Why is "literature, history and philosophy" referred to as the traditional humanities?

The liberal arts are usually categorized into humanities (not "humanities", mind you) and social sciences, and this is already known in the academic community***. In terms of subject content, the liberal arts are further divided into "history" or "theory". Humanities, social sciences division of the "history" or "learning" research, not too meaningful, because different "learning" is generally incommensurable, unless the general history. But for "theory" or "theoretical" research, it is extremely important to emphasize the division between humanities and social sciences. Humanities theory belongs to the field of value theory, which includes humanities philosophy, humanities aesthetics and so on, they are allowed or even rely on the subject of perception and experience to participate in the difficult or no need for empirical testing, can be self-explanatory, so different humanities theories can not be generalized; the social sciences belong to the scope of the sciences, in addition to the usual sociology, economics, psychology, anthropology, jurisprudence, and also includes the nature of the social sciences of the philosophical, Aesthetics, they have an ontology methodology epistemology practice unity characteristics, need to be able to reveal the objective truth, can withstand the empirical test