Colleagues:

The other problem with Say's law is that many analysts who rely on it  
as a rationale for anti-keynesianism did not actually read J.B. Say. I  
mean the original writings in French; and this case, I am sorry to  
say, the English translations out there are not completely  
satisfactory. One needs to realize that:

1/ With respect to his so called "law", Say contradicted himself on  
numerous occasions.

2/ There are six different editions of Principes d'économie politique,  
with significant modifications of the text. For those who actually  
read them, the contradictions and exceptions to his so called law are  
evident. For instance, Say acknowledged that hoarding may constitute a  
serious impediment to his "law".
Read the édition variorium edited by Mouchot et al. (2006).

3/The passages pertaining to the "law" in the Cours d'économie  
politique are even more puzzling.

The so called Say's law is neither a pre-Neoclassical concept, nor a  
Classical idea. At the very best, it is a hybrid flawed concept. The  
fact of the matter is, there are many so called Say's "laws", and  
there are exceptions that invalidate the "laws" all stated by Say  
himself. One cannot overlook this very important point. This is why  
rational reconstructions should be combined with historical  
reconstructions in order to prevent some exaggerations and  
misinterpretations.

Guy NUMA, Ph.D.
Assistant Professor of Economics