Re Rod Hay's remarks: Obviously, a human choosing between death and death is a dead human.
To suggest that capitalism is indistinguishable from slavery or from life in a
concentration camp may have some propagandistic value, but it is not a serious critique of
capitalism.  In fact, there are very few arguments in favor of the status quo as disarming
as the one that implies that its victims are absolutely powerless.
  
The classical political economists (and their radical German critic) made a very sharp
distinction between societies where extra-economic coercion prevailed and those where
economic coercion ruled.  And they all attributed the remarkable productive dynamism of
capitalist societies to the change in the *form* in which labor is coerced out of the
laborers.  Labor enters capitalist production as "free labor."  (I use quotes, but Marx
didn't.)  "Formal" does not mean fictitious or unimportant.
  
Peter G. Stillman suggests that there's a semantic/ideological slippery slope from
"constrained choice" to "choice" to "free choice" and Dr. Pangloss' world.  But if
constrains and freedom are opposites in a continuum, then choice is always both -- free
and constrained (it's like saying that loses are profits but negative, or vice versa).
But the real debate is not about the existence of a finite opportunity set: it is about
its size in each concrete case.
  
Michael Perelman asks, "[W]hy would the study of economics ignore the constraints and the
production of constraints?"  Again, I don't understand this
question: What economist in particular ignores the constraints and the (re)production of
the constraints, and where?  If we claim that all or most conventional economists do this
(moreover, that serious conventional economists do this), then we really undermine the
critique of conventional economics.
  
Nicholas J. Theocarakis asks, "Why not have a theory of constraints instead? [not a
duality theorem].  Once the parameters of the game are set, choices -- and their analysis
-- might be trivial."  What?  Rule human agency out of history?  A theory of social life
governed by iron laws of history over and above history?
  
"By the way, the number of stupid ideologues should not be underestimated.   
Soon, they will be cited more often than the rest."  I sympathize with Nicholas' concern,
but we won't win by fighting a caricature.  That's a decoy.
  
Julio Huato