Well, I don't know about Christianity in general, but Catholicism is certainly wide open to underground polytheism: hence Santeria and voodoo, both underground ways of worshipping Yoruba deities by disguising them as saints. Some Mayan-descended folks in Mexico and Central America also do some interesting things with the saints. Don't know if any Inca-descended Peruvian Indians do, but I wouldn't be surprised.
And then of course there's the whole question of Christianity taking over large swaths of pagan custom and ritual by, for instance, timing Christmas with the winter solstice.
My vast ignorance of Muslim custom prevents me from figuring out if any of their holidays are similarly interesting, but I'd be willing to bet money that some one of them is.

Christianity worships a human being; that can be sufficiently polytheist and/or superstitious for most, and certainly for Muslims. Then there are venerative acts towards statues in the non-Protestant churches that are venerated, etc. And saints, especially the Virgin Mary in non-Protestant churches.

Of course there are sects of or from Islam, mostly originally Shiite, that pretty much attribute godhood to Ali. And certain kabbalistic Jewish traditions border on polytheism and certain veneration of saints in the eastern community.

But I was making the more narrow point on the Trinity as being a large distinction from monotheism, or a key persuasive issue in Christianity.

Hmm, the Trinity.
Perhaps you've read the Greek Myths, by Robert Graves. His idea is that the Trinity was originally the three-aspect goddess: the young maiden, the mature and powerful woman, and the old crone. This idea pops up in popular culture: see Beauty and the Beast, where, well let's just let Disney speak:

Narrator: Once upon a time, in a faraway land, a young prince lived in a shining castle. Although he had everything his heart desired, the prince was spoiled, selfish, and unkind. But then, one winter's night, an old beggar woman came to the castle and offered him a single rose in return for shelter from the bitter cold. Repulsed by her haggard appearance, the prince sneered at the gift and turned the old woman away. But she warned him not to be deceived by appearances, for beauty is found within. And when he dismissed her again, the old woman's ugliness melted away to reveal a beautiful enchantress. The prince tried to apologize, but it was too late, for she had seen that there was no love in his heart. And as punishment, she transformed him into a hideous beast and placed a powerful spell on the castle and all who lived there. Ashamed of his monstrous form, the beast concealed himself inside his castle, with a magic mirror as his only window to the outside world. The rose she had offered was truly an enchanted rose, which would bloom until his 21st year. If he could learn to love another, and earn her love in return by the time the last petal fell, then the spell would be broken. If not, he would be doomed to remain a beast for all time. As the years passed, he fell into despair and lost all hope. For who could ever learn to love a beast?

So, the goddess first appears as the old crone, and when she's disrespected, turns into her second aspect: a powerful woman at the peak of her powers who traps the unready adolescent, administering thereby the proper punishment for his atrocious manners.
Eventually, he's saved by winning the heart of the third aspect of the trinity: the young maiden.
Which brings up how the goddess Trinity wound up as male instead of female, in Christianity: the conversion occurred in Greece, where Athena, the former principal goddess, was transformed but left with one piece of her dignity intact: by springing fully formed from the head of Zeus, she became a woman who was herself not born of a woman, and therefore was more powerful than any other.
Belle, like Athena, had a father but no mother. And she quite literally saved her man's life by choosing him.
I doubt that the writer of the Koran knew the pagan antecedents of the Trinity (The Matrix, anyone?), but assuming he didn't, he had stumbled on more than he knew by objecting to it.
Whether Disney knew what they were doing, I have no idea. I'm pretty sure Keanu Reeves was clueless.

If God wrote the Koran, he knew the pagan antecedents. OTOH, the idea of the trinity as coming from various egyptian myths is around. The thing though is that it does appear to evolve as a doctrine from bits and pieces of smaller doctrines not as a uniform concept. The cultural antecedent iconography is another story.

Either way, it is really not something that is reasoned about much in Christianity, just accepted as tieing the knot of the Incarnation thing.

