Originally Posted by
subrosian
Sigh.
Ok. Let's start at the beginning. You have people. People create Things. Things can be anything - goods, services, raw materials, processed goods, labor (literally "people time"). The whole exchange of goods and services is called an Economy. As technology improves, the productivity of an economy improves - it produces more things. In order to facilitate easy exchange in an economy, we create a token we call Money, which is representative of an agreed upon Value. That value is determined by the "Market" - which is a fancy way of saying "ebay". In reality, all markets are a curve, since we each value different goods differently.
Anyway - economies grow. Money itself contains a value equal to the Things it can buy (remember, the Market). So, if an economy grows, but the amount of money in circulation remains the same, then the money itself becomes worth more. This is a problem - it's called Deflation, and it's what causes major depressions. In a deflationary scenario, holding onto goods is "bad" because they lose value each day, while holding onto money is good, because money always increases in value.
In the past, rare materials such as gold (in the form of coins) were used as the money themselves. The governments issuing those coins had to continuously degrade their currencies (lowering the amount of gold, or substituting cheaper metals). This difference in face versus production values is called Seigniorage. This was necessary to maintain a constant coin value.
In modern capitalist economies where changes in purchasing power occur rapidly, it became too difficult to maintain the low "normal" levels of inflation necessary to make goods trade favorably with money. A solution to this is to use fiat currency (that is, currency whose entire value is derived by government authority) and a partial reserve system, using the interest rate as the "valve" for controlling the money supply.
Unfortunately, this system is complicated to understand mentally. Many people have the impression that fiat currencies are "worth nothing". In reality, a fiat currency is simply trading against the economy that produces it - that is, the value of a dollar is derived from the value of the goods / services being circulated within the economy that uses that particular currency. The truth is, regardless of fiat or "hard" currency, the value of a coin is always dependent on the "economy" (the goods and services we are producing as a collective) and the "market" (our willingness to purchase / value assigned to good and services).
It's not so simple as "thin air". Banks generate the money they loan from the Federal Reserve, which in turn determines the money supply (yes, literally printing money) relative to the economy.