There's more being said here than I can keep up with. My actual intention in starting the new Dawkinsian series was to respond to some criticisms that had been made about my original articles, and especially, to correct some actual errors: my comments on the TLS and Independent pieces were really only meant as a warm up. So I shall try to comment on some of what has been said, and then write about something else.
Let's start with the Holy Trinity because that's relatively straightforward.
I don't think the formula, analogy and "spiritual statement" you propose that the Man In The Pew might provide when asked about the Trinity are "clear and lucid" at all. Something isn't lucid merely because it's neatly expressed, or clear merely because it gives a feeling of having understood something. And if you say something that, on the face of it, is contradictory, then while of course you may in fact be saying something perfectly coherent and reasonable I don't think you can be held to have said something clear and lucid until you've done something to resolve the contradiction. The usual waffle about triangles, cubes, and suchlike doesn't really do very much to resolve it.
Now, actually, I suspect that the Man In The Pew typically has a reasonably coherent notion of the nature of God. He either thinks that the Father, the Son and the Spirit are parts of God, as the sides of a cube are parts of the cube, or that they are aspects or modes of operation of God, as ice and liquid water and water vapour are of H2O. The only trouble is that these reasonably coherent notions are heresies, because any time anyone's said anything comprehensible about the Trinity the Church has declared it a heresy.....
...Did Dawkins actually say that the (alleged) fact that Christians argue about non-issues is a point against the existence of God? I don't think he did. He did suggest that ridicule might be an appropriate response when people make meaningless statements with great confidence and claim that they're vitally important, and it seems to me that that's not entirely wrong even though one can distinguish reasonably well between Arius and Athanasius. I think one can make that distinction largely because Arius, unlike Athanasius, did in fact say things that make some sense. But it happens that Athanasius won, and present-day Christians do in fact commonly affirm solemnly every week that they believe that Jesus was "of one substance with the Father", and even though they can distinguish that from "not of one substance with the Father", I doubt that one in a hundred can give a genuinely coherent account of what it means for a human being, capable of making mistakes and dying and so on, to be "of one substance with the Father". (I'm not entirely sure that even one can -- i.e., it's not clear that any genuinely coherent account exists -- but I don't wish to press that point. Also: it's probably also true that not one person in a hundred, or even one in ten thousand, could give a coherent account of what it means to say that gravity results from the curvature of spacetime; it's certainly possible for something to be very difficult to make sense of but still correct.)
When we say that someone "understands" a religious doctrine we might mean either "understands what the doctrine is" or "fully understands and conceptualises the reality which that doctrine (supposedly) represents." The ability to "say what the doctrine of the trinity is" ("It means that the Father and the Son are God, but the Father is not the Son and the Son is not the Father") isn't the same as fully understanding and conceptualizing what a triune God is like. You say that you doubt if even one believer really understands the Trinity in the second sense. I agree: no-one can fully understand and conceptualize God. Duh!
If I could be hairsplitty for a moment: the question of how a finite and limited human being can at the same time be the omnipotent God isn't strictly a question about the doctrine of the Trinity, but the doctrine of the Incarnation. The Trinity is about the relationship which "God the Son" has to "God the Father" (and always has had, and would always have had even if the universe had never been created.) Once that had been sorted out to everyone's satisfaction, the Church occupied itself with many useful discussions about what exactly it meant for "God the Son" to be "incarnated", eventually settling the issue in the middle of the fifth century.
You don't need to go as far as "the curvature of space": there are lots of things which we know or believe in but can't describe in words. "The smell of coffee" is the text-book example.
I agree that if you could look into the mind of The Man in the Pew while he was saying his prayers you would see some very crude mental pictures. I am sure that you would find a lot of people who imagined a man with a white beard saying "Shazam!" and turning into a Jewish carpenter: (a Jewish carpenter with Robert Powell's features and a tea-towel on his head, obviously.) This is the Sabellian heresy, or patripassianism if you prefer. I am sure that you would find a lot of mental pictures of a big shiny man with a smaller shiny man standing next to him: pure Arianism. (If you judged Mr Jack Chick by his amusing religious cartoon strips, then he's a pure Arian.) I think that the Sophisticated Believers use equally crude mental pictures, but that they add: "I know that this is only a crude picture; it needs to be corrected against other crude pictures, and the Complicated Doctrinal Statement." But then the holiest saints and the cleverest theologians would be the first to admit that their mental pictures of God are pretty crude diagrams: at any rate, not the real thing. Charles Wesley wrote: "Our God contracted to a span; incomprehensibly made man". If you had asked him if he thought it was theologically correct that the incarnation made God smaller, he might have replied "No: and I think that most babies are larger than "a span" as well." The map is not the territory, as the fellow said.
