In other words attempting to apply scientific methods to social issues is fraught with dangers because the systems are not deterministic but chaotic.
An example presumably is Economics.
This of course overlooks that the main story of science in the last 100 years has been precisely to do with chaotic and probablistic systems such as quantum mechanics and Chaos theory (non-linear dynamics).
The development of these sort of tools is well suited for attempting to model policical and social or economic science but with how much sucess so far is questionable.
Many people have tried to use chaos theory to predict stock market movements for example but I don't know how sucessful they've been, I suspect not very