The Complete Aristotle (eng.)

and only incidentally of coming into being, and
of being. A sufficient evidence of this is that nothing comes into
being without itself moving somehow and acting, but a thing can be
destroyed even if it does not move at all. And this is what, as a
rule, we chiefly mean by a thing’s being destroyed by time. Still,
time does not work even this change; even this sort of change takes
place incidentally in time.
    We have stated, then, that time exists and what it is, and in
how many senses we speak of the ‘now’, and what ‘at some time’,
‘lately’, ‘presently’ or ‘just’, ‘long ago’, and ‘suddenly’
mean.
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14
    These distinctions having been drawn, it is evident that every
change and everything that moves is in time; for the distinction of
faster and slower exists in reference to all change, since it is
found in every instance. In the phrase ‘moving faster’ I refer to
that which changes before another into the condition in question,
when it moves over the same interval and with a regular movement;
e.g. in the case of locomotion, if both things move along the
circumference of a circle, or both along a straight line; and
similarly in all other cases. But what is before is in time; for we
say ‘before’ and ‘after’ with reference to the distance from the
‘now’, and the ‘now’ is the boundary of the past and the future; so
that since ‘nows’ are in time, the before and the after will be in
time too; for in that in which the ‘now’ is, the distance from the
‘now’ will also be. But ‘before’ is used contrariwise with
reference to past and to future time; for in the past we call
‘before’ what is farther from the ‘now’, and ‘after’ what is
nearer, but in the future we call the nearer ‘before’ and the
farther ‘after’. So that since the ‘before’ is in time, and every
movement involves a ‘before’, evidently every change and every
movement is in time.
    It is also worth considering how time can be related to the
soul; and why time is thought to be in everything, both in earth
and in sea and in heaven. Is because it is an attribute, or state,
or movement (since it is the number of movement) and all these
things are movable (for they are all in place), and time and
movement are together, both in respect of potentiality and in
respect of actuality?
    Whether if soul did not exist time would exist or not, is a
question that may fairly be asked; for if there cannot be some one
to count there cannot be anything that can be counted, so that
evidently there cannot be number; for number is either what has
been, or what can be, counted. But if nothing but soul, or in soul
reason, is qualified to count, there would not be time unless there
were soul, but only that of which time is an attribute, i.e. if
movement can exist without soul, and the before and after are
attributes of movement, and time is these qua numerable.
    One might also raise the question what sort of movement time is
the number of. Must we not say ‘of any kind’? For things both come
into being in time and pass away, and grow, and are altered in
time, and are moved locally; thus it is of each movement qua
movement that time is the number. And so it is simply the number of
continuous movement, not of any particular kind of it.
    But other things as well may have been moved now, and there
would be a number of each of the two movements. Is there another
time, then, and will there be two equal times at once? Surely not.
For a time that is both equal and simultaneous is one and the same
time, and even those that are not simultaneous are one in kind; for
if there were dogs, and horses, and seven of each, it would be the
same number. So, too, movements that have simultaneous limits have
the same time, yet the one may in fact be fast and the other not,
and one may be locomotion and the other alteration; still the time
of the two changes is the same if their number also is equal and
simultaneous; and for this reason, while the movements are
different and separate, the time is everywhere the same, because
the number of equal and simultaneous movements is everywhere one
and the same.
    Now there is such a thing as locomotion, and in locomotion there
is included circular movement, and everything is measured by some
one thing homogeneous with it, units by a unit, horses by a horse,
and similarly times by some definite time, and, as we said, time is
measured by