The Complete Aristotle (eng.)

be the
other.
    But what is moved is moved from something to something, and all
magnitude is continuous. Therefore the movement goes with the
magnitude. Because the magnitude is continuous, the movement too
must be continuous, and if the movement, then the time; for the
time that has passed is always thought to be in proportion to the
movement.
    The distinction of ‘before’ and ‘after’ holds primarily, then,
in place; and there in virtue of relative position. Since then
‘before’ and ‘after’ hold in magnitude, they must hold also in
movement, these corresponding to those. But also in time the
distinction of ‘before’ and ‘after’ must hold, for time and
movement always correspond with each other. The ‘before’ and
‘after’ in motion is identical in substratum with motion yet
differs from it in definition, and is not identical with
motion.
    But we apprehend time only when we have marked motion, marking
it by ‘before’ and ‘after’; and it is only when we have perceived
‘before’ and ‘after’ in motion that we say that time has elapsed.
Now we mark them by judging that A and B are different, and that
some third thing is intermediate to them. When we think of the
extremes as different from the middle and the mind pronounces that
the ‘nows’ are two, one before and one after, it is then that we
say that there is time, and this that we say is time. For what is
bounded by the ‘now’ is thought to be time-we may assume this.
    When, therefore, we perceive the ‘now’ one, and neither as
before and after in a motion nor as an identity but in relation to
a ‘before’ and an ‘after’, no time is thought to have elapsed,
because there has been no motion either. On the other hand, when we
do perceive a ‘before’ and an ‘after’, then we say that there is
time. For time is just this-number of motion in respect of ‘before’
and ‘after’.
    Hence time is not movement, but only movement in so far as it
admits of enumeration. A proof of this: we discriminate the more or
the less by number, but more or less movement by time. Time then is
a kind of number. (Number, we must note, is used in two senses-both
of what is counted or the countable and also of that with which we
count. Time obviously is what is counted, not that with which we
count: there are different kinds of thing.) Just as motion is a
perpetual succession, so also is time. But every simultaneous time
is self-identical; for the ‘now’ as a subject is an identity, but
it accepts different attributes. The ‘now’ measures time, in so far
as time involves the ‘before and after’.
    The ‘now’ in one sense is the same, in another it is not the
same. In so far as it is in succession, it is different (which is
just what its being was supposed to mean), but its substratum is an
identity: for motion, as was said, goes with magnitude, and time,
as we maintain, with motion. Similarly, then, there corresponds to
the point the body which is carried along, and by which we are
aware of the motion and of the ‘before and after’ involved in it.
This is an identical substratum (whether a point or a stone or
something else of the kind), but it has different attributes as the
sophists assume that Coriscus’ being in the Lyceum is a different
thing from Coriscus’ being in the market-place. And the body which
is carried along is different, in so far as it is at one time here
and at another there. But the ‘now’ corresponds to the body that is
carried along, as time corresponds to the motion. For it is by
means of the body that is carried along that we become aware of the
‘before and after’ the motion, and if we regard these as countable
we get the ‘now’. Hence in these also the ‘now’ as substratum
remains the same (for it is what is before and after in movement),
but what is predicated of it is different; for it is in so far as
the ‘before and after’ is numerable that we get the ‘now’. This is
what is most knowable: for, similarly, motion is known because of
that which is moved, locomotion because of that which is carried.
what is carried is a real thing, the movement is not. Thus what is
called ‘now’ in one sense is always the same; in another it is not
the same: for this is true also of what is carried.
    Clearly, too, if there were no time, there would be no ‘now’,
and vice versa. just as the moving body and its locomotion involve
each other mutually, so too do the number of the moving