One of my favorite bond films is Goldfinger (1965), starring Sean Connery as James Bond and Gert Frobe as Auric Goldfinger. In the movie, Goldfinger hatches a plan (they always hatch a plan) to destroy the gold reserves at Fort Knox. This will make his own gold holdings much more valuable, but, Bond intones, it will also destroy the world's economy, since the gold in Fort Knox "backs" our money, and if it were to disappear, we'd have hyperinflation.
And I wondered about that a bit. Suppose a meteor filled with gold were to crash onto Federal Property, and they hook up some tractors and drag the thing into Fort Knox. Would this massive new pile of gold cause hyper-deflation?
Bottom line, I don't think money needs to be backed by anything. It just needs to be limited in its quantity. For example, if gold is money, then what is gold backed by? Anyway, Goldfinger is worth a watch -- great film.