You're misunderstanding. My point is that "value" is whatever society decides it is. A piece of paper used as legal tender is just as valuable as the gold you want to "back [it] up" with because people decide that it should be so. That's all.
"In and of itself, worth nothing" doesn't mean anything. "Worth" is not an objective quality.
You're correct, but you're also missing the point.
Yes, everything's value is subjective. However, an objective value (or a price) is reached through the exchange of goods. Joe might think his private jet is worth less than a car, and he might trade away his private jets for the price of cars, but someone is going to buy and resell them at a rate that makes them a profit. You might think a Peso is worth a Dollar, but there are enough people with dollars and pesos that you won't get far trying to trade them at a 1-1 ratio, even if you're the richest man in the world.
