A PhD is supposed to be an "original contribution to knowledge". In my own PhD (in an area of Earth Science) I have so far focused on developing a particular method of computer modeling that will hopefully have a range of applications in my field. In short, my question is: Is the development of an original/novel method a contribution to knowledge worthy of a PhD?
The reason for asking this is that my supervisor seems concerned that I am drifting away from the 'pure science questions' in my field - i.e I ought to be trying to address a fundamental research question with this new model, rather than spending most of my time developing and testing a new method.
My instinct says that it should be just as valid, and browsing some of the other PhD theses from the department suggests that a few others have gone down this route. I also see plenty of papers published that are more 'methods-focused' than 'fundamental-question-addressing'. Personally, I get a lot more satisfaction from pursuing the former kind of research, even though I accept I am not directly answering 'the big questions' as my supervisor puts it.
On the other hand, I don't predict an entirely healthy academic relationship down the line if our opinion on what constitutes an interesting PhD thesis differs so fundamentally, and I also consider the possibility that I could just be plain wrong in my interpretation of "original contribution to knowledge".