Gold and silver used to have value because our currencies were based on it. This prevented governments from printing money to inflate themselves out of debt. That is, a government with a fiat currency can devalue their own currency to also devalue the real value of their debt -- debt which is conveniently denominated in their own currency.

Commodity based currencies prevented this sort of shenanigans because of the non-zero cost of adding to the money supply (the cost of mining gold and silver is much much greater than the cost of adding a few billion dollars to a government accounting ledger).

So it seems to me the value of gold is at least in part tied to the sense that governments will need some part of their money supply to be commodity based, and at least in part to the sense that fiat currencies will eventually fail.

Can someone clearly explain the positive argument for going off the gold standard?