Now, personally, I've always wondered how Jesus=God, but not God the Father business is actually understood by practicing Christians--it seems to be one of those things people don't quite grasp even as they supposedly believe this stuff in modern age and don't get worked up about it. One exception to this generalization I'd experienced is when I was talking to a Lebanese friend about religion--especially about Arab Christians--some years ago...where he remarked "Jesus is Allah."

Struck me as particularly weird then--even though I knew Allah to be simply Arabic word for God, for all intents and purpoes, it is still too associated in my mind with the unitarian, undivided aspect of God in Islam...and, despite repeating "true God from true God" at least once every week, trinitarian aspect of God still doesn't quite jive with me. In both senses, the statement "Jesus is Allah" still sounds a little strange to say the least.

"Now, personally, I've always wondered how Jesus=God, but not God the Father business is actually understood by practicing Christians-..."

It isn't supposed to be understood. As a priest once said "I gave a lecture on the Trinity and a lady came up to me afterwards and said, 'Father, thank you, I finally understand the Trinity'. And I said 'If you did then I did a lousy job, because it's a mystery.'"

Although I am not used to hearing that culturally, Jesus is Allah makes perfect sense; becausse that phrase is not even in the new testament directly, it would not appear in an Arabic bible but son of Allah, etc. and name of the Father son and holy spirit do appear. Allah is all over the Arabic bible.

"God from God, Light from Light" etc. is Nicene Creed language. But I suppose the creed in Arabic would read only son of the father, Allah min allah, etc. (For Muslim readers, pause and say astaghfirllah, here).

So this interpretation of the Trinity is similar to how the various Hindu gods, everything in fact, are aspects of Brahman?

Which interpretation?

In Xtianity everything is not an aspect of Allah/ God, no pantheism; and the "persons" of the Trinity are said to be more than aspects of God, but not separate beings.

How?

Official answer: It's a mystery.

The focus being that no one bothers to understand it; it's the divide-by-infinity of Christian theology, one recognizes the answer is indeterminate and leaves it there.

For reference, the specific verbiage I have from my old catechism (Lutheran variant) is:

"The only true God is. . . three distinct Persons in one divine Being, or Essence. . . .

"The Father has begotten the Son from eternity; the Son is begotten of the Father from eternity; the Holy Ghost from eternity proceeds from the Father and the Son."

The degree to which "persons" are separate from "beings" is, as Mr. Hogan points out, not explicitly addressed. One must tend to presume, however, that since the Son "person" was, in the theological context, a separate sort of, err, entity (if you will) which travelled to earth and eventually hell sans Father or Holy [Ghost/Spirit], that there is a presupposed spiritual linkage which is commonly binding apart from perceived reality. The precise method or degree of the binding is unclear but suggests a fair degree of looseness, even independence, particularly when it is suggested that the Son "intercedes" to the Father on behalf of humanity. It suggest something akin to Multiple Personality Disorder.

My intuitive feel (back from the practicing days) was that the soul/body binding supposedly present in humans was different, but not entirely dissimilar. (Where is the soul located? At what point in human biology do soul and body "link up"? What is the interacting mechanism between the two? Do souls exist prior to the body? How are they created? Etc.) Frankly it seems to me either metaphysical idea is equally "mysterious" (to put it gently)--so much so that it doesn't make much sense for anyone who believes in souls to take too much issue with the "logic" of Trinity in and of itself. The Inuit who buys a air conditioner probably has little cause to make fun of his neighbor when she buys a freezer.

I didn't quite mean so much as to actually "understand" trinity as much as knowing Jesus' divinity, the whole "one in being with the Father" stuff. I wonder if you stop someone coming out of a church in U.S. and ask "is Jesus God," I'm not so sure what response you'd get....

The more social, less religious, significance of all this is that it reflects like a barometer the relative isolation of Muslims in the modern world that they've lost a sense of awareness and scholarship of what different beliefs hold.

Part of the reason may be that most Muslims know very little about Islam, beginning with the Koran. This is obviously one of the great tools of the Islamists, all of whom seem to be hafiz, or near to it. Most Muslims know only a few verses, just enough to say their prayers as quick as possible, get married and bury somebody.

