Economists and empirical evidence

I don't suppose that economists are less likely than any of the rest of us to make  daft pronouncements about empirical issues without appearing to bother about the empirical evidence. So the letter to yesterday's FT  signed by a gang of 20 "leading economists" arguing (I use the word loosely) that the 50 pence top tax rate should be abolished isn't a particularly surprising event. The replies in today's FT from Alan Manning and Andrew Oswald (also leading economists) seem to me so reasonable - let's look at the existing evidence and wait for the new evidence that will shortly be available - that clearly there is some flaw in their reasoning that is so subtle that I haven't spotted it.

One member of the gang of 20 is the Cambridge economist Bob Rowthorn. This is the man who said in a 2008 interview with Alan Macfarlane:  "...I wouldn't regard myself as left-wing any more. I regard myself as left-wing in the sense that, saying there are a lot of poor people in the world that deserve a better deal and that those that are better off maybe could make some sacrifice." What kind of sacrifice would that be then? Obviously not one of a financial nature. In the course of the interview he confirms the essential soundness of his judgments by  confessing that he  supported the 1968 Soviet invasion of Czechoslovakia.

All arguments have to be considered on their merits, but perhaps Professor Rowthorn and his colleagues should take some advice from Oliver Cromwell: "I beseech you, in the bowels of Christ, think it possible you may be mistaken."