I do not agree with Hugh Cameron that Say's Law is a "fallacy" of economics but then again
he doesn't list the statements so it is difficult to pass judgement as to whether or not
we have a genuine fallacy or just a statement that needs minor qualifications.  Please
remember that a rise in the minimum wage does help some workers---those who keep their
jobs!  The same can be said of rent control---a leading libertarian who I knew quite well
enjoyed a huge NYC apartment (6 rooms) most of his life do to the benefits of rent
control.
Without such amenities some of the most important writings of that last century   
might never have been written.  
  
 Still, in keeping with the spirit of his project I recommend what Ludwig von   
Mises called the "lump of labor fallacy" be added to the list.   At this time   
of intense debate about immigration reform, this fallacy keeps popping up.    
The claim is made that in any region (say, Alphaville) there is only so much   
work that needs to be done.  When the immigrants come into to Alphaville they   
leave less work for the natives to do and that means the immigrants cause   
unemployment.  Based on frequency with which many of hear this idea (I have   
economics majors in my class sharing this wisdom), I think it might indeed be not only a
major fallacy but also one of the most pernicious doctrines in the social sciences.
  
Another and perhaps more interesting question is to link the proposed   
fallacies to those economists who battled them in their lifetimes.  I mentioned von Mises
and of course there were many others.  I forgot who described economics as a "defensive
science," one that disarms those who might make our lives more tragic by ignorance or
hubris.
  
Laurence S. Moss