Grain rots within a few months, comes in vastly varying qualities and is generally pretty useless as a serious means of exchange. Value is a subjective estimate of a good -- one which can never reduced to any one single dimension of the good in question, such as its utility. The value of a particular piece of bread might very well be
sentimental, religious or something else entirely. Claiming that bread derives its value from its utility is a half-truth at best.
The problem with a fiat currency is that it is backed by absolutely nothing. The paper bills you carry in your pocket represent nothing except themselves, and are, qua means of exchange, valued on account of their relative scarcity alone. (Notice that I do not try to deny that the above made point applies to money as well. Any particular object can be valued for many reasons -- many coins have a value qua antiquities, for example -- but the most common reason why people want more money is that it is hard to come by, quite simply.). Gold is something more than a colorful piece of paper. Gold is a rare precious metal that you cannot simply print more of as you see fit. The supply of gold is determined by natural factors, and not by government decree.
You claim that fiat currencies are "backed by the national economy as a whole", but how on god's green earth do you propose that that backing works? How would that backing even be expressed? As has been stated the government does not guarantee you any particular slice of the "national economy" (as if that was the government's to give away in the first place) in exchange for any of its notes. The notes are, by the very definition of a fiat currency, not backed by *anything*. They are what they are, nothing more, nothing less. A colorful piece of paper with an entirely arbitrary number printed on them. They cannot be exchanged at a bank for *anything*. A gold standard note can always be exchanged for a very specific amount of gold.
Perhaps what you actually mean is that the government tries to maintain price stability? But how does it do that, then? By trying to make sure that certain more or less arbitrary collections of goods (
http://en.wikipedia.org/wiki/CPI) always remain at the same constant *numerical price* as expressed in fiat money! That's not stability!
Lets assume that I invent a method that allows me to sell bread at half its current price. The effect that this wonderful invention of mine would have on the national bank is to make it -- after the values have been crunched through the banks various more or less arbitrary indices -- print more money, to ensure that the price of bread remain "stable". This has -- among other things -- the extremely negative effect of masking and obfuscating price drops that occur through natural technological advances. Of course, this is highly illusory -- the price of bread has still dropped -- the only difference is that the government now has stolen a little bit of value from every holder of its currency, all with the expressed aim of guaranteeing that the *number* printed on the loaf of bread does not change! The effect that any sane consumer would *really* like to see is of course that the price of bread drops, quite simply, as that is the best expression of the underlying productive factors of the economy. This also befuddles completely the completely unimaginable amount of other factors involved in a price setting mechanism. Bread might not be as valued today as it was yesterday -- on account, for example, of salad becoming more fashionable -- so bread always having the same numerical price is a pointless goal in any event. The relationship of bread to the rest of the market is not the same from day to day.
Nothing in life is stable, and the object of a currency cannot be to remain static in relation to something else, as there is no constant in relation to which it could remain stable. What I want from a currency -- a value storage -- is that it should not lose value simply by me having it in my pocket. If anything I would like it to gain value. I would personally prefer it if I could have my value stored in a metal -- something that no one can magically create more of -- rather than in a note that the government openly and proudly boasts that it is printing more of. Do you see that that printing reduces the value of all my money? Do you see that the value that disappears from my money goes directly into the government's pockets, as they are the first to put the new "money" into circulation?
Fiat money loses value over time, as the government prints more of it. This runs completely contrary to one of the qualities that are always cited when talking about qualities sought from a currency, namely value preservation over time. Gold has historically proven itself as an extremely useful -- the most useful, in fact -- preserver of value, yet we do not use it as such. Why? Because the government wants to control your wallet, because inflation is an extremely efficient and stealthy means of taxation.
You claim that the government surely does not abuse this power, and apart from this being naive, it is also wrong. The government -- openly and admittedly so -- abuses that power to the tune of several percent each year. In Sweden, the 50-öring (half a krona) is now being removed from circulation, simply because the government over the last thirty years, since the collapse of the bretton woods system, has debased the currency so much that the coin is now essentially worthless compared to other coins in circulation. Before that the 50-öring had been in circulation for at least a couple of hundred years, why this sudden change in the weather? The
Maria Theresia Thaler -- in further contrast -- was used uninterruptedly for 250 years, simply because it was struck from pure silver, and thus not capable of losing value simply because some bureaucrat or other decided that it should. What coin would you rather have had in your pocket, a Maria Theresia Thaler or a Swedish 50-öring from 1985? (They were obviously never of comparable denominations, but I trust that you see my point here).
Honestly now, what would you prefer? A thousand dollars in cash, or a thousand dollars in gold doubloons? I think that the answer is pretty given. One of those must be spent immediately or lose 2-4-6-8-10% of its value every year, the other you can sit on for thousands of years and it'll still be worth a shitton.
So why don't I use gold? Because the government -- at gunpoint -- maintains a monopoly on the issuing of currency. If that was not the case -- if banking was a free market -- I don't think anyone would be using government money, and the government seems to agree with me on that estimate (Why else have the laws). There are no constitutional or parliamentary checks on the central bank. In fact, most western countries make an expressed point of having an "independent" central bank. Unchecked power is always abused. Furthermore government power should never be accepted by default, it must always be motivated. Do you really think that I should be forbidden from issuing a currency of my own? If so, why? Why must this be a government monopoly to begin with? If it wasn't, I would have very little quarrel with the government issuing monopoly currency, as no one would be stupid enough to use it.
In Haven metal -- among other things -- lacks several of the comparative qualities that it has IRL which would make it more meaningful as a value storage. Food, for example, decays in real life.
