This letter to the editor to the NYTimes helped me understand why we don't:
Re “Yes, Economics Is a Science” (Op-Ed, Oct. 21): ...
It is good to hear that economics is entering a phase when rigorous analysis and empirical testing will become the norm. . . . Scholars of physics, chemistry and medicine can study the movement of atomic particles or lab mice without any concern that the particles and the mice are interested in the results. . . .
DAVID C. WROBEL
New York, Oct. 21, 2013
The writer is a lawyer.