I agree with what Anne Mayhew and Kevin Quin  wrote   
about Warsh's book.  Indeed the  book is not logically tight, but my   
point  is not  that  Warsh  has it  confused, but that the    
economists about whom he is writing had it confused.    
  
        Perhaps it has been empirically established that there are   
constant returns to scale, but, if so, that is very significant with   
respect to market  structure, as another respondent has pointed   
out.  
  
        There is, however,  much in another realm towards which    
Warsh's book points.  It is a history of economic thought, and, for   
all its illogic, it contains a very interesting story -- as Anne Mayhew   
has pointed out.  When it is put with Helpman's MYSTERY OF   
ECONOMIC GROWTH, it is an indication of the impossibility of   
pursuing theory apart from the history of  theory.  When  it is put    
with Lipsey's ECONOMIC TRANSFORMATIONS, it becomes   
evident that economic history is closely tied to economic theory.    
Because Lipsey and company are using theory to constrain   
understanding of the past, and using the past to establish, if not   
verify, theory.  
  
        Lipsey's account of 'All Purpose Inventions" entails   
Romer's "endogenous growth model", about which Warsh  has   
written.  (I hope I understand all of this correctly.)   
  
        I  conclude that neither Economic History nor the History   
or Economic Thought are about to pass away, though they may   
not be closely tied to  their institutionalization in academia.  
  
        But I have  been too dogmatic in  writing this, and I    
wonder  what you all think with respect to these matters.  Further,   
there is  much more that could be said  about "Romer and Warsh",   
 For example,  I have read Kurtz's (I hope  that  is the name)   
critique of Romer.  It recently appeared  on this server.  Clearly the    
limitations of  particular theories are of some concern.  Indeed the   
limitations of all theories in  Economics are of fundamental concern.  
Which is not  to say that because limited  theories are of no use   
whatsoever.  
  
And again further,  non-rivalrous goods, primarily information, and    
technological advance, which are at the heart  of Romer's theory   
have yet to be considered.  
  
Robin Neill