Basically, I think it comes down to scale. An individual isn't enough to drive a god's corpse to do anything noticeable. A lone loon who believes in the time-mongoose isn't going to be enough to get Akatosh to incarnate as a giant mongoose and ride that mongoose into battle. But a whole culture's worth of belief might be enough to get Akatosh to show up and punch Dagon in the face. If that lone loon got enough followers, and founded an empire, well, then we might see a lot more mongeese in Tamriel.
Well i figured that that would be true but then how is it that there is Alkosh, Alduin, Akatosh, Auri-El, and all those aspects when there is one being? Seems like the biggest beliefs would define the god then. But it seems like it is not so as I previously mentioned there are different aspects.
What I believe you are implying, inadvertently or not, is that there is a measurable number of beliefs that need to be relatively similar to create another aspect of one of the Aedra. So how many times can an Aedra split into different personalities/aspects? What happens if the 'belief bar' dips beneath that certain point? Does that aspect cease to exist even though a few people believe in it?
I see lots of problems with this theory for some reason. Mythopeia may be real in TES but the multiple aspects part throws a wrench in it for me. At least in how it was explained. Plus I am being nit-picky here as I notice people get comfortable with their theories. I get the concept of it but it seems like it does not fit well in certain areas.
I like to think of the beliefs going into molds. These molds are what the Aedra were like before they died and became spirits and impotent gods in comparison to the power they had before. People's beliefs need to be in line with these molds up to a point for an aspect to start to become defined. The specifics of the beliefs are what shape the god after it comes out of the mold.
I think of a lamp with translucent glass panels on it. The lamp itself is the mold. But the panels have different colors and use the same energy source(beliefs) to give them life. The beliefs are the panels and the colors are the small variations in beliefs between different cultures. But they are all powered by the same light source or beliefs. It is the same lantern but it casts different aspects of light from its source.
Man that anology barely even makes sense to me. Bad wording I think...
"Long, long ago, before there were any people at all; even before the gods, Tamriel was chosen as a battleground by two -- things. It is difficult to find words that fit them well. I call them the Light and the Dark. Others use different names. Good and Evil, Bird and Serpent, Order and Chaos. None of these names really apply. It suffices that they are opposites, and totally antithetical. Neither is really good or evil, as we know the words. They are immortal since they do not really live, but they do exist. Even the gods and their daedric enemies are pale reflections of the eternal conflict between them. It's as though their struggle creates energies that distort their surroundings, and those energies are so powerful that life can appear, like an eddy in a stream."- http://www.imperial-library.info/content/daggerfall-light-and-dark
Going by this it's not about the individuals or the group, but rather if their ideas align with the underlying structure of conflict in the Auribs. In the case of Mundus, a bunch of dead gods, something which I suppose makes them more malleable.
So you are saying that the gods cannot be changed dramatically from what they truly are but beliefs can only make them stray from their original selves to a range of distances? You are also saying that so long as it is in line with the cosmic forces that are in conflict they can become those beliefs?