence-based beliefs. On the one hand, if a professing Christian lacks articulate reasons to defend his faith, then when he encounters prima facie evidence that disproves one or more Christian essentials, he may be unable to put up an effective resistance to the challenge. That leaves his faith very fragile. An accident waiting to happen. In that regard, faith without evidence is unstable.
iv) On the other hand, evidence-based beliefs can be unstable. If the ground shifts from under what he took to be solid evidence for his faith, then that may rock his faith. If his faith is only as good as the state of the evidence, and someone challenges the evidential foundation, or marshals prima facie evidence to the contrary, then his faith may be shaken. So that would seem to make Christian faith inherently provisional.
What if someone raises an impressive sounding objection to which he has no good answer? There may be good answers, but if he doesn't know enough to know where to find them, where does that leave him? Therein lies value in the witness of the Spirit:
v) In this respect it's important to distinguish between actual evidence and prima facie evidence. It would certainly be foolish to abandon your faith just because you encounter some challenging issues. And this isn't confined to Christian philosophy. Suppose I can't prove that I'm not trapped in the Matrix. Is that a reason for me to seriously doubt the external world?
vi) It can be misleading to quote Paul's statement about how our faith is vain unless Jesus rose from the dead. Paul isn't suggesting that the Resurrection is up for grabs. Just the opposite: Paul is appealing to the fact of the Resurrection as an unquestionable standard of comparison: Given the Resurrection, if the belief or practice of Corinthians Christians is at odds with the truth of the Resurrection, then it's incumbent on them to bring their beliefs or behavior in line with the Resurrection. Paul's hypothetical is an argument ad impossibile.
vii) In addition, we can say that Christianity is falsifiable, considered in isolation. If the tomb wasn't empty on the first Easter, and you keep the rest of your belief structure intact, then you can say that falsifies Christianity. However, that artificially compartmentalizes one truth from other truths.
The question is deceptively simple. Suppose we recast it in terms of theism generally rather than Christianity in particular. If theism is proven false, would you continue to believe it? The problem is that such a question assumes that truth is independent of God's existence. But what if truth is dependent on God's existence? Then at least some version of theism would have to be true for anything else to be true. And is there a version of theism with better evidential credentials than Christianity?
viii) This goes to the question: what is truth? It goes to the question of truth-conditions and truthmakers. There are different theories of truth.
Suppose we define truth as a true proposition. But that pushes the question back a step. What are propositions? In what, if anything, do they inhere? Are propositions mental entities? Abstract objects? A physicalist rejects abstract objects.
Or suppose we define truth as a property of beliefs: a true belief. But that's a mental state. And there are problems with that definition according to the standard secular paradigm. If that's confined to human mental states, what's the standard of comparison? What makes one person's mental state true and another false?
And here's another problem: if truth is a relation between belief and a corresponding truthmaker, there are no truths unless there are minds to think them. But according to naturalistic evolution, for the first 13+ billion years of the universe, there were no minds, no brains of sufficient complexity to entertain true beliefs. But in that event, it wasn't true, at the time, that flora antedate fauna, since nothing back then was capable of entertaining that belief.
This reflects the superficiality of evidentialism. It's useful up to a point, but it needs to be undergirded by transcendental theism.