 Focussing on the qualified geometrical approach, there are also questions regarding the particular sense in which spacetime structure can be said to be explanatory of dynamical symmetries. One notion of explanation discussed in this literature is that of a ‘constructive explanation’.This is derivative on Einstein’s distinction between ‘principle theories’ and ‘constructive theories’ (Einstein 1919): for detailed discussion, see (Brown 2005, §5.2). In brief, a constructive explanation is one in which phenomenological effects are explained by reference to real (but possibly unobservable) physical bodies. (For further discussion of how to understand constructive theories and explanations, see (Frisch 2011).) With the idea of a constructive explanation in mind, one can say this: if a proponent of a geometrical view hypostatizes spacetime, then they can give constructive explanations of certain physical effects by appeal to that spacetime structure; otherwise, they cannot. That said, even if one does not hypostatise spacetime, and so concedes that spacetime cannot offer constructive explanations of the behaviour of matter, it is not obvious that spacetime cannot still facilitate other kinds of explanation. For discussions of these issues, see (Acuña 2016; Dorato &amp; Felline 2010; Frisch 2011; Read 2020b).