If defining Him through experience is the “correct” way of defining Him, then it’s probably not of great importance that this renders Him unassailable through discourse, although I don’t think it does so. We have important and reasonable conversations about our experiences all the time. The vast majority of people would accept that red exists, and we would not call them irrational for doing so.

Nor is experience necessarily unshareable. It is of course of paramount importance to an experiential theory of God that everyone’s beetles have a great deal in common. The whole point of their arguments is that these are universal or near universal experiences that demonstrate the existence of God. C.S. Lewis, in particular, does a remarkably good job of “showing the beetle.” I am an atheist, but I still found his writing very lucid and had indeed shared many of his experiences and thought they were of profound importance to who I am and what I should do.

I was suggesting to James not that he should take Christians or other religious people at their words when they say it is a matter of faith. Rather, I was suggesting that doing some legwork on his part might be extremely helpful in figuring out what they are talking about. Comparing experiences may be challenging, but it is certainly not impossible nor should it be a permanent impediment to reasoned discussion.

You write, “If there’s one thing that I think the writers I’ve listed make crystal clear it’s that the arguments for God that are most compelling are experiential arguments. Just as it is much easier to understand what red is by actually seeing it, these writers would tell you that it is much easier to understand what God is by experiencing Him.”

Unless I’ve interpreted him incorrectly, I believe James’s point is that nowadays, an experiential definition of God is “the most compelling” because the advance of science has pushed conceptions of God into beetle in the box territory, where they are unassailable through discourse.

But is this what theists really want? Because if one’s conception of God is defined only by its subjective, unsharable character, theists can in theory hold widely divergent, even contradictory conceptions of God. If God is defined in the way that redness is – i.e. by the first-person, qualitative aspect of an experience – then God will suffer the same “inverted qualia” problem that redness does. That is, just as my idea of red may be experientially equivalent to your idea of yellow, my idea of God may be experientially equivalent to your idea of the taste of a ham sandwich.

I think one of the powerful implications of James’s post is that a retreat into an experiential definition of God comes with benefits as well as costs. Yes, it renders the definition immune from criticism – I have a beetle in the box, and you can never prove otherwise – but it also saps the definition of its comparability – I have no way of ever knowing if my beetle is at all like yours. So theists must ask themselves: are they content to know that all of their faithful cohort have beetles in boxes, or is it important that they all have the same (or at least similar enough) beetles? In other words, is it enough that all theists have defined God based on some experience, or would it be troubling to discover that some theists have defined God in the way that you’ve defined the taste of a ham sandwich?

First, in debates about religion, morality and politics, for some reason the principle of charity that operates in most conversations breaks down completely, likely because the mental gymnastics required to “avoid attributing irrationality, logical fallacies or falsehoods to the others’ statements, when a coherent, rational interpretation of the statements is available” is considerably more difficult than in the ordinary context where people largely agree on a set of background principles. Therefore, in order to carry on a proper conversation with someone who believes in God, either you or they has to do a tremendous amount of work to get to the point where you can get to a point where the ordinary rules of language apply. I suggest that it behooves you to do the work in advance because (1) the other person is highly unlikely to do it and (2) it is really difficult, especially to try to do on the fly. I posit that the faith impasse is really just an ultimate recognition that the rules of the ordinary language game are breaking down big time, and if you want to get past it, then you’ve got to reconstruct them first.

Second, this may be an instance of you demanding a particular (kind) of proof rather than just demanding argument. If there’s one thing that I think the writers I’ve listed make crystal clear it’s that the arguments for God that are most compelling are experiential arguments. Just as it is much easier to understand what red is by actually seeing it, these writers would tell you that it is much easier to understand what God is by experiencing Him. I don’t think you should feel entitled to non-experiential proof of God in these circumstances, so I suggest reading those writers so that you get an idea of just what kind of proof and evidence theists are actually relying on.