But everybody knows sura Ikhlas, its theological significance and the hadith associated with it; it has to be the single most repeated verses in Islam. However prosaic it may appear, that explains the hostility that simple Muslims might feel towards the Trinity, more specifically the raising of Jesus (AS) to equal status, based as it is on a contradiction of the central theological principle of Islam, and the definition of shirk.

As far this about the Trinity:

Most importantly it is done to explain how one can be monotheist and yet hold the beliefs of incarnation and atonement

Perhaps, but typical Muslims would be baffled as to exactly why it would be necessary to be a monotheist yet still hold these beliefs. It's not that one can't, to them it's a question of why. As you no doubt know, one of the greatest difficulties that the Sufis faced was in justifying their existence - who needs mysticism when our religion is perfect? Thus the salafism point the oceans of excess created by 'innovators'. How many Xians would sit still through discourses on dhat, sifat, mithal and the like?

In any case, to Ibn el-Arabi:

Now I am called the shepherd of the desert gazelles,
Now a Christian monk,
Now a Zoroastrian.
The Beloved is Three, yet One:
Just as the three are in reality one.

People who want to make problems always find reasons, people of reason don't make problems. In this respect the Muslims are worse than the Xians.

poor ibn-ul-'Arabi keeps getting blamed with monism and polytheism, all at the same time:
his point was rather that "la ilaha il Allah" - all that is worshipped, there is only One who is worshipped in the end, none but He - and yet he keeps getting misinterpreted and misunderstood, along with his contemporary Sufis.

I say this only because I'm tired of hearing Salafi rants about Sufis being monists and polytheists - ibn'Arabi, by the way, also said that anyone who worships the Ka'aba and actually thinks it's "God's address" - or literally "the House of God" bayt-uLlah is an idol-worshipping polytheist, as the Ka'aba is just stone and wood.

I'll say also that I converted to Islam from Christianity, and found tawhid, as described by Surah İkhlas and aqidah Tahawwiyah ( http://www.sunnah.org/aqida/aqida10.htm ) - immensely appealing and know a former Catholic priest who accepted Islam on the same basis. Nonetheless, for most Christian evangelicals I know, including my family, the theme of Christianity is not the Trinity per se, but the redemption through Christ's blood-sacrifice on the Cross, which muslims can't accept, as "no bearer of burdens can bear another's burden"

Could post more on the topic, but some other time.

"...about Sufis being monists and polytheists "

Educate me, as these terms sound almost mutually contradictory. Thanks.

funny, yes, matthew;

I was translating the words from the accusations made by ibn Arabi's critics:

'monists' because of "wahdat-ul-wujud" ("Oneness or Unity of Being"),wrongly understood to mean that everything existing has only a single being and thus shares in God's Essence, whereas the more correct understanding is that all Creation is contingent being, while only God is Necessary, and that all being is "through" God...

and 'polytheists' ("mushrikun") was equally rationalized by ibn Arabi's critics (most notably ibn Taymiyya), both because the implication of the above misunderstanding was that nature and created beings shared in God's essence, and that even the stones, animals and idols shared in the Divine Essence - while ibn Arabi's point would have been that Allah is the only One to be worshipped, and that given that all Creation is contingent on him, the ignorance of those worshippers who worship other than Allah is only upon themselves...

Basically, we could also say, pantheist?

for what the accusers believe about ibn 'Arabi, possibly...

but you would strongly offend ibn 'Arabi and anyone who's actually read and studied him by that slander, as they would say nothing in the Creation is comparable to Allah, and recognizing the Divine through creation is in noway akin to claiming the creation is divine in nature.

see also:

http://www.masud.co.uk/ISLAM/nuh/default.htm
On the validity of all religions
in the thought of ibn Al-'Arabi
and Emir 'Abd al-Qadir

and on the major topic of this post
The Trinity: a Muslim Perspective, by Abdal-Hakim Murad (Doctor T.J.Winters of Cambridge University)
http://www.masud.co.uk/ISLAM/ahm/trinity.htm

The article you linked to is the same one I linked to in the entry but it gives the original source better, thanks.

