There is a *ton* of things people on here could say on the intentions and practice of 'interdisciplinarity', its close cousins like multi-disciplinarity, trans-disciplinarity and so on, but for the moment, let us not get into semantic debates (and what they may indicate).
1. We all have our feet in some discipline/s or the other, this does not mean we are bounded by them. yes, departmental funding, faculty recruitment does go by these things, but for your own intellectual practice you are free perhaps to interface with as many fields as you may care for (as long as it makes sense)
2. Social sciences overlap and cut onto on another and it is often at the boundaries of fields that the most exciting research happens, if you can bring opposing bodies of theory in conversation, that's great, but that is something which is done all the time by interesting researchers who sit in the department of X Y or Z, and travel across boundaries. Sometimes, it is easier said than done, but you'll find out.
3. You will also find out soon that being 'interdisciplinary' is not as easy as it sounds, disciplines are often locked in fierce paradigmatic clashes, so forth, some seek convergence, others oppose convergence, multiple issues abound and such issues range from allocation of funds to the sociology of citation circles: you will discover that in your own time.
4. Finally, I work with a scholar whose home discipline and faculty apointment was and is in Subject X and who is the leading voice in the field of Y, in the interim having synthesized insights and collaborated within fields of A B G T R and D. You get my drift. Your appointment, or the office in which you sit being in a particular dept does influence certain things, but not everything.
5. On other issues, the problems (epistemological, methodological, mundane-financial), politics and fallouts of 'interdisciplinarity'....there are fantastic PhD-ers on here working on interdisciplinary issues, and they will doubtless come up with great insights.
All best, and goodnight!
