ABSTRACT
This chapter focuses at the relevant doctrines of Galileo and Descartes, and then move on to Leibniz's attacks on substantivalism. It considers some impacts on the classical debate of the contemporary concept of 'spacetime'. In his Dialogue Concerning the Two Chief World Systems, Ptolemaic and Copernican, Galileo set out to prove that the Earth moves; specifically, that it rotates on its own axis once per day, and rotates around the Sun once per year. The influential piece of analysis played a vital role in the defence of Copernicanism. Newton is plainly committed to the undetectability of both the static and kinematic shifts whereas Leibniz was committed to the principle of the identity of indiscernibles (PII). Since Newton's arguments about absolute and relative space in the Scholium and elsewhere often take Descartes as their target, it will prove helpful to know something of what Descartes himself had to say about these matters.