It's a good joke to say that any time anyone says anything sensible about the Trinity, it's declared a heresy. (You will Oscar; you will.) It would be truer, I think, to say that the Church thinks that if you bang one nail on the head, you'll dislodge all the others: that it's all very well to have a mental of a big shiny man and a small shiny man (with a big shiny bird flying above them) but that once you say "That's what God is really like" they'll say "No; it's only a picture; it needs to be corrected against other pictures".
We might spend a cheerful evening wondering whether the Crude Mental Image or the Complicated Doctrine is what people "really believe"; doubtless allowing ourselves some time to ask what is meant by "really" and "believe". We might also ponder whether the Complicated Doctrine is an attempt to systematize various Mental Pictures into a formula which everyone can more or less sign up to; or whether the Mental Pictures are various attempts to visualise the Complicated Doctrine. (The answer would come out as "A bit of both.)
I expect you are going to ask what my Crude Mental Image is. That is, if I may say so, a rather personal question. I largely think in terms of Dorothy L Sayers' analogy: that God (the Father) is like The Author of the Book, rather than any particular character or object within it. But you could imagine a writer turning up as a character in his own book: Chaucer in the Canterbury Tales ; Sim in Cerebus: Grant Morrison in Animal Man; Alisdair Gray in Lanark. (Sayers doesn't specifically refer to Animal Man, I must admit.) And you could also say that the author is present in a different way on every page of the book. This works rather well, up to a point. Suppose Arthur Dent bumps into Douglas Adams in a bar, and Douglas says "I'm the one writing this story, you know." We immediately see how Douglas (the character who Arthur Dent meets) "is" Douglas (the guy in the real world sitting at an Apple Mac typing); but we don't imagine that Douglas vanished from his desk while he was writing the book. And if we said "That bit with Marvin – that was a very Douglas joke, wasn't it" we don't say "How can it have been a Douglas joke, when he was sitting in the bar with Arthur Dent." The personality that runs through the book, the character in the bar, and the person sitting at the writing desk are all Douglas; but the person at the writing desk is not sitting in the bar and the person sitting in the bar isn't present in those bits of the book he doesn't appear in. The wrinkle, as you are about to point out, is that Christians assert that the distinction between Douglas 1, Douglas 2, and Douglas 3 would have existed even if the book had never been written.
(It is interesting that when Terry Pratchett and Neil Gaiman write about supernatural entities, they slip into a kind of Trinitarian thinking. In Sandman and the Discworld books, there is a character called Death: a cute goth girl on the one hand and a grim reaper with a pale horse on the other. In both cases, Death "really" exists in place outside of space and time; but Death is also locally present in the ordinary world every time anyone dies. But at one point, Death becomes an ordinary mortal being – a girl named Didi. People carry on dying, and indeed, when Didi dies, Death comes for her. Didi doesn't live in the Dreaming, and Didi isn't present when ever anyone dies, but all three versions of Death are Death. I am sure that Gaiman, if not Pratchett, was quite aware of the theological overtones of this story when he wrote it.)
However, I don't think The Douglas Analogy is what I believe. What I believe is that "The man on the Cross is God." The Douglas Analogy, the formula that the Son is eternally begotten of the father, God from God, light from light, of one substance with the father, begotten not created, and the old tract which said that it's kinda a like a Judge who, when he had to pass sentence on his wastrel brother, handed down the heaviest fine the law allowed, and then paid it himself. But both the Incredibly Difficult Theological Formula and the Tremendously Naive Evangelistic Tract are more or less useful ways of explaining what "God on the Cross" means. A religion which said "the man on the Cross is the Archangel Michael" would be a religion of a completely different character, which is why I show Jehovah's Witnesses the door. Well, one of many reasons, actually.
