Home | Texts by category | | Quick Search:   
Works by Aristotle
Pages of Metaphysics

Previous | Next


be possible, then if A is real, B also must be real. For to say that B
must be possible, if A is possible, means this, that if A is real both
at the time when and in the way in which it was supposed capable of
being real, B also must then and in that way be real.

As all potencies are either innate, like the senses, or come by
practice, like the power of playing the flute, or by learning, like
artistic power, those which come by practice or by rational formula we
must acquire by previous exercise but this is not necessary with those
which are not of this nature and which imply passivity.
Since that which is 'capable' is capable of something and at
some time in some way (with all the other qualifications which must be
present in the definition), and since some things can produce change
according to a rational formula and their potencies involve such a
formula, while other things are nonrational and their potencies are
non-rational, and the former potencies must be in a living thing,
while the latter can be both in the living and in the lifeless; as
regards potencies of the latter kind, when the agent and the patient
meet in the way appropriate to the potency in question, the one must
act and the other be acted on, but with the former kind of potency
this is not necessary. For the nonrational potencies are all
productive of one effect each, but the rational produce contrary
effects, so that if they produced their effects necessarily they would
produce contrary effects at the same time; but this is impossible.
There must, then, be something else that decides; I mean by this,
desire or will. For whichever of two things the animal desires
decisively, it will do, when it is present, and meets the passive
object, in the way appropriate to the potency in question. Therefore
everything which has a rational potency, when it desires that for
which it has a potency and in the circumstances in which it has the
potency, must do this. And it has the potency in question when the
passive object is present and is in a certain state; if not it will
not be able to act. (To add the qualification 'if nothing external
prevents it' is not further necessary; for it has the potency on the
terms on which this is a potency of acting, and it is this not in
all circumstances but on certain conditions, among which will be the
exclusion of external hindrances; for these are barred by some of
the positive qualifications.) And so even if one has a rational
wish, or an appetite, to do two things or contrary things at the
same time, one will not do them; for it is not on these terms that one
has the potency for them, nor is it a potency of doing both at the
same time, since one will do the things which it is a potency of
doing, on the terms on which one has the potency.

Since we have treated of the kind of potency which is related to
movement, let us discuss actuality-what, and what kind of thing,
actuality is. For in the course of our analysis it will also become
clear, with regard to the potential, that we not only ascribe
potency to that whose nature it is to move something else, or to be
moved by something else, either without qualification or in some
particular way, but also use the word in another sense, which is the
reason of the inquiry in the course of which we have discussed these
previous senses also. Actuality, then, is the existence of a thing not
in the way which we express by 'potentially'; we say that potentially,
for instance, a statue of Hermes is in the block of wood and the
half-line is in the whole, because it might be separated out, and we
call even the man who is not studying a man of science, if he is
capable of studying; the thing that stands in contrast to each of
these exists actually. Our meaning can be seen in the particular cases
by induction, and we must not seek a definition of everything but be
content to grasp the analogy, that it is as that which is building
is to that which is capable of building, and the waking to the

Previous | Next
Site Search