re
in this sense the true and necessary are eternal, because they are in
the eternal mind, which is the divine intellect alone; hence it does
not follow that anything beside God is eternal.
______________________

FOURTH ARTICLE [I. Q. 10, Art. 4]

Whether Eternity Differs from Time?

Objection 1: It seems that eternity does not differ from time. For two
measures of duration cannot exist together, unless one is part of the
other; for instance two days or two hours cannot be together;
nevertheless, we may say that a day or an hour are together,
considering hour as part of a day. But eternity and time occur
together, each of which imports a certain measure of duration. Since
therefore eternity is not a part of time, forasmuch as eternity
exceeds time, and includes it, it seems that time is a part of
eternity, and is not a different thing from eternity.

Obj. 2: Further, according to the Philosopher (Phys. iv), the "now"
of time remains the same in the whole of time. But the nature of
eternity seems to be that it is the same indivisible thing in the
whole space of time. Therefore eternity is the "now" of time. But the
"now" of time is not substantially different from time. Therefore
eternity is not substantially different from time.

Obj. 3: Further, as the measure of the first movement is the
measure of every movement, as said in Phys. iv, it thus appears that
the measure of the first being is that of every being. But eternity is
the measure of the first being--that is, of the divine being.
Therefore eternity is the measure of every being. But the being of
things corruptible is measured by time. Time therefore is either
eternity or is a part of eternity.

_On the contrary,_ Eternity is simultaneously whole. But time has a
"before" and an "after." Therefore time and eternity are not the same
thing.

_I answer that,_ It is manifest that time and eternity are not the same.
Some have founded this difference on the fact that eternity has
neither beginning nor an end; whereas time has a beginning and an end.
This, however, makes a merely accidental, and not an absolute
difference because, granted that time always was and always will be,
according to the idea of those who think the movement of the heavens
goes on for ever, there would yet remain a difference between eternity
and time, as Boethius says (De Consol. v), arising from the fact that
eternity is simultaneously whole; which cannot be applied to time: for
eter