and veteration be referred to the measure itself. For
since "before" and "after" of duration cannot exist together, if
aeviternity has "before" and "after," it must follow that with the
receding of the first part of aeviternity, the after part of
aeviternity must newly appear; and thus innovation would occur in
aeviternity itself, as it does in time. And if they be referred to
the things measured, even then an incongruity would follow. For a
thing which exists in time grows old with time, because it has a
changeable existence, and from the changeableness of a thing
measured, there follows "before" and "after" in the measure, as is
clear from _Physic._ iv. Therefore the fact that an aeviternal thing
is neither inveterate, nor subject to innovation, comes from its
changelessness; and consequently its measure does not contain
"before" and "after." We say then that since eternity is the measure
of a permanent being, in so far as anything recedes from permanence
of being, it recedes from eternity. Now some things recede from
permanence of being, so that their being is subject to change, or
consists in change; and these things are measured by time, as are all
movements, and also the being of all things corruptible. But others
recede less from permanence of being, forasmuch as their being
neither consists in change, nor is the subject of change;
nevertheless they have change annexed to them either actually or
potentially. This appears in the heavenly bodies, the substantial
being of which is unchangeable; and yet with unchangeable being they
have changeableness of place. The same applies to the angels, who
have an unchangeable being as regards their nature with
changeableness as regards choice; moreover they have changeableness
of intelligence, of affections and of places in their own degree.
Therefore these are measured by aeviternity which is a mean between
eternity and time. But the being that is measured by eternity is not
changeable, nor is it annexed to change. In this way time has
"before" and "after"; aeviternity in itself has no "before" and
"after," which can, however, be annexed to it; while eternity has
neither "before" nor "after," nor is it compatible with such at all.

Reply Obj. 1: Spiritual creatures as regards successive affections
and intelligences are measured by time. Hence also Augustine says
(Gen. ad lit. viii, 20, 22, 23) that to be moved through time, is
to be moved by affections. But as regards thei