This is one of those questions that comes up in debates these days, often in the slightly different form of “What is the strongest argument you think the other side has?”
I am going to be succinct here.
There are no theistic arguments that trouble me. There simply are none. And so, if anything were to deconvert me from my agnostic-atheistic position, it would not be a rational, philosophical argument. I have assessed the best ones out there, and I have found them all wanting, and they certainly do not offer the best explanation for the data.
And then there is the present offering of (historical) evidence. Essentially, it’s the Bible or Qu’ran or other holy book, since all other daily claims are comparable across religions (miracles, unexplained phenomena, Jesus in a piece of toast). These books I have studied and they do not cut the mustard. I will not to use the New Testament to prove Jesus because it is circular of problematic, involving very low epistemic standards of evidence. The Old Testament is spurious at best.
As such, it is the data, modern data here and now, that I would turn to. Evidence. I think the only thing that would deconvert me would be incontrovertible evidence. You might claim I am setting the bar too high, but my position is glaringly obvious. It was summed up well in Andy Schueler’s piece “Can we choose what we believe?” which sets out the case that we don’t just choose to believe something, like the moon is made of cheese. Rather, we assess the evidence (whether consciously or not) and set this against the claims or propositions. Whichever proposition best explains the data wins the belief switch in the mind, in simple terms. Sometimes, the propositions are too close to cal, and we remain agnostic. And yes, our brains will be victim to biases and heuristics that will be at play, and will vary the evaluations compared to the next person.
We must work hard to overcome them.
Essentially, though, my mind needs evidence. In order to change my mind, given that no new amazing philosophical evidence is likely to come about, given the amount of thinking that has been done, I would need some new data that very clearly points to there being a God. What that would look like, who knows? A cross on the moon? Perhaps? Dinner with Jesus? Maybe, although I’ve got a mate called Jesus who has a pink and white beard and likes metal music, and I doubt he is God incarnate. Very much.
We’ll see. Show me what you’ve got, God.
In the meantime (he’s been on a 2000 year holiday, so don’t expect him to reply any time soon – heck, I wrote a book of 501 questions that she has yet to answer), let me know what troubles you the most, and what would ultimately convince you.