It may be that these mistakes were excusable on the basis of the knowledge available to men at the time – though I happen to think not. But that is really beside the point. Any system which gives so much power and so much discretion to a few men that mistakes – excusable or not – can have such far-reaching effects is a bad system. It is a bad system to believers in freedom just because it gives a few men such power without any effective check by the body politic – this is the key political argument against an "independent" central bank. But it is a bad system even to those who set security higher than freedom. Mistakes, excusable or not, cannot be avoided in a system which disperses responsibility yet gives a few men great power, and which thereby makes important policy actions highly dependent on accidents of personality. This is the key technical argument against an "independent" bank. To paraphrase Clemenceau, money is much too serious a matter to be left to the Central Bankers.
Milton Friedman, Capitalism and Freedom, via Peter Boettke .