Ahhh...the gut wrenching sound of science and life colliding.
Let me explain. Newtonian physics dictate that for every action there is a reaction - for every cause there is an effect. In fact, physicists in the late 19th century were sure that within 100 years we would be able to predict the immediate future with unerring accuracy. The theory was that, the more precise the measurements, the greater the accuracy of the prediction.
But the exact opposite was proved. As measurements became more and more accurate, it was found that matter on the molecular level behaved in a determidely unpredicatble manner. In fact, you cannot ever describe with certainty exactly how a particle will behave - you can only talk about it in terms of probabilty.
And so we come to what you are addressing in your post. People, on a large scale, are easy to predict. In fact, the more we know about them, the more easily we predict how they will react.
But we encounter a problem. On a fundamental level, people are inherently unpredictable. They will surprise you when you least expect it. In fact, the more and more you get to know them, the more you are only able to talk about them in terms of how they will probably react.
People, just like particles, intract with each other. They interfere constructively and destructivly with each other. In fact, people even respond to the absence of other types of people.
So, in asnwer to your question - what shapes our beliefs? We do. In each other. And we react to form a pattern of beliefs that is consistent and reliable, complimenting each other in a way that makes a beautiful world. But are we predictable?
I don't think so...
P.S. Thanks for the post...one of the very best I have seen, well, ever.
:: I am the speaker at the dawn of the age
:: and I stand at the door to the west.
~X~