There are two major counterpoints here. The first, which has already been mentioned, is that economists do agree on many things. The second big point is that t

There are two major counterpoints here. The first, which has already been mentioned, is that economists do agree on many things. The second big point is that the profession actually does (mostly) agree on monetary policy when interest rates are comfortably positive. In the mainstream, it's widely agreed that when interest rates are positive, a) the fed controls inflation and b) the Taylor rule is a good approximation of what the fed should do. When interest rates hit 0 in 2008-9, the field was thrown in disarray. Roughly, neo-Keynesians like Krugman believe the fed no longer controls inflation (or controls it less well) and so fiscal stimulus is necessary to supplement monetary policy. Neo-monetarists like Sumner believe the Fed continues to control inflation, via QE, so the Fed should just continue to use the Taylor rule but use QE instead of interest rates and basically just pump out money as long as the Taylor rule calls for negative rates, echoing Milton Friedman's advice for Japan in the 90's (which Krugman agreed with at the time!!).* According to both those views, monetary or fiscal stimulus have been inadequate. Due to the unprecedented nature of QE an opposing camp has strengthened, arguing that the fed's actions have been reckless and ineffectual. These have been joined by dissenting voices, such as the Austrian real business cycle theorists which have always been opposed to fed intervention in the money supply. The recent crisis raised new problems that the field has yet to grapple with. But finding good answers is likely to be very important. As events proceed, it will hopefully become obvious which concerns and predictions are warranted. I see the process as a healthy scientific debate, not a reason to throw out the whole field. * To be more technical, they actually call for an abandonment of the Taylor rule and its replacement with NGDP level targeting, but in effect those are actually quite similar. One important motivation is to move away from equating interest rates with monetary policy, since interest rates aren't useful at the ZLB.