Questions about what worshipers of this faith or that are truly directing their worship toward may be fuzzy, but questions of historical fact are black and white. Like: Mithraists did not believe that Mithra was born of a human virgin in a manger with shepherds and wise men all around, etc.
You never know, some Mithraist who wanted to explore his religion further could have had the desire to write a novel about a fantasy he has about Mithra being born in a manger with shepherds and wise men around him. He goes all the way to Bethlehem to make his story come true and
voila, it happens!
The main reason we think this didn't happen is that somehow his manuscripts are lost. After his story comes true he decides to celebrate and gets drunk. He falls asleep and knocks down a candle. His house burns down and he dies in the fire. His novel is never published.
Just saying!!
NO, NO, NO! Prior to Muhammad, Allah was used by Arabic-speaking Jews to mean the Jewish God, by Arabic-speaking Christians to mean the Christian God, and by hanafis (native Arabic monotheists) to mean the One and Only One God. It was always used by those who believe that there is
only a God of Everything, never by those who believed that there was one god of the moon and another god of the sun and a god of thunder and a god of this and a god of that. The meaning of the word is "THE" God as opposed to "a" god, and claims that it ever meant anything else are simply a fabrication.
The pre-Islamic Name "Allah" was for the "Creator God". There are questions as to whether this pre-Islamic God was the superior God, but it is known there were other gods (family, associates, etc.), with this Creator God. After the event of Islam, all associations with familia were vanquished, and Allah stands alone as the supreme Creator of the Universe (according to Islam).
The "moon god" reference is myth, or exageration.
When I said "probably," I was being ironic. My point was that even if you could prove that there was a god named "Allah" prior to the advent of Islam, its meaning changed when Islam came along. But people should not miss the real motivation for such an argument. It's to give people a reason to dismiss Islam altogether as a valid religion. A whole religion is thrown in the bin just because the name of its God is associated with another god just before its introduction. I would not want that kind of tactic used on Christianity.
My philosophy is that no religion or tradition has absolute validity. They all have their flaws. Some of those flaws have more to do with flawed interpretations than anything that is actually fundamental to a religion, and there is a lot of disagreement anyway on what is actually fundamental to various religions. The least we can say is that some things are more "important," noble, honourable, valuable or constructive than others. Therefore nothing is absolute; it's all relative and it's all a matter of judgment.
I strongly disagree with the idea that people should just flock to a religion/tradition just because they find a flaw in one of its concepts. There is something more important than the arguments that a religion makes when choosing a religion: community. People are just as important as the arguments a religion makes about its validity and its various claims. That's because religion is about people too.
A religion draws people together into a family, and when a person converts to another religion, they lose a member of that family. The second religion gains power and the first one loses power. Adherents of the first religion feel persecuted and oppressed. The question of whether the convert had a valid reason for converting depends on the relationships he had with his first "family." A conversion can either be motivated by a real need or may be based on something trivial and petty. A person who converts over trivial and petty matters commits an injustice against his original religion.
If I want to decide whether a religion is valid or not, it's never going to be black and white. There are other considerations besides whether God is one or three, whether something is idolatry or if the God of a religion shares the same name with a previous god. It's how that religion treats its people. It's the human aspect. Nothing completely validates or invalidates a religion. There's always a limit to the implications of an argument.
You may have a "good argument," but the more important question may be whether it actually helps or harms anyone. What's happening in the real world? Let's get away from theology and look at the social, political and economic situation. What does this "good argument" do to people? Does it lead to a Holocaust? You may decide that it's much better to keep this "good argument" to yourself. It may be logically sound, but if it leads to genocide or murder, you are guilty of a great sin. You have missed the mark by not considering the human aspect.
As for the name "Allah" and my prior memory of some discussion of it having to do with a pagan deity, whether it was a "moon god" or not, I can't remember what people said during that discussion. It may not have been a discussion at all but a web page presenting a particular view of the name "Allah." Whatever the case, I eventually lost interest in the idea because I always sensed there was something controversial about such an argument.
After a long time of not caring or investigating further, this thread comes up. In response to bobx's and Quahom's posts, I will say this. I decided to just have a brief look at the page in Wikipedia on the name "Allah."
The page suggests that the name Allah was "previously used by pagan Meccans" to "refer to a creator deity." It also says that "Allah" literally means "the deity," so Allah isn't just a "name" but also a "title." This is why it probably would have been used by Arabic Christians and Jews as well because it's a generic title that doesn't belong to any deity. If religions are brands, then it's not a trademark you can claim. The "name" can belong to just about any God/god regarded as "special."