While I can't say with certainty whether mild and predictable deflation is bad for the economy, I don't think that these standard arguments that are used are sufficiently persuasive.<p>1) It is clear that a deflationary spiral, defined as possessing the characteristics of being unexpected, not written into contracts or loans, and relatively severe (double digits) while accelerating is bad. The great depression makes this clear. We can also see it in the current Greek situation. However, runaway inflation is equally bad, as we can see from post WW1 Germany, and modern day Venezuela and Argentina. Is it the fact that the change in the buying power of money is large and unexpected, or is it the sign of the inflation percentage that is bad?<p>2) Under the current debt based money system, the negative effects of inflation fall primarily on the poor. The wealthy purchase government bonds, which protect them inflation. They also have bank accounts, or finance debt either directly or indirectly. This means that instead of inflation falling on the populace evenly, it falls doubly on the poor.<p>3) Under a constant money supply system that eschews debt, the rich must seek out investment that actually increases productivity, rather than doing parasitic zero-sum investments (such as bond purchases and loan giving) that merely transfer value from one person to another. This would tend to grow the economy faster.<p>4) Under a constant money supply (like Bitcoin in a few years), wages and prices would tend fall by however much the economy was growing (2% - 3% a year), but the raises that people give out for seniority would tend to overwhelm the wage issues.