Art History and the Philosophy of Social Sciences 1.: What is history?

What kind of knowledge is art history?  Is it a science, a branch of the humanities, or some combination? What is its relationship to the social sciences and the physical sciences?  These questions are interesting and important in themselves.  But they also shed light on contemporary debates in the philosophy of the social sciences.  For the art historian must constantly draw on the resources of sociology, anthropology, economics and so on, all themselves based on history to varying degrees.  So if we look at art history from the viewpoint of epistemology, we will naturally have to address the key issues in the philosophy of the social sciences: differences between and among the physical sciences, the social sciences, and the humanities; contrasts between causes and reasons; questions of reductionism and holism; issues of description, explanation and prediction; debates surrounding the nature of objectivity, interpretation, and understanding (verstehen), and so forth.  And of course, the absolutely central issue of historicism is particularly important here because art history is, after all, an historical discipline.  To study the epistemology of art history is to engage all of these issues.