Take the social science I studied, linguistics. How does it lack falsifiability? Theories of how languages evolved can be disproven by contradictory evidence in the same way theories would be in any scientific discipline. For example, we know English and German ultimately have a common ancestor, because we can see the similarities between their modern and older forms and explain them in terms of consistent sound changes, and we can systematically explain the differences between the older forms of the two languages such that we can reconstruct what we think is their precursor, and then show in the same fashion that they are related to other European languages. Now, if you believe English and German are in fact descended from ancient Chinese, you can falsify the current theory by showing how they could have evolved, but you can't, because any similarities are superficial and can't be explained systematically.
Or did you mean only social sciences that you don't like? Which ones?