<i>&gt; movement relative to other objects is fundamental</i><p>I agree that &quot;objective space&quot; in the sense of &quot;a space that is the same for everyone&quot;, is not required to give an account of movement of objects relative to other objects. However, the only reason we know that is that we have an alternative: a theory of objective <i>spacetime</i> that gives an account of movement of objects relative to other objects.<p>In other words, according to our best current classical theory, general relativity, Newton&#x27;s argument was flawed not because nothing objective is needed to account for the bucket experiment, but because he got wrong what thing was objective: he thought it was space, but it&#x27;s actually spacetime. More precisely, it&#x27;s the geometry of spacetime.<p>On the GR viewpoint, we can indeed view the rotation of Earth, for example, as relative in this sense: we can adopt a &quot;cosmic&quot; frame in which the Earth is spinning and the rest of the universe is at rest; or we can adopt a &quot;geocentric&quot; frame in which the Earth is at rest and the rest of the universe is spinning. Both frames are valid; neither one is &quot;preferred&quot; by the laws of physics. But both frames are describing the same underlying objective thing: the same geometry of spacetime. They are just describing it from different viewpoints.