The strongest evidence for Keynesianism, in my view, is introspection.  During the last five years, however, I’ve often heard Keynesians claim that their views have been vindicated by events.  To which I’m sorely tempted to respond:

It’s easy to claim “vindication by events” when your predictions are not only vague, but consistent with the main competing theories.

How could Keynesians convince me that events are really on their side?  The usual: Bets.  Find someone on “the other side” who disagrees with you, hammer out precise terms, and publicly shake on it.

I am not aware of any such Keynesian bets.  But I could easily have overlooked some.  Have I?  The closest thing to Keynesian bets of which I am aware, strangely, are the inflation bets that David Henderson and I made with Bob Murphy.  But I doubt that leading Keynesians want to accept EconLog bloggers as their intellectual representatives. 

Hopefully someone will point out some pertinent bets that I’ve overlooked.  In any case, though, the quantity of Keynesian wagering is not fixed.  My challenge for Keynesians: If you really believe in your own predictive acumen, could you please propose some bets?