 Our best physical theories have often had implications for the nature of time, and by and large, it is assumed that philosophers working on time need to be sensitive to the claims of contemporary physics. One example of the interaction between physics and philosophy of time that was mentioned in  Section 2  was Newton’s bucket argument, which used the observed effects of acceleration to argue for absolute motion (and thus absolute space and time). Another example mentioned above was the worry that the A-theory conflicted with special relativity. The latter has proved especially influential in contemporary metaphysics of time and so deserves some further discussion.