 The issues here are clearly subtle and complex, and philosophers have only just begun to consider them. The central problem faced, as a philosopher, when trying to make sense of claims such as these is that there is no solid, unproblematic definition of background structure (and therefore background independence and dependence) on the table. Without this, one simply cannot decide who is right; one cannot decide which theories are background independent and which are not. Hence, an urgent issue in both physics and the philosophy of physics is to work out exactly what is meant by ‘background independence’ in a way that satisfies all parties, that is formally correct, and that satisfies our intuitive notions of the concept. Until this is achieved, background independence cannot be helpfully used to distinguish the approaches, nor can we profitably discuss its merits. A serious attempt to define background independence in such a way as to make these tasks possible has been made by Domenico Giulini (2007). But Giulini admits that a general definition still eludes us. The stumbling block might be that background independence simply isn’t a formal property of theories at all. Gordon Belot (2011b) has recently argued that background independence is partly an interpretive matter, and that one can have varying levels of background independence (the latter notion is also defended by Lee Smolin, 2006). Rickles (2008b) argues that the place to seek a notion of background independence that can be put to use in the quantum gravitational context is by focusing on the kinds of observables that an approach employs, rather than squarely on properties of the equations of motion.