Your friend Prof. Dawkins thinks that the question of whether God the Son is "of one substance with father" or merely "of a similar substance to the father" ("same substance" vs "similar substance" "homoousios" vs "homoiousios") means "very little". Now, does he mean that, since the term "essence" or "substance" is very vague, it isn't clear what the debate is about? But "substance" had a fairly clear meaning in Aristotelian philosophy. Possibly, a problem with the Creed is that it tried to use philosophical language to describe something which really needs to be thought about in "magical" terms. But it's not too hard to find out what the two sides of the Arian controversy thought that the term "substance" meant.
A naive or ignorant person might say that there is "very little difference" between describing someone as a "nigger" and describing them as a "negro" – after all, the former word is simply a facetious pronunciation of the latter. If they heard that someone lost their job, or was even prosecuted under law, for using the first word, they might perhaps describe it as "big endism". In fact, of course, the two terms while meaningless in themselves, denote a particular set of attitudes and beliefs: to use the term "nigger" is as much as to say "I am a racist." It would have been too hard to discover that a person's preference for ""homoousios" over "homoiousios"in the fourth century denoted a position within a substantive religious debate: namely "God on the Cross" or "An Archangel on the Cross".
(Pause for long digression about the way in which offensive terms are sometimes appropriated by the target group. Resume.)
Or perhaps Dawkins' point that there is simply no such thing as a substantive religious question – that, since God does not exist, one statement about him is as good as any other? But surely, Dawkins wouldn't resort to arguing "If something doesn't exist, then it is silly to discuss what it is like. God does not exist, so it is silly to discuss what God is like. Christians discuss what God is like. Therefore Christians are silly. Therefore God does not exist." Or, more simply: "God does not exist. Therefore, God does not exist."
At the weekend, I found myself discussing with a group of friends whether Sauron's capacity to shift his shape -- into a wolf or a bat -- was an example of the wider powers of the maia to cloth themselves in whatever form they wished; or whether it was unique necromantic ability of his own; and whether the limitation placed on him after the fall of Numenor -- that he could never again assume fair form -- meant that he was trapped in a single body, or whether he could assume any foul form he wished. And if he did indeed have the power to shift his shape, whether his followers of the same order could also do so – and if so, whether that meant that balrogs might have wings at one moment and none the next. You might think that such a discussion is a waste of time. One of my fan-groups appears to believe that knowledge of the works of Tolkien (and silver age comic books, apparently) automatically disqualifies me from holding valid opinions about religion. But clearly, you can have meaningful discussions about non-existent entities.
Who succeeded Michael Henchard as Mayor? What a stupid question. There's no such PLACE as Casterbridge, so how can we possibly discuss who held political office there?
I thought that Dawkins' failure to understand that a serious religious disagreement lay behind the term "consubstantial" was one example of his ignorance of theology causing him to make weak points. You said that Dawkins' could be forgiven for not understanding that doctrine of the Trinity, because it is an obscure idea that most Christians don't understand. I said that, on the contrary, most Christians understood the doctrine of the Trinity perfectly well. You said that, in fact, the mere ability to quote a formula, use an analogy, or describe a supposed spiritual experience didn't amount to understanding, and that, in fact, the doctrine of the Trinity (or the incarnation) was so obscure that probably no-one really understood it. I think that you have inadvertently slipped between "understanding what the doctrine is" and "fully understanding and conceptualizing what it means."
I agree, of course, that neither Dawkins nor the Man in the Pew "understands" the Trinity in the deeper sense. But I don't think that, in order to understand why the church split over the Arian controversy – why, indeed the Church of England does not think that Jehovah's Witnesses are Christians, and the Jehovah's Witnesses do not think that Anglicans (or, indeed, anyone else) are Christians – you need to be able to fully conceptualize what a being who is both three and one; or a being who is both God and Man, would be like. I think you simply need to know what the doctrine is. And Dawkins could have found that out from any standard work.
In my next epistle, I may spend some time musing out loud about why Dawkins raised the issue of "consubstantiality" to begin with. Or something equally thrilling.