As far as Friedman's arguments are concerned, I always thought that he sang two tunes. In the economic profession, he was absolutely reasonable. I could find no distinction between his modern quantity theory of money and eclectic Keynesian economics. But in writing for , he argued a hard monetarism, as against the soft monetarism of the "modern quantity theory." In hard monetarism, velocity is constant and but the money supply matters for nominal GNP. I thought that was just factually wrong.
Milton Friedman