I have only a couple of things to add at this stage to what Peter   
Boettke wrote to John and to what I wrote before regarding his   
interpretation of Mises.  
  
In my judgment, it is not quite correct to say that Mises (or I) treats   
an imaginary construction as an "abstraction from reality." It is   
correct, as I see it,  to say that Mises regards the method of imaginary   
constructions as a means, and perhaps even the only means, for human   
beings to define and comprehend reality. To apply this method, one   
contrasts what our senses reveal with what we imagine our senses could   
reveal. This, in my view, is what Mises means in Human Action and   
elsewhere when he writes of the method of imaginary constructions. If   
you think that he means more (or less) than this, I think you are wrong.   
I disagree very much with your implication that this idea is trivial,   
especially insofar as it is used to define and comprehend economic reality.  
  
Your quote from Mises regarding the use of imaginary constructions that   
have no counterpart in reality must be read in context, as I see it. You   
should note that it is from a chapter in which Mises is concerned with   
economics and not, more generally, with all phenomena or even with   
praxeological phenomena. [In Misesian taxonomy, economic phenomena are   
one type of praxeological phenomena. And praxeological phenomena are one   
type of phenomena, a type that differs from non-praxeological   
phenomena.] The self-contradictory images he has in mind in this chapter   
are well accepted in economics. An example is the centrally planned,   
fully coordinated system that contains the same specialized behavior as   
a market economy. Another is an economic system that contains prices but   
no money holding. I suspect that few economists would doubt the   
usefulness of these images in economics. Whether they fit your idea of   
"abstractions from reality" or your idea of "self-contradictory images   
with no counterpart in reality" is uncertain.  
  
But perhaps you mean to challenge these views of most economists.  
  
Pat Gunning