As a student, Ive seen a LOT of things in science... but I've actually "studied" probably nothing much beyond newtons laws ( I hope

I also presume that to successfully complete a doctorate, you need to know a helluva a lot about something, and not just bits and pieces here and there. So, I obviously presume a university, while looking at admit sheets, would probably feel a having "not-very-well-defined interests" is not exactly a good thing....
I know people who tend to pass this syndrome off as "interdisciplinary" work... which is what I'm going for too, but does it really work???