Non veni pacem mittere, sed gladium.
Not backed by silver or gold - not even the promise of a kiss on the cheek. "Federal Reserve Note"
It only has value because we say it does, and because you can pay your taxes with it. Real money is gold or silver - or Bitcoin!
Or buy a barrel of oil with it. Actually, gold and silver are just rocks. They too have value because we say they do. Same with Bitcoin. It's all a form of barter by proxy.