  Thus according to McTaggart the source of time and change must be found in the \(A\)-series. But the \(A\)-series implies a vicious regress. Any event must have all three properties, pastness, presentness and futurity, but this is a contradiction. The only way out of the contradiction is to say that the event is past, present and future at different times; but the same question arises about the temporal instants themselves, which would force us to appeal to a further time series to avoid the contradiction.