Translational Invariance and Newton's God

Tim Maudlin is writing a two-volume introduction to the philosophy of physics, and I was fortunate enough to get a peek at a draft of Volume One, about space and time. There is one anecdote in there about Leibniz's objections to Newtonian physics that is worth passing along. This came up in the course of the Leibniz-Clarke correspondence. Leibniz was quite fond of proclaiming overarching a priori principles. Perhaps the most famous/infamous is the Principle of Sufficient Reason, which states that everything that happens does so for some good reason. But there was also the Principle of Identity of Indiscernibles, which states that if two things have all the same properties, they are really the same thing. Sounds reasonable enough (although one might worry what qualifies as a "property"), but it can get you in trouble if you take it too far. Remember that Newton believed in absolute space -- ...