The Complete Aristotle (eng.)

predicated; for it is those, as we proved,’ in the case of
which this necessity obtains, that have no intermediate. Moreover,
we cited health and disease, odd and even, as instances. But those
contraries which have an intermediate are not subject to any such
necessity. It is not necessary that every substance, receptive of
such qualities, should be either black or white, cold or hot, for
something intermediate between these contraries may very well be
present in the subject. We proved, moreover, that those contraries
have an intermediate in the case of which the said necessity does
not obtain. Yet when one of the two contraries is a constitutive
property of the subject, as it is a constitutive property of fire
to be hot, of snow to be white, it is necessary determinately that
one of the two contraries, not one or the other, should be present
in the subject; for fire cannot be cold, or snow black. Thus, it is
not the case here that one of the two must needs be present in
every subject receptive of these qualities, but only in that
subject of which the one forms a constitutive property. Moreover,
in such cases it is one member of the pair determinately, and not
either the one or the other, which must be present.
    In the case of ‘positives’ and ‘privatives’, on the other hand,
neither of the aforesaid statements holds good. For it is not
necessary that a subject receptive of the qualities should always
have either the one or the other; that which has not yet advanced
to the state when sight is natural is not said either to be blind
or to see. Thus ‘positives’ and ‘privatives’ do not belong to that
class of contraries which consists of those which have no
intermediate. On the other hand, they do not belong either to that
class which consists of contraries which have an intermediate. For
under certain conditions it is necessary that either the one or the
other should form part of the constitution of every appropriate
subject. For when a thing has reached the stage when it is by
nature capable of sight, it will be said either to see or to be
blind, and that in an indeterminate sense, signifying that the
capacity may be either present or absent; for it is not necessary
either that it should see or that it should be blind, but that it
should be either in the one state or in the other. Yet in the case
of those contraries which have an intermediate we found that it was
never necessary that either the one or the other should be present
in every appropriate subject, but only that in certain subjects one
of the pair should be present, and that in a determinate sense. It
is, therefore, plain that ‘positives’ and ‘privatives’ are not
opposed each to each in either of the senses in which contraries
are opposed.
    Again, in the case of contraries, it is possible that there
should be changes from either into the other, while the subject
retains its identity, unless indeed one of the contraries is a
constitutive property of that subject, as heat is of fire. For it
is possible that that that which is healthy should become diseased,
that which is white, black, that which is cold, hot, that which is
good, bad, that which is bad, good. The bad man, if he is being
brought into a better way of life and thought, may make some
advance, however slight, and if he should once improve, even ever
so little, it is plain that he might change completely, or at any
rate make very great progress; for a man becomes more and more
easily moved to virtue, however small the improvement was at first.
It is, therefore, natural to suppose that he will make yet greater
progress than he has made in the past; and as this process goes on,
it will change him completely and establish him in the contrary
state, provided he is not hindered by lack of time. In the case of
‘positives’ and ‘privatives’, however, change in both directions is
impossible. There may be a change from possession to privation, but
not from privation to possession. The man who has become blind does
not regain his sight; the man who has become bald does not regain
his hair; the man who has lost his teeth does not grow his grow a
new set. (iv) Statements opposed as affirmation and negation belong
manifestly to a class which is distinct, for in this case, and in
this case only, it is necessary for the one opposite to be true and
the other false.
    Neither in the case of contraries, nor in the case of
correlatives, nor in the case of ‘positives’ and