Building on xitel's comment, and in response to all the people saying that time must exist by referencing systems that evolve in time (cuddly_tomato, Baby_Tea), I'd like to point out something very irritating.
Time really doesn't have to exist. There are formulations of every equation in physics that are constructed without a time parameter, and they work. They work by considering relative positions of bodys as being the fundamental metric.
That's not to say that time, understood to be the parameter of intervals over which events occur, doesn't exist, merely that it doesn't have to exist for the universe to work they way it appears to us (including appearing to have time).
EDIT: As an aside, we've now constructed experiments that suggest information propagated backwards in time, if it does exist, so it's not much different than any other dimension if it is a real, physical thing.
Time really doesn't have to exist. There are formulations of every equation in physics that are constructed without a time parameter, and they work. They work by considering relative positions of bodys as being the fundamental metric.
That's not to say that time, understood to be the parameter of intervals over which events occur, doesn't exist, merely that it doesn't have to exist for the universe to work they way it appears to us (including appearing to have time).
EDIT: As an aside, we've now constructed experiments that suggest information propagated backwards in time, if it does exist, so it's not much different than any other dimension if it is a real, physical thing.