Found this through Cafe Hayek – Why Do Futurists Get So Much Wrong?

The Austrian economist Ludwig Lachmann once walked into the colloquium room at New York University, where the blackboard displayed this quotation: “When it comes to the future, one word says it all: You never know. – Y. Berra.”

Having built much of his economics on the unknowability of the future, Lachmann noticed the quote. However, having lived in South Africa for decades and being unfamiliar with the wit and wisdom of the former New York Yankees catcher, he pondered the chalk inscription for a bit, turned to those assembled, and in his heavy accent said, “I’m afraid I’m not familiar with the works of Professor Berra.”