Philip Booth posts here about a recent TV performance by Ms Mazzucato. On the BBC, she claimed that "There is no evidence - no empirical evidence - that cutting capital gains tax or cutting corporate income tax will increase business investment". Surprise: Philip actually presents some empirical evidence that points in the opposite direction.
The statement Mazzucato made was definitive and very precise. But, in positive economics, nearly everything is arguable except for the fact that nearly everything is arguable. Mazzucato left the impression that her claim was simply not disputable, still less that there is a huge amount of evidence that points in the other direction.
I would think Ms Mazzucato is in complete good faith. We all have selection biases, after all.
I disagree deeply with Ms Mazzucato's "The Entrepreneurial State": but, if it has a remarkable feature, it is the fact that she openly describes hers as a "discursive battle." She doesn't like the narrative of government inefficiency, and she opposes it with a narrative of government efficiency. Her examples and alleged empirical proofs are to be placed in this context: which, in a way, she herself acknowledged.
To be fair with Ms Mazzucato, I believe that television debates are not really comparable to academic discussions. They are an unlikely venue to weigh opposite evidence and try to come up with something which may resemble the truth. Opinion makers go to TV, and they are more likely to be called back on TV, precisely because they can be assertive and give people answers, rather than helping them in asking the right questions. How many politicians or TV personalities have you ever listen uttering the words "I don't know"?
Philip is emphasizing a very serious problem. When it comes to social scientists on news stage, the public is induced to believe that somebody is an authority because of her research. But, on news programs, you are more likely to share your worldview, than your research findings. Philip suggests that "we should also have the humility (and courage) to admit when we think that the empirical evidence runs against our prior views or, at least, admit to the enormous areas of economics where the evidence cannot settle debates definitively." But though admirable, I'll bet such an attitude is going to be very rare. It just sounds so much better to claim we are appealing to "empirical evidence", than to our "moral intuitions", doesn't it?
For some people, coming to grasp with Philip's suggestion may be even harder. Particularly champions of the left (but that applies to some free marketers too) tend to believe that those who disagree with them do so because of some hidden motives. Holding the hypothesis that those who entertain very different ideas than ours are basically sell outs almost automatically reinforce our belief that the facts are on our side: others do not have a legitimate case, only interests they do not disclose. Unfortunately it seems to me there is no trend in contemporary politics that point in the direction of a more serene, and civilised, debate.