Is the development of an original/novel method a contribution to knowledge worthy of a PhD? 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".
While developing a method has merit within science, that method needs to be useful to answer a question which is not currently answerable. I too have worked primarily on methods development in graduate school, and got stung by this in some of my early work. So, while it's good to focus on the method, always have the question in front of you: "what do we want to know, that we can't know yet, that my method will be able to tell us?"