The current system of economics was invented by Issac Newton. He based the value of everything against the price of gold which was constant. Nowdays we still use the same system. Except today the price of gold fluctuates, not by much, but it still does and Newtons system was based upon the price of gold remaining constant. The economy nowdays though more uses oil as it's "yard stick". Which, unless you have been living under a rock, you should know fluctuates a great deal more than gold (relative).
Interesting no?
I realize there is a lot more to the economy than I've written here but this is still very interesting.