The Church says we worship the same God.
And so we do. End of story. Why is this hard?
Lumen Gentium 10 is pretty clear about the issue:
In the first place amongst these there are the Mohammedans, who, professing to hold the faith of Abraham, along with us adore the one and merciful God, who on the last day will judge mankind.
So along with Muslims, we worship the one and merciful God.
It's not difficult, people.
Of course, it is objected that the picture of God in the Quran and that of the Bible is radically different.
See, when you ask if you're talking about the same being, having radically different ideas about who that person is does not negate that you're talking about the same person.
If you ask social conservative bloggers who I am, they will have radically different things to say about me than leftists.
That does not mean they're not talking about the same person.
In the Spencer article, the question is raised in order to underline the differences between Muslims and Catholics.
And that's legitimate.
But raising the question as "Do Catholics and Muslims worship the same God" leaves open to the suggestion that we don't worship the same God. And this idea is rampant among a certain strain of otherwise Orthodox Catholics.
Saying that we do not worship the same God because we have radically different ideas about God is false. It does not conform to Catholic doctrine.
Yes we do. We may not like the fact that we do, but when the Muslims talk about God and we talk about God, we're talking about the same person. It's just that very often, Muslims are wrong about God.
Dissent from Catholic teaching is dissent from Catholic teaching, whether it's on abortion, homosexuality or the identity of God.
If we are to correctly assess Islam in all its dimensions in order to combat its errors, we must know the truth about it.