Colander: What’s your view of the New Keynesian approach? Tobin: I’m not sure what that means. If it means people like Greg Mankiw, I don’t regard them as Keynesians. I don’t think they have involuntary unemployment or absence of market clearing. It is a misnomer to call Mankiw any form of Keynesian. Colander: How about real-business-cycle theorists? Tobin: Well, that’s just the enemy.
David Colander, "Conversations with James Tobin and Robert J. Shiller on the “Yale Tradition” in Macroeconomics", Macroeconomic Dynamics (1999), later published in Inside the economist’s mind: conversations with eminent economists (2007) edited by Paul A. Samuelson and William A. Barnett.