This conflates social science with the humanities. I agree with respect to the humanities. Less so with respect to social science. People in large groups do in general follow certain trends and we do have decent ways of establishing causation. Now there is a lot of stuff that people do that we can't analyze quantitatively due to lack of data or other blockers. For these qualitative methods will have to do. Fine, but…
When you describe continental drift, it doesn’t make the plates go faster. When you do economics, it changes the economy. Social sciences have a worse reflexivity problem than the arts, because with art, nothing turns on whether it’s right or wrong. With social sciences, if your hypothesis is wrong but widely believed, you can still kick off seventy years of communism.
Eg, a free market puts tremendous downwards pressure on profit margins. Identifying that means the powers that be fight against free markets with hook and crook - but it doesn't change the fact that if there is a free market it will find an equilibrium where people are indifferent to starting a new business.