This is one of those challenging theories. As we grow up and disregard our teaching as children we develop beliefs. Are these beliefs because of full discovery of proofs or at some point do we decide what we believe and then go about prooving it. At every point of our thoughts we decide on a belief and then go about "proving" it. It may come from our parents, our teachers, professors, or just a friend? Is there such a case where the person does extensive research and based on that decides on a position. Probably. but it may be that each point of being convinced the individual is creating proof based on a belief. One illustration is the person who submits they have the "truth" of something. I think the very best illustration of all of this is go to 10 different person(s) who profess their religion is the "truth"...??? I am a religious person but keep a positive eye as to how and why I got there?
