Three Iron Laws of Social Science

From The Aphorisms of Merle Kling by Arnold Kling.  The subheading is His three iron laws of social science, and other sayings. 

Three Iron Laws of Social Science

He never wrote down what I consider his most important insight. Merle Kling’s Three Iron Laws of Social Science are:

Sometimes it’s this way, and sometimes it’s that way.

The data are insufficient.

The methodology is flawed

It was the ironic First Iron Law that he cited the most. Whenever a generalization in psychology or sociology or politics came up, and someone would bring up an exception, he would pipe up, “First Iron Law!”