OK Bob Murphy is clearly not getting it (here, and he thinks I'm "upset" here).
Bob regularly battles Don Boudreaux and William Anderson for the title of Krugmaniac-in-chief, but I'm more fond of Bob because he's a nice, smart guy and you can actually talk to him about this stuff, so I think he actually has a chance of getting how weird this post by Williamson is.
As a preface, I actually agree with Williamson on a lot of what he has to say (Michael Woodford has said this sort of thing in the past about macro too), much more than I agree with some of Krugman's melodrama. I agree with Williamson that economic science is good at selecting good ideas, and that there's a pretty good consensus among macroeconomists despite the perception that they never agree (this is actually referre to as the "new consensus model"). And what's more, it's got a lot of Keynesian features to it. And Williamson (despite being a junior Krugmaniac), is a great blogger.
But there was something fundamentally weird about the post that I thought everyone would get.
So Williamson starts off by blasting Krugman for not knowing modern macro. To a certain extent it's true - Krugman almost certainly does not keep up with the details these days - but he definitely knows the broad outlines of modern macro, and he knows a lot more of the details than the average person pontificating on it. So Williamson probably overstates the point a little, but that's basically fine.
What's amazing to me is that in launching into what constitutes modern macro, Williamson goes through a litany of ideas that are forty years old, and well integrated into Krugman's body of work.
Bob has to be able to see how weird and funny this is.
Williamson is up to the task of duking it out with Krugman - and I wish he did. That would be a good discussion to follow. But he didn't do it in this post.
"Freshwater" really isn't that big of a mystery here. It has always referred to the Treasury View, demand denialism, and strong Ricardian equivalence. It's definitely out there. It's even more common among policymakers than economists (thankfully), and many economists who when pressed do an about face do make statements like this. Nobody that follows Krugman as closely as Bob does should be confused about this point.
"Freshwater" is not a take-down of the Phelps volume or expectations in macro.