I am not calling ibn Arabi a pantheist, especially as he and I have never met, but I am assuming that is a proper alternate meaning of monist?

`monist` would be one who saw the Creation as of one Essence with the Creator, with the two `mysteriously` intermingled... I think the theological word is `panentheism,` and is perhaps accurately used when describing certain Native American and indigenous people`s beliefs about the `Great Spirit` being part of a reified `Nature`... wa Allahu alim.

What I would emphasize, with the article by Sh. Nuh Keller, is that ibn `Arabi was saying something rather different, and far from asserting that all religions and all forms of worship are True with a capital T - rather, since Allah is the Truth, that Allah is the only One that is ultimately worshipped, and it`s only ignorance of this that causes people to invent intercessors and intermediaries... and may Allah clarify and lift our misunderstandings, either of language or of form, that cause us to be ignorant. and the Qur`an is the Guide and Witness for what I state, a `firm handhold` for those who believe, and a witness against those who don`t, but are nonetheless free to do so - because what kind of invitation (`daw`ah`) is it, if one isn`t free to reject it?

A propos of nothing, really, except that it’s a funny story on the subject of the Trinity…

The scene: 1995, on the way to Sergiev Posad (formerly Zagorsk), for a celebration of the Feast of the Trinity (which, I gather, is some sort of long-neglected Orthodox holiday). Having previously been warned to show respect in a place of worship by wearing long skirts, long sleeves, and possibly covering our heads, in a nod to Russia’s resurgence of religious faith after the long years of official atheism, we are somewhat surprised to find most of the actual Russian women dressed in such conservative attire as belly shirts and Spandex bike shorts, with nary a headcovering to be seen.

Undaunted, our professor decides that maybe religious faith is stronger among the elderly, and seeks out a wizened old woman in a traditional flowered shawl, in search of an explanation for what this Feast of the Trinity is all about. With that inimitable Russian hospitality to foreigners, she begins to recount…”You know, of course, don’t you? The Trinity! Jesus, Mary, and Joseph!”

as you note, the doctrine of the trinity is used to answer what it means to be monotheistic once one says jesus is god. and as you correctly point out the trinity is therefore a conclusion and not a starting point, and one that was not arrived at until the middle of the 4th century (though, frankly, its a doctrine christians started working out very quickly once the roman empire made christianity legal).

the disconnect between christian belief and the doctrine of the trinity has been widely noted in scholarly circles and has not always been true for christianity. from the 18th century forward, it has really only been those theologians influenced by hegel (e.g., karl barth or karl rahner) who have really stressed the centrality of the doctrine of the trinity (with hegel being THE great philosopher/theologian of trinity). there are of course reasons for this and one might want to point to the rise of scholasticism in the middle ages and during the reformation era, with its effects upon both protestants and catholics. scholasticism especially seemed to treat the trinity as some sort of "mystery" that christians believe because it was revealed that they should, instead of understanding it as a description of the structure of revelation itself.

one might also point out that while the word mystery has become something rather empty and an excuse to invoke when one does not understand, technically "mystery" has generally, in the christian tradition, had the meaning of that which is uncovered or revealed: the unknown being made known. hence mysticism and 'mystical theology' which is precisely the union with god.

i will also point out that christianity is a very complex reality and the way the trinity is articulated can vary across various groups. the variation between greek and latin christianity would be the most pronounced. that said, neither latins nor greeks would anathematize one another one the topic. when you get to the jehovah's witnesses or the mormons, etc., then you are getting into an area where there is extreme deviation from standard christian accounts of both the incarnation and the trinity.

i will conclude with one brief possible summary of the trinity...
the doctrine of the trinity: that god moved into finitude and took finitude as god's own.

that provides an account of all three moments (persons) father -> finitude(son) ->reclaiming it as god (holy spirit)

best wishes,
LoA.