Garett Jones on Open Borders: More Endogenous Than Thou

Garett Jones faults me for treating cross-country productivity differences as exogenous. I disagree. On further reflection, though, I think he’s making an analogous error. Ponder his statement:

As you know, my key disagreement is a theoretical and empirical one: the policy of Open Borders flows fairly naturally from the view that a nation’s level of productivity—total factor productivity or TFP to be pedantic—is largely exogenous to the experiences, backgrounds, and skills of a nation’s...