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