The assurance of a certain minimum income for everyone, or a sort of floor below which nobody need fall even when he is unable to provide for himself… - Friedrich Hayek

[Milton Friedman] believes in an oversimplified quantitative relationship between a measurable quantity of money and the price level. You must leave it to the discretion of the central bank to so adjust the supply of ultimate cash reserves as to keep the price level stable.

The newfangled word monetarism means of course no more than the good old “quantity theory of money”, as it was formulated in modern times by the late Professor Irving Fisher and reformulated by Professor Milton Friedman. Of this I said nearly 50 years ago in the first lecture I delivered in this country that “from a practical point of view, it would be one of the worst things which could befall us if the general public should ever again cease to believe in the elementary propositions of the quantity theory”. This was, however, unfortunately brought about by the seductive theories of Lord Keynes. I then said that it was in many respects a crude over-simplification, but the irrefutable chief content is still that inflation is always and everywhere the effect of an excessive supply of money and that it can be cured only by a restriction of its supply.

I don't know what monetarism is. If monetarism just means a good old-fashioned quantity theory, of course it has not failed. If it means the particular version of Milton Friedman, I think it has because he imagines that he can achieve — ascertain — a clear quantity relationship between a measurable quantity of money and the price level. I don't think that is possible. In fact, just about 40 years ago in the opening sentences of my book, Prices and Production, I wrote that it would be a great misfortune if people ever cease to believe in the quantity theory of money. It would be even worse ever to believe it literally. And that's exactly what Milton Friedman does.