t only one aeviternity.

_On the contrary,_ Aeviternity is a more simple thing than time, and is
nearer to eternity. But time is one only. Therefore much more is
aeviternity one only.

_I answer that,_ A twofold opinion exists on this subject. Some say
there is only one aeviternity; others that there are many
aeviternities. Which of these is true, may be considered from the
cause why time is one; for we can rise from corporeal things to the
knowledge of spiritual things.

Now some say that there is only one time for temporal things,
forasmuch as one number exists for all things numbered; as time is a
number, according to the Philosopher (Physic. iv). This, however,
is not a sufficient reason; because time is not a number abstracted
from the thing numbered, but existing in the thing numbered;
otherwise it would not be continuous; for ten ells of cloth are
continuous not by reason of the number, but by reason of the thing
numbered. Now number as it exists in the thing numbered, is not the
same for all; but it is different for different things. Hence, others
assert that the unity of eternity as the principle of all duration is
the cause of the unity of time. Thus all durations are one in that
view, in the light of their principle, but are many in the light of
the diversity of things receiving duration from the influx of the
first principle. On the other hand others assign primary matter as
the cause why time is one; as it is the first subject of movement,
the measure of which is time. Neither of these reasons, however, is
sufficient; forasmuch as things which are one in principle, or in
subject, especially if distant, are not one absolutely, but
accidentally. Therefore the true reason why time is one, is to be
found in the oneness of the first movement by which, since it is most
simple, all other movements are measured. Therefore time is referred
to that movement, not only as a measure is to the thing measured, but
also as accident is to subject; and thus receives unity from it.
Whereas to other movements it is compared only as the measure is to
the thing measured. Hence it is not multiplied by their multitude,
because by one separate measure many things can be measured.

This being established, we must observe that a twofold opinion existed
concerning spiritual substances. Some said that all proceeded from God
in a certain equality, as Origen said (Peri Archon. i); or at least
many of them, as some others thought. Ot