Does Hayek say that in any reference or letter?  How about an   
interview?  I would like to get the reference.  
  
Barkley's claim is what Anthony Waterman also made and now also   
Bruce has made this claim.  I am inclined to believe them, but I   
would just like to see the evidence.  
  
Obviously Hayek was deeply familiar with Mill, but on this issue   
Hayek is particuarly critical of Mill (see his critique of Mill for   
rational constructivism in The Constitution of Liberty).  So I am   
confused.  
  
We know he draws the inspiration for his work on this from   
Menger, and then from Mises (see his Trend of Economic Thinking   
paper) in which the distinction between planned and unplanned   
orders is viewed as critical.  
  
When Hayek was the editor of Economica, Polanyi was invited to   
write an essay on the 'growth of knowledge" in society in which I   
believe the term spontaneous order is utilized, and the discussion   
of "spontaneous order" is definitely in Polanyi's The Logic of   
Liberty.   When is the first time Hayek actually uses the term   
spontaneous order in his writing?  He certainly was talking about   
unplanned orders well before he talked about spontaneous order.  
  
I would be appreciative of learning the references.  
  
Peter Boettke