The Complete Aristotle (eng.)

the second place, if there is to be change of change and
becoming of becoming, we shall have an infinite regress. Thus if
one of a series of changes is to be a change of change, the
preceding change must also be so: e.g. if simple becoming was ever
in process of becoming, then that which was becoming simple
becoming was also in process of becoming, so that we should not yet
have arrived at what was in process of simple becoming but only at
what was already in process of becoming in process of becoming. And
this again was sometime in process of becoming, so that even then
we should not have arrived at what was in process of simple
becoming. And since in an infinite series there is no first term,
here there will be no first stage and therefore no following stage
either. On this hypothesis, then, nothing can become or be moved or
change.
    Thirdly, if a thing is capable of any particular motion, it is
also capable of the corresponding contrary motion or the
corresponding coming to rest, and a thing that is capable of
becoming is also capable of perishing: consequently, if there be
becoming of becoming, that which is in process of becoming is in
process of perishing at the very moment when it has reached the
stage of becoming: since it cannot be in process of perishing when
it is just beginning to become or after it has ceased to become:
for that which is in process of perishing must be in existence.
    Fourthly, there must be a substrate underlying all processes of
becoming and changing. What can this be in the present case? It is
either the body or the soul that undergoes alteration: what is it
that correspondingly becomes motion or becoming? And again what is
the goal of their motion? It must be the motion or becoming of
something from something to something else. But in what sense can
this be so? For the becoming of learning cannot be learning: so
neither can the becoming of becoming be becoming, nor can the
becoming of any process be that process.
    Finally, since there are three kinds of motion, the substratum
and the goal of motion must be one or other of these, e.g.
locomotion will have to be altered or to be locally moved.
    To sum up, then, since everything that is moved is moved in one
of three ways, either accidentally, or partially, or essentially,
change can change only accidentally, as e.g. when a man who is
being restored to health runs or learns: and accidental change we
have long ago decided to leave out of account.
    Since, then, motion can belong neither to Being nor to Relation
nor to Agent and Patient, it remains that there can be motion only
in respect of Quality, Quantity, and Place: for with each of these
we have a pair of contraries. Motion in respect of Quality let us
call alteration, a general designation that is used to include both
contraries: and by Quality I do not here mean a property of
substance (in that sense that which constitutes a specific
distinction is a quality) but a passive quality in virtue of which
a thing is said to be acted on or to be incapable of being acted
on. Motion in respect of Quantity has no name that includes both
contraries, but it is called increase or decrease according as one
or the other is designated: that is to say motion in the direction
of complete magnitude is increase, motion in the contrary direction
is decrease. Motion in respect of Place has no name either general
or particular: but we may designate it by the general name of
locomotion, though strictly the term ‘locomotion’ is applicable to
things that change their place only when they have not the power to
come to a stand, and to things that do not move themselves
locally.
    Change within the same kind from a lesser to a greater or from a
greater to a lesser degree is alteration: for it is motion either
from a contrary or to a contrary, whether in an unqualified or in a
qualified sense: for change to a lesser degree of a quality will be
called change to the contrary of that quality, and change to a
greater degree of a quality will be regarded as change from the
contrary of that quality to the quality itself. It makes no
difference whether the change be qualified or unqualified, except
that in the former case the contraries will have to be contrary to
one another only in a qualified sense: and a thing’s possessing a
quality in a greater or in a lesser degree means the presence or
absence in it of more or less of the opposite quality. It is now
clear, then, that there are only these three kinds of