propositions 'he sits', 'he does not sit', so also the fact which
constitutes the matter of the proposition in one case is opposed
to that in the other, his sitting, that is to say, to his not
sitting.

It is evident that 'positives' and 'privatives' are not opposed
each to each in the same sense as relatives. The one is not
explained by reference to the other; sight is not sight of
blindness, nor is any other preposition used to indicate the
relation. Similarly blindness is not said to be blindness of
sight, but rather, privation of sight. Relatives, moreover,
reciprocate; if blindness, therefore, were a relative, there
would be a reciprocity of relation between it and that with which
it was correlative. But this is not the case. Sight is not called
the sight of blindness.

That those terms which fall under the heads of 'positives' and
'privatives' are not opposed each to each as contraries, either,
is plain from the following facts: Of a pair of contraries such
that they have no intermediate, one or the other must needs be
present in the subject in which they naturally subsist, or of
which they are 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