In “Does Special Relativity Have a Dynamical Explanation?” I argue, contra Harvey Brown, that the kinematical structure picked out by special relativity need not have an explanation, dynamical or otherwise, and that it plays an important role in explaining characteristic relativistic phenomena such as length contraction. I open by explaining the relationship between kinematics and dynamics generally in physics, and elucidate this by comparing special relativity as a kinematical framework to Galilean relativity and the Lorentz ether theory. Along the way I explore a famous thought experiment from the physicist J.S. Bell and show why its implications don’t provide the support for Brown’s view that he hoped.

“The Night Sky and the Blank Canvas: Disambiguating Background Independence” moves to a parallel set of issues in the more complex setting of general relativity. Einstein credited Mach with some of the inspiration for his most famous theory, but since the decline of logical positivism it has generally been agreed that general relativity does not comport with Mach’s strict demands on physical theory. I raise a qualified challenge to this consensus. While I agree that Mach’s and Einstein’s philosophical demands on physical theory are not all well-conceived, I believe this is not the whole story. I argue that consideration of Einstein’s description of space in Newtonian mechanics as “causally absolute” leads us to a picture of background independence that shows how general relativity satisfies many typically Machian worries about space—and that shows general relativity to be not a paragon of background independence, but rather an important step towards background independence.