Very insightful post. You're very right, belief IS the single-most powerful motivator in ANYONE.
Like you said, that's why placebos work (This is medicine). It's also why:
- the 12-step AA program works (God will will save me),
- why America works (All men, including me, are created equal),
- and even why our financial system works (My money actually has tangible value).
But that's no excuse for being gullible.
Belief doesn't have to be a mysterious force we cannot control. Whether we're ruled by logic or by emotion, we can identify the EXACT reasons why we believe what we believe. The AA program and placebos work because positive thinking leads to success, America works because if we believe in it we'll work towards achieving it, and our financial system isn't working because interest is the root of all evil. There's a whole spectrum of belief, from absolute knowledge backed by scientific evidence on one end to blind faith backed by emotional zeal on the other.
It's no coincidence people like Hitler, L. Ron Hubbard of Scientology and Jim Jones of Jonestown appeal directly to people beliefs. Forget what you already believe, accept my version of the truth instead. From wikipedia, on the ritual suicide in Jonestown:
Jones made reference to the cries and screams: "I don't care how many screams you hear, I don't care how many anguished cries, death is a million times preferable to ten more days of this life. If you knew what was ahead of you -- if you knew what was ahead of you, you'd be glad to be stepping over tonight." However, survivor Odell Rhodes stated that while the poison was squirted in some children's' mouths, there was no panic or emotional outburst and people looked like they were "in a trance".
Dude, you've just scratched the surface with the "abusal of ancient words...". Take a look at ChangingMinds.org. There's a whole system of values that cause people to believe what they do. This site is all about techniques to change these beliefs.