You're right, but that's only in the past fifty years or so. It used to be that money was backed by hard assets like gold and silver, and a bank note represente

You're right, but that's only in the past fifty years or so. It used to be that money was backed by hard assets like gold and silver, and a bank note represented a claim on the asset. Now banks don't have to back their money with anything, because they can just borrow from a bigger bank if they need more cash.