Can humans have a collective illusions about something? by James Kent.
The easy answer to your question is to hold a $20 bill out to a group of people. If all the people assume that a wrinkled piece of green paper has any value at all, then you have all been fooled by a collective illusion. Money and currency is the most powerful collective illusion on the planet. There are other collective illusions, like religion, but none are as embedded into our culture as the illusory value we give to a worthless piece of green paper. You have all been fooled.