 Sklar proposes interpreting ‘true’ acceleration as a primitive quantity not defined in terms of motion relative to anything, be it absolute space, a connection or other bodies. (Ray 1991 points out the family resemblance between this proposal and Leibniz’s suggestion that vis viva addresses Newton’s Scholium arguments.) Van Fraassen proposes formulating mechanics as ‘Newton’s Laws hold in some frame’, so that the form of the laws and the contingent relative motions of bodies – not absolute space or a connection, or even any instantaneous relations – pick out a standard of true motion, namely with respect to such an ‘inertial frame’. These proposals aim to keep the full explanatory resources of Newtonian mechanics, and hence admit ‘true acceleration’, but deny any relations between bodies and spacetime itself. Like the actual Leibniz, they allow absolute quantities of motion, but claim that space and time themselves are nothing but the relations between bodies.