An introductory text-book of logic - Mellone, Sydney - Rare Books at ...

342 THE PROBLEMS WHICH WE HAVE RAISED.
Thus, our result is that "S is not P" denies the
suggested affirmation
"
S is and is asserted on the
P,"
which excludes P.
positive basis that S is something
It is indeed obvious, from common language, that no
one ever thinks it worth while to deny things except
with reference to some actual or possible affirmation.
If I say to a man, "You cannot jump over the moon,"
he might think me mad ; but if I say,
" You
cannot
jump as high as that? he might either accept the
challenge or reply, "Well, I never said I could."
We now turn to a related question. Does every
affirmation involve the idea of a negation ? Whenever
we affirm anything we affirm a significant idea, a
meaning, or concept, in the logical sense. How is
the concept formed? By comparison, as we have seen.
Now comparison is impossible without distinction. This
is a very obvious fact ; I cannot compare things to
gether, or thoughts together, except by keeping them
distinct in my mind; if I have them distinct, then
I can note their resemblances. And distinction in
volves separation, exclusion, and, in other words, nega
tion. An affirmation, as
"
S is involves the P," general
idea of negation, but not the negation of that particular
connection of S and P. It involves the general idea
of negation, because we can only think of S and P
by distinguishing them respectively from things which
are not S and not P, and we can only think of the
relation
relations.
"
"
S is P
by distinguishing
This has been excellently stated by Professor
it from different
Minto. "Nothing is known absolutely or in isolation;
the various items of our knowledge are inter-relative;
everything is known by distinction from other things.
Light is known as the opposite of darkness, poverty
of riches, freedom of slavery, in of out ; each shade of