Abstract

Theodore Sider’s Four-Dimensionalism1 is a well-organized and clearly written book that is chock-full of important arguments. Both friends and foes of the views defended by Sider will benefit enormously from careful study of the book. I am going to focus on just two of Sider’s many arguments for Four-Dimensionalism: his argument from vagueness, which I take to be the most important and powerful argument in the book, and his argument from time travel, which I find to be the funnest to think about.