Keynes was halfway right about the facts
‘There is no harm in being sometimes wrong, especially if one is promptly found out’
John Maynard Keynes is often quoted as saying: “When the facts change, I change my mind. What do you do, sir?” Photograph: Picture Post/Getty Images
When I was much younger and editing an economics journal, I published an article by a distinguished professor – more distinguished, perhaps, for his policy pronouncements than his scholarship.
At a late stage, I grew suspicious of some of the numbers in one of his tables and, on making my own calculations, found they were wrong. I rang him. Without apology, he suggested I insert the correct data. Did he, I tentatively enquired, wish to review the text and its conclusions in light of these corrections, or at least to see the amended table? No, he responded briskly.
The incident shocked me then: but I am wiser now. I have read some of the literature on confirmation bias: the tendency we all have to interpret evidence as demonstrating the validity of our views. I have learned such bias is almost as common in academia as among the viewers of Fox News: John Ioannidis’s work has shown how few scientific studies can be replicated successfully. In my inexperience I had foolishly attempted such replication before the article was published.
Valiant struggleJohn Maynard KeynesPaul Samuelson
There is a subtle, but important, difference between “the facts” and “my information”. The former refers to some objective change that is, or should be, apparent to all: the latter to the speaker’s knowledge of relevant facts. It requires greater intellectual magnanimity to acknowledge that additional information might imply a different conclusion to the same problem than it does to acknowledge that different problems have different solutions. But Keynes might have done better to say: “Even when the facts don’t change, I (sometimes) change my mind.” The history of his evolving thought reveals that he evidently felt no shame in doing so. As he really did say: “There is no harm in being sometimes wrong – especially if one is promptly found out.”
Mark of intelligenceF Scott Fitzgerald
The capacity to act while recognising the limits of one’s knowledge is an essential, but rare, characteristic of the effective political or business leader. “Some people are more certain of everything than I am of anything,” wrote former US treasury secretary Robert Rubin. We can imagine which politicians he meant.
– Copyright The Financial Times Limited 2015