I generally agree with Paul Krugman, so it is exiting that I am outraged by something he wrote (I've calmed down now).
Paul Krugman says that scratchpads are useful. They are sloppy easy models which are not taken seriously. Or maybe which shouldn't be taken seriously, but it's not a big problem that many powerful people take them literally. I lose my temper.
Short version: If an economist alone in the woods keeps the limitations of a scratchpad in mind while a tree falls does it make policy sound ?
For the actual post click this link.
"Madmen in authority, who hear voices in the air, are distilling their frenzy from some academic scribbler of a few years back", but they can't be trusted to remember the necessary conditions for the academic's theorems.