een an infinite and a
negative proposition may depend upon a hyphen. It has been proposed,
indeed, with a view to superficial simplification, to turn all
Negatives into Infinites, and thus render all propositions Affirmative
in Quality. But although every proposition both affirms and denies
something according to the aspect in which you regard it (as _Snow is
white_ denies that it is any other colour, and _Snow is not blue_
affirms that it is some other colour), yet there is a great difference
between the definite affirmation of a genuine affirmative and the vague
affirmation of a negative or infinite; so that materially an affirmative
infinite is the same as a negative.

Generally Mill's remark is true, that affirmation and denial stand for
distinctions of fact that cannot be got rid of by manipulation of words.
Whether granite sinks in water, or not; whether the rook lives a hundred
years, or not; whether a man has a hundred dollars in his pocket, or
not; whether human bones have ever been found in Pliocene strata, or
not; such alternatives require distinct forms of expression. At the same
time, it may be granted that many facts admit of being stated with
nearly equal propriety in either Quality, as _No man is proof against
flattery_, or _All men are open to flattery_.

But whatever advantage there is in occasionally changing the Quality of
a proposition may be gained by the process of Obversion (chap. vii. Sec.
5); whilst to use only one Quality would impair the elasticity of
logical expression. It is a postulate of Logic that the negative sign
may be transferred from the copula to the predicate, or from the
predicate to the copula, without altering the sense of a proposition;
and this is justified by the experience that not to have an attribute
and to be without it are the same thing.

Sec. 3. A. I. E. O.--Combining the two kinds of Quantity, Universal and
Particular, with the two kinds of Quality, Affirmative and Negative, we
get four simple types of proposition, which it is usual to symbolise by
the letters A. I. E. O., thus:

A. Universal Affirmative -- All S is P.
I. Particular Affirmative -- Some S is P.
E. Universal Negative -- No S is P.
O. Particular Negative -- Some S is not P.

As an aid to the remembering of these symbols we may observe that A. and
I. are the first two vowels in _affirmo_ and that E. and O. are the
vowels in _nego_.

It must be acknowledged that these four kind