The social sciences are useless. So why do we study them? Here’s a good reason: — Andrew Gelman

While what Andrew Gelman says is correct, I would approach this issue somewhat differently.

Owing to the nature of subject matter of the natural, ergodicity is involved, albeit more in physics and chemistry than biology, where complex adaptive systems and emergence are a strong factor. The social science have to deal with learning from feedback and consequent adjustment to changing conditions.

A good example is the conventional approach to economics, which is highly formalized and modeled on natural science, assuming that the subject matter of economics is subject to similar type of invariance as the natural sciences when it is not. The meagre results of conventional economics testifies to that.

This is indicated by business schools having abandoned the method of conventional economic for the case method, after its efficacy having been shown by Harvard Business School. Social science tends to follow this model, using targeted studies rather than general theory, for the simple reason that a framework for generating theories in the social sciences does not (yet) exist.

Some social scientist have attempted to model their approach on conventional economics, specifically Gary Becker's rational choice theory, but without convincing success. The reason is two-fold.

First, humans are not homogenous. Even though humans have essentially the same hardware and more or less the same software operating system, called "nature," they are different on many other ways that are acquired (nurture).

Even if humans were the same in most respects, which data questions, rational pursuit of individual objectives doesn't lead to optimization (let alone maximization) owing to the fallacy of composition. Individual behavior cannot be assumed to optimize social behavior. Thrift is a virtue individually, but if everyone saves, the group is adversely affected by demand leakage, resulting in under-consumption of economic capacity.

As Andrew Gelman notes, the social sciences are not totally useless, only less useful since they don't produce technology like the natural and life sciences do. But it is better than flying blind. Social scientists just need to be more modest about the ability of social sciences to resolve human issues. 

Statistical Modeling, Causal Inference, and Social Science

The social sciences are useless. So why do we study them? Here’s a good reason:
Andrew Gelman | Professor of Statistics and Political Science and Director of the Applied Statistics Center, Columbia University