So, from that moment on, we believe in what we were told.
It's a bit stupid, isn't it...? 
Yes, it is completely stupid. The terms for that kind of "knowledge" is "conditioned throught" or "received intelligence." Any informaton that we accept as true without proving it to ourselves as fact is "belief." Such belief systems account for all the conflict in this world.
I offer as evidence the wars over religion (which are really at base about money) and the wars over patriotism (which are really at base about money).
All tyrants use belief systems to manipualte the masses. Bush, for example, used patriostism and hatred against Islam to involve Americans into his Mideast holocausts, all for the sake of money -- you may substitute the word "oil" for money here.