I am going to dust off my Anthropology/Archaeology degree for this one, so please pardon the roughness and simplicity as much of my knowledge is near 10 years old and there is a lot of new research being done as we type.

Oral tradition can explain a lot of simularities between Old World religions. People have lived on the the same continent for 10s of thousands of years. As people sprouted what we define as civilization in the Middle East they developed new stories (and augmented earlier tribal stories) to explain the world and thier place in it. (Check out the stories of Gilgamesh.)

When bands of people spread out across the continent, into Europe and Asia, these stories changed gradually over time, but still kept the same basic theme. Over time, these traveling groups developed their own cultural identities and own civilizations, again using thier oral tradition to define the world around them and thier place in it. Since this is a GalCiv forum , think of our fledgling Terran colonies with low moral and no access to information from the rest of the empire, they often break off to form thier own cultural identity (Independant League in this case) or join with a more influencial power.

Now keep in mind, as people began to come into contact with one another (again), they traded goods, services oral traditions and other cultural attributes that they each found pleasing. In GalCiv we have Cultural Starbases and Trade with major and minor powers (including those former Terran colonies).

In the end, Jeudism, Islam, Christiniantiy, Hinduism and Budhism (et al.) all have some elements that are similar. Using Occam's Razor, this hypothesis makes the fewest assumptions about unknowns. (ancient astronauts, etc...) This is not to say there are no "Alien Civs" out there, we simply do not know and therefore can not use alien influence as a reasonable explanation at this point.

Of course, if aliens could move across the galaxy, why would they come here? I mean there would be dozens of stars, if not hundreds of stars nearer them that have nonsentient life that could support our type of life. This is using that infamous equation that predicts the amount of life in the universe. So, why come here?

To the aliens in the saucers of course, I do think that aliens do drive them visit earth now and again but there are lots of hoaxes and such that inflate their numbers above what there should be. We cannot do intersteller travel so we are primitive. All could change of course but we're always going to be primitive to them beacause by the time we develop such travel they will have a lot better.

Exactly, alien anthropologists studying the strange primitives. So when we do blow ourselves up, the conservationists will come in a save a few for their zoos...


~SDC~

Here is my "alternate" theory of evolution:

Some remote, intelligent, space-faring specy decide to study how life forms and evolves. They find this rock which seems to contain the basic elements they think are needed for life to evolve. They drop a few amino acids and watch what happens. What do you know, lifeforms emerge from this primordial soup, it looks like the theory was correct. Then, about 250 million years ago, somebody asks "But can life evolve from a different starting point?" Hmm only one way to find out, let's push a big rock and start over with a clean slate (well almost clean). Interesting, some of the older lifeforms hang on and even become dominant, but new one forms. What are those warm-blooded furry creatures? Hmm, I wonder if they could become dominant given the opportunity. Let's throw another rock and see what happens. Ah, even more interesting, they seem to develop primitive intellect. What? No they won't be dangerous to us, at least as long as they can't leave the orbit of their star. What about the probe? It's nothing really, just a lucky shot, they are not even close to leaving their star. Besides, we still have plenty of rocks to throw.

~SDC~

Aliens here to study humour..

And as soon as we discover why they are here, then all humour will disappear.
Now what was I saying...