Last Friday, Scott Sumner posted a diatribe against the IS-LM triggered by aset of slides by Chris Foote of Harvard and the Boston Fed explaining how the effects of monetary policy can be analyzed using the IS-LM framework. What really annoys Scott is the following slide in which Foote compares the “spending (aka Keynesian) hypothesis” and the “money (aka Monetarist) hypothesis” as explanations for the Great Depression. I am also annoyed; whether more annoyed or less annoyed than Scott I can’t say, interpersonal comparisons of annoyance, like interpersonal comparisons of utility, being beyond the ken of economists. But our reasons for annoyance are a little different, so let me try to explore those reasons. But first, let’s look briefly at the source of our common annoyance.