Overview of argument:

P1: Time is impossible without change.

P2: If there were a B-series but no A-series, there would be no change.

C1: Thus, time requires that there be an A-series.

P3: The reality of the A-series leads to a contradiction.

C2: Therefore, time does not exist.

Defense of P2:

Assume there is a B-series, i.e. that events are related by relations of earlier than and later than, but events don’t instantiate the property of being past, present, or future.

Anything we can say of this series, without invoking relations of being past, present, or future, is something that holds permanently. If event E is an event, it is always an event; if it occurs before event F, it is always true that it occurs before event F; etc.

Hence, if there is a B-series without an A-series, there would be no change.

Defense of P3:

No event can be past and present, or present and future, or ...

But every event has all of these characteristics!

Objection: E is present, was future, and will be past.

Reply: This means: E is present at a present moment of time, is future at a past moment of time, and is past at some future moment of time. But if E is present at a present moment of time t, this means it is not past at any past moment of time. However, it is past at all future times. But, as was originally pointed out, future times are equally present and past times, so if it is past at all future times, it is also past at all past moments of time, which we just said cannot be.