The humanities are not part of science. They aren't just a particularly soft science, they aren't a science period.
This post on /r/AskHistorians:
History isn’t science and it’s not a science. I find this issue prevalent among people who think that all knowledge is scientific and knowledge that isn’t scientific isn’t knowledge. Philosophically this is untenable, since the scientific method is not itself provable by the scientific method and is a form of presupposition. Methodologically this is untenable since history is not a discipline subject to experimentation. You cannot run repeatable experiments with the data of historical investigation.
And elsewhere: