definite;
it is not necessarily always the same opposite, but against
whatever opposite it is, they are always homogeneous. One colour is
contradistinguished from another colour, one shade from another shade:
colour may be contradistinguished from shape, but it is within the
common genus of sensible qualities.

A curious confirmation of this law of our thinking has been pointed
out by Mr. Carl Abel.[3] In Egyptian hieroglyphics, the oldest
extant language, we find, he says, a large number of symbols with
two meanings, the one the exact opposite of the other. Thus the
same symbol represents _strong_ and _weak_; _above_--_below_;
_with_--_without_; _for_--_against_. This is what the Hegelians mean
by the reconciliation of antagonisms in higher unities. They do not
mean that black is white, but only that black and white have something
in common--they are both colours.

I have said that this law of Homogeneous Counter-relativity has not
been recognised by logicians. This, however, is only to say that it
has not been explicitly formulated and named, as not being required
for Syllogism; a law so all-pervading could not escape recognition,
tacit or express. And accordingly we find that it is practically
assumed in Definition: it is really the basis of definition _per
genus et differentiam_. When we wish to have a definite conception
of anything, to apprehend what it is, we place it in some genus and
distinguish it from species of the same. In fact our law might be
called the Law of Specification: in obeying the logical law of what
we ought to do with a view to clear thinking, we are only doing with
exactness and conscious method what we all do and cannot help doing
with more or less definiteness in our ordinary thinking.

It is thus seen that logicians conform to this law when they are
not occupied with the narrow considerations proper to Syllogism. And
another unconscious recognition of it may be found in most logical
text-books. Theoretically the not-A of the Law of Contradiction--(A is
not not-A)--is an infinite term. It stands for everything but A. This
is all that needs to be assumed for Conversion and Syllogism. But take
the examples given of the Formal Obverse or Permutation, "All men are
fallible". Most authorities would give as the Formal Obverse of this,
"No men are infallible". But, strictly speaking, "infallible" is
of more limited and definite signification than not-fallible.
Not-fallible, other than fallible,