Why isn't time a vector? Hi, I found the following question in Halliday and Resnick's Physics Part I chapter on Vectors and the Laws of Motion. 5.We can order events in time. For example, event b may precede event c but follow event a, giving us a time order of events a, b, c. Hence there is a sense of time, distinguishing past, present and future. Is time a vector therefore? If not, why not? I'm stumped. Can you help me? Thanks.