Well put. This article by William Vallicella presents a more serious challenge than Qureshi does…
Experiential Theology

Hi Ben. Thanks for the compliment.

Much of the argument in Vallicella’s piece was discussed here. It is clear one’s theory of reference is important when answering the question (which is why I built my piece — written for a general audience — on what one means by “same”), but Vallicella’s argument left me seriously wanting:

“A dispute between me and Ed Feser, say, about whether our mutual acquaintance Tuggy has a son no doubt presupposes, and thus entails, that there is one and the same man whom we are talking about. It would be absurd to maintain that there are two Tuggys, my Tuggy and Ed’s where mine has a son and Ed’s does not. It would be absurd for me to say, “I’m talking about the true Tuggy while you, Ed, are talking about a different Tuggy, one that doesn’t exist. You are referencing, if not worshipping, a false Tuggy.” Why is this absurd? Because we are both acquainted with the man (‘in the flesh,’ by sense-perception) and we are arguing merely over the properties of the one and the same man with whom we are both acquainted. There is simply no question but that he exists and that we are both referring to him. The dispute concerns his attributes.
But of course the situation is different with God. We are not acquainted with God: God, unlike Tuggy, is not given to the senses. Mystical intuition and revelation aside, we are thrown back upon our concepts of God. And so it may be that the dispute over whether God is triune or not is not a dispute that presupposes that there is one subject-matter, but rather a dispute over whether the Christian concept of God (which includes the sub-concept triune) is instantiated or whether the Muslim concept (which does not include the subconcept triune) is instantiated. Note that they cannot both be instantiated by the same item similarly as the concept object-directed state and the concept physical state cannot be instantiated by one and the same item such as my desiring an espresso.
The point I am making against both Beckwith and Tuggy is that it is not at all obvious which of the following views is correct:
V1: Christian and Muslim can worship the same God, even though one of them must have a false belief about God, whether it be the belief that God is unitarian or the belief that God is trinitarian.
V2: Christian and Muslim must worship different Gods precisely because they have mutually exclusive conceptions of God. So it is not that one of them has a false belief about the one God they both worship; it is rather that one of them does not worship the true God at all.”

It seems V2 leads to the implications I spelled out from option two. Vallicella’s “false Tuggy” absurdity rests on the “in the flesh” distinction, meaning, I guess, that it’s not obviously absurd because both are clearly attempting to refer to the ONE concrete Tuggy. But that is exactly the point. If one is attempting to refer to The ONE God (first cause, self existent, etc.), then V2 creates the rapid expansion of mutually exclusive Gods problem. I’ll concede it may not be as obviously absurd as the Tuggy example. Yet, I think absurd is definitely in the ballpark if the implications of V2 mean you and I (assuming you are a trinitarian Christian) are worshipping different Gods.

This is not to imply some form of religious pluralism, or that all worship to the ONE God are of equal value. Those are further questions not covered by the “same God” question.

So, again, what one means by same is vital. That’s what it seems to me, at least.