You've made the mistake of assuming that more wealth (economic growth) requires a greater quantity of money. It doesn't. Money is just the exchange mechanism. If the amount of gold in the world stays static, but we improve our economies it would just result in prices falling.

If we could not find more gold we could still have economic growth, it's just that the value of gold would rise relative to the goods it could buy. (ie prices would fall)

You can read more here: http://www.mises.org/mmmp/mmmp5.asp

I'm by no means an expert, but a lot of mainstream economists don't seem to abide by this view. They could be wrong, of course, because mainstream doesn't always mean correct, but the burden of proof is on the 'gold bugs'.

> It would make much more sense to have a currency directly fixed to oil.

The price of oil goes up and down too much. People wouldn't want to loan or save a currency that changes value so much. The beauty with gold is the price would be stable, as to date no one's come up with a way of getting lots of it quickly and easily.

I know! Have a currency directly fixed to integers. Say, integers below X, where X is some reasonable granularity for the foreseeable future. There are exactly so many of them, and bank notes already have serial numbers, so it's technically possible! :>

People still keep searching for and mining gold. That was silly two thousand years ago, but they have the excuse that they didn't know better. I read that current methods used for mining gold in some countries (e.g. Argentina) are especially hazardous for public health and the environment of local populations.

You'd have to trust governments to not ever raise X. Because they will, and then you're in exactly the same situation as we're in now.

They can just as well 'unlink' from gold.

Why not cut to the chase and define the joule as standard unit of currency.

That would also work, in theory. It would also future proof the currency against developments that could make oil worthless, though I don't see that happening anytime soon.

At least right now, it makes a lot more sense to trade in an energy containing commodity than pure energy because it's easier and more familiar to people.

Joules are not equal. The sea is full of them. You have to look at entropy, too. A Joule of electricity would be a more practical measure.

Because it wouldn't be portable. Imagine paying for a restaurant dinner with 2 barrels of oil you had to haul over there.