Steve, let me try to interpret this statement by Robbins in terms of   
error. My reading of the passage is that Robbins is claiming that if   
"the economist" studies some HOT, he will be in a better position to   
avoid error in the "purely analytical field." Second, he is claiming   
that past policies led to problems, which presumably means that the past   
policies were erroneous.  
   
I wonder how Robbins would judge whether an error has been made in the   
analytical field and how he would determine whether a problem exists   
that was caused by past policies. What kinds of problems does he   
mention? And what kinds of policies does he think led to these problems?  
  
It is all well and good to write that errors have occurred. But such   
writing is purely rhetorical until one specifies these errors in a way   
that a reader can judge whether the writer herself is making an error.  
  
Pat Gunning