McTaggart begins his paper “The Unreality of Time”, by distinguishing the A-Series from the B-
Series, as ways of ordering positions in time. The ordering according to past, present and future
is the A-Series, the ordering according to earlier and later is the B-Series.
Time involves change. There can be no time without change (if nothing changed).
If time exists, then moments, or events, must be ordered either via the A-series or the B-series.
Can time be constituted solely by the B-series? That is, can change apply to reality if past,
present and future do not?
But what, on the B-series, changes? Events? The only way that events can change is to go from
being future, to being present, to being past. But that just is the A-series. In no other respects can
an event change. If event O is earlier that N and later than M, then it will always be so. So it
always exists in a B-series, so it cannot come to be and then cease to be. O just is an existent
event. McTaggart makes the point that events cannot change, and in this, he is correct. But is this
what change consists in? Events changing? What about persisting physical objects?
Therefore, “the B-series is not by itself sufficient to constitute time, since time involves change.”
One major objection to this.
Past, etc., only exist in relation to a knowing subject. Change consists in an object having
one property at time T and another, contrary property at T’ (i.e. when a sentence ascribing
a property to an object is true at T and not true at T.) Russell turns it into a discussion of
the truth of propositions. For him, change consists in a proposition about an object being
true at one time, and false at another. For example, ‘the poker is hot’ is true at T and false
at T’. To return to metaphysics, the poker has the property of hotness at